u/LogicGU

JTWC Warning #6 Analysis – Tropical Storm Saudel
converted to miles and mph for easier reading.

This is a meaningful and generally favorable track update for the populated southern Marianas, while the intensity forecast has become more concerning. Saudel has accelerated sharply and is now firmly moving northwest, and JTWC has upgraded its near-term track confidence to high.

Summary
Saudel is about 216 miles north-northeast of Chuuk.
It moved northwest at about 16 mph during the past 6 hours.
Significant wave height increased to about 18 feet.
Saudel has accelerated substantially: roughly 11 mph NNW → 16 mph NW.
The northwest track is forecast to continue for the next 3 days.
The subtropical ridge northeast of Saudel has taken control of steering.
After Day 3, the ridge should move west and turn Saudel more west-northwest.
Rapid intensification is now forecast to begin in only 12–36 hours.
JTWC forecasts a peak around 145 mph in approximately 3 days.
Track confidence has increased from medium → high through Day 3.
Model spread has tightened.
Forecast Change Score: 7/10
Warning #6 is more important than #5 because two things have become substantially clearer:
Track confidence improved.
Rapid intensification moved closer.
The track is becoming less concerning for Guam/Rota/Tinian/Saipan, while the northern CNMI threat and intensity potential are becoming more serious.

What Changed From Warning #5?
1. Saudel accelerated significantly
Warning #5:
NNW at ~11 mph
Warning #6:
NW at ~16 mph
That’s a significant increase.
Saudel is no longer slowly wandering around in a weak steering environment. The subtropical ridge northeast of the cyclone is now taking control.
That’s important because one of our biggest questions over the past few updates was:
Will Saudel gain enough latitude before eventually turning WNW?
It increasingly looks like the answer is yes.

2. Track confidence increased
This is one of the biggest positive developments.
Warning #5 had medium confidence.
Warning #6:
HIGH confidence through Day 3.
The cross-track spread at Day 3 has tightened to:
148 km / about 92 miles
That’s down from approximately 115 miles previously.
The models are increasingly agreeing on where Saudel is going.

3. Rapid intensification starts sooner
Warning #5 had RI beginning after approximately 36 hours.
Warning #6 now says:
RI in 12–36 hours.
That’s a significant change.
The expected explosive strengthening period has moved considerably closer.

Track and Steering
The steering pattern is now considerably simpler.
The subtropical ridge northeast of Saudel is building and taking control.
Because Saudel sits along the southwestern side of that ridge, the clockwise flow around the ridge is steering the cyclone:
Northwest
And JTWC expects that NW motion to continue for approximately 3 days.
That’s important.
Every additional hour Saudel spends moving northwest rather than west allows it to gain more latitude before reaching the longitude of the Marianas.
After Day 3
The subtropical ridge itself migrates westward.
As the ridge extends farther north of Saudel, the steering flow flattens.
That’s when the track changes:
NW → WNW
But by then Saudel should already be considerably farther north.
This is becoming a much more favorable steering configuration for Guam and the southern CNMI than the early Warning #1–3 scenarios.

Intensity – This Is Becoming the Main Story
Saudel is still disorganized.
That’s essentially the only thing preventing much faster strengthening right now.
JTWC expects approximately:
Next 12 hours
Around 50 mph
Then, once the circulation becomes organized and symmetrical:
Rapid intensification begins.
The environment ahead is extremely favorable:
Very warm ocean
High ocean heat content
Low wind shear
Improving organization
Favorable upper-level outflow
JTWC now forecasts Saudel reaching:
Approximately 145 mph in around 3 days.
That’s Category 4-equivalent intensity.
And importantly, this puts the strongest portion of the intensification relatively close to the Northern Marianas passage.

Possible Eyewall Replacement Cycle
We also have our first meaningful mention of a potential eyewall replacement cycle.
HAFS-A suggests one could occur around Day 3.
If that happens, Saudel could temporarily:
Stop intensifying
Weaken somewhat
Develop a larger eye
Expand its wind field
Then it could potentially reorganize afterward.
The timing is still far too uncertain to know whether that would help or hurt any particular island.

Model Guidance
Track guidance continues to improve.
Day 3 cross-track spread
148 km / 92 miles
Day 5 cross-track spread
125 nautical miles / about 144 miles
That’s a considerable improvement from Warning #5, when Day-5 spread was approximately 380 miles.
There is still uncertainty regarding timing.
NAVGEM and JGSM move Saudel about 144 miles farther along the track than most other guidance by Day 3.
But that’s primarily an along-track/speed disagreement, not a major disagreement about the direction.
JTWC therefore assigns:
Days 0–3: HIGH track confidence
After Day 3: MEDIUM confidence
That’s probably the strongest track-confidence signal we’ve had for Saudel so far.

Island Risk Assessment
My interpretation of Warning #6, not official probabilities.

Guam
Direct eyewall risk: Very Low
Estimated direct-hit chance: <1–2%
Overall impact risk: Low
Trend: Lower
Saudel is accelerating northwest and gaining latitude. The increasingly tight model consensus strongly favors a track well north of Guam.

Rota
Direct eyewall risk: Very Low
Estimated direct-hit chance: 1–3%
Overall impact risk: Low
Trend: Lower
Rota continues moving farther away from the favored corridor as Saudel gains latitude.

Tinian
Direct eyewall risk: Very Low to Low
Estimated direct-hit chance: 2–4%
Overall impact risk: Low to Moderate
Trend: Lower
The combination of continued NW motion and improving model agreement is favorable for Tinian.

Saipan
Direct eyewall risk: Low
Estimated direct-hit chance: 4–8%
Overall impact risk: Moderate
Trend: Lower
Saipan remains the closest major populated island, but the track trend continues to improve. Saudel is gaining latitude rapidly and the model envelope is tightening.
Peripheral effects and dangerous seas could still occur depending on Saudel’s eventual size.

Pagan
Direct eyewall risk: Moderate to High
Overall impact risk: High to Very High
Trend: Remains primary concern
Pagan remains much closer to the expected corridor. With Saudel potentially approaching Category 4-equivalent intensity, even a near miss could produce severe conditions.

Alamagan / Agrihan
Direct eyewall risk: Moderate to High
Overall impact risk: High to Very High
These northern islands remain much more exposed to the current forecast track than Saipan and the southern islands.

What I’m Watching for in Warning #7
We now have less reason to obsess over every tiny track wobble because the steering environment is becoming established and JTWC has high track confidence.
Instead, I’d watch three things.

First: Does Saudel maintain the NW heading?
If it continues NW at around 15–16 mph, confidence should increase further that the southern Marianas stay safely south of the core.

Second: Does RI actually begin?
JTWC moved the RI window forward to 12–36 hours.
If satellite imagery suddenly shows a symmetrical core developing, we could see Saudel’s intensity climb very quickly.

Third: How large does Saudel become?
Even with the center well north of Saipan, a large Category 4 typhoon can produce dangerous seas, surf and peripheral winds well away from the eye.

Bottom Line
Warning #6 is good news for Guam, Rota, Tinian and increasingly Saipan from a track perspective.
Saudel has accelerated to approximately 16 mph toward the northwest, the subtropical ridge has taken control of steering, model spread has tightened, and JTWC now has high confidence in the track through the next 3 days.
The concern is shifting decisively toward the northern Marianas and Saudel’s intensity.
Rapid intensification could begin within 12–36 hours, with JTWC forecasting approximately 145 mph by Day 3.
So compared with Warning #5:
Southern Marianas track risk: down.
Northern Marians risk: remains high.
Rapid-intensification concern: up significantly.

The typhoon threat for Guam is almost non existent so this will be my last update. Have a blessed day and wonderful weekend. Stay safe everyone.

Converted to mph and miles for easier reading

This is a fairly important update because Saudel has now started moving north, which is exactly the type of poleward movement JTWC had been waiting for. The overall forecast continues to favor a passage well north of Saipan, while the intensity forecast remains potentially serious.

Summary
Saudel is about 166 miles east-northeast of Chuuk.
It moved north at about 4 mph over the past 6 hours.
Significant wave height has increased to about 15 feet.
Forward speed should increase during the next 12 hours as the steering pattern becomes better established.
Closest approach to Saipan remains around 161 miles.
After about 3 days, Saudel should bend more west-northwest as the subtropical ridge builds north of it.
JTWC forecasts approximately 80 mph in 2 days, followed by rapid intensification.
Official peak forecast: about 145 mph in 4 days.
Individual intensity guidance ranges considerably higher, with the strongest model around 168 mph.
Track models are in good agreement through Day 3 with no significant outliers.

Forecast Change Score: 6/10
The biggest development isn’t a major change in the forecast track. It’s that the actual storm motion is finally behaving more like the forecast expected.
Previously we had that unusual WSW movement while the circulation was poorly organized.
Now:
WSW → North
That’s significant because gaining latitude before the future westward/WNW turn is exactly what keeps Saudel farther away from Guam, Rota, Tinian and Saipan.

What Changed From the Previous Update?
The previous update had Saudel moving west-southwest at roughly 4 mph.
JTWC thought that was probably temporary, caused by:
Weak steering
A developing circulation
Strongest winds wrapping around the southeastern side
Possible relocation of the developing low-level center
Now Saudel is moving:
North at approximately 4 mph.
That supports JTWC’s previous forecast that the storm would begin gaining latitude.
The forecast closest approach to Saipan also remains around 161 miles, so there hasn’t been a meaningful southward correction toward the populated southern Marianas.
That’s encouraging.

Track and Steering
The steering setup is becoming easier to understand.
Right now
The subtropical ridge south of Japan is weakening and retreating northward.
That opens a pathway for Saudel to move north and gain latitude.
At the same time, another subtropical ridge northeast of Saudel is building southwestward.
Eventually, that second ridge becomes the dominant steering mechanism.
What happens next?
For roughly the next 2–3 days:
Saudel gains latitude and generally moves NNW/NW.
Then the ridge extends farther west north of Saudel.
Once that happens, it begins preventing the storm from continuing north.
The track bends more:
West-northwest
So the sequence we’re looking for is approximately:
North now → NNW/NW → WNW after Day 3
The critical part for the Marianas is how much latitude Saudel gains before that WNW turn occurs.
So far, the northward movement is favorable for the populated southern islands.

Intensity
This remains the part of the forecast that concerns me most.
Saudel is still asymmetric and dealing with some dry air.
But conditions should improve rapidly.
During the next 12–48 hours:
Dry-air intrusion decreases
The core becomes wetter
The wind field becomes more symmetrical
Outflow improves
JTWC currently forecasts Saudel reaching approximately:
80 mph in 2 days.
Then the environment becomes extremely favorable.
Saudel should encounter:
Sea temperatures above 86°F
High ocean heat content
Strong upper-level outflow
Dual-channel outflow
That last one is particularly favorable for strong intensification because the cyclone has efficient pathways for evacuating air from the top of the storm.
JTWC then forecasts rapid intensification to approximately:
145 mph by Day 4
That’s Category 4-equivalent intensity.

There’s an Interesting Intensity Disagreement
This is worth watching.
Some rapid-intensification guidance thinks Saudel could strengthen much faster than JTWC currently forecasts.
At Day 2:
JTWC: about 80 mph
RI guidance: around 110 mph
That’s roughly a 30 mph difference.
JTWC is deliberately choosing the weaker solution because Saudel’s circulation is still asymmetric.
Essentially, they’re saying:
The environment could support explosive strengthening, but the storm isn’t organized enough yet to take full advantage of it.
If Saudel becomes symmetrical faster than expected, JTWC specifically acknowledges that more rapid intensification could occur earlier.
That’s something I’d watch very closely in the next update.

Model Guidance
Track guidance has improved.
JTWC says there are currently no notable track outliers through Day 3.
Cross-track spread at Day 3 is approximately:
185 km / 115 miles
After Day 3, uncertainty increases.
NAVGEM becomes the northern outlier toward Iwo To.
Removing NAVGEM, the Day-5 spread is approximately:
389 km / 242 miles
So confidence is considerably better around the Marianas passage than farther downstream.

Island Risk Assessment
My interpretation of this JTWC forecast, not official probabilities.
Guam
Direct eyewall risk: Very Low
Estimated direct-hit chance: 1–3%
Overall impact risk: Low
Trend: Lower
The northward movement is good news for Guam. Saudel is gaining latitude before its eventual WNW turn, and there are currently no major deterministic models showing a southern track toward Guam.
Rota
Direct eyewall risk: Very Low to Low
Estimated direct-hit chance: 2–5%
Overall impact risk: Low to Moderate
Trend: Lower
Rota remains substantially south of the favored corridor. A meaningful southward forecast error would be required to bring the core near the island.
Tinian
Direct eyewall risk: Low
Estimated direct-hit chance: 3–7%
Overall impact risk: Low to Moderate
Trend: Lower
Tinian is still south of the main forecast track. The current northward motion further helps compared with the previous WSW movement.
Saipan
Direct eyewall risk: Low to Moderate
Estimated direct-hit chance: 7–12%
Overall impact risk: Moderate
Trend: Slightly lower
Saipan remains the closest major populated island, but JTWC still expects the center to pass approximately 161 miles away. That is a substantial distance, although a large and powerful typhoon could still produce peripheral weather and dangerous seas.
Pagan
Direct eyewall risk: Moderate to High
Overall impact risk: High
Trend: Remains the primary concern
Pagan and the northern CNMI remain much closer to the expected corridor. The exact track as Saudel begins its WNW bend will determine which northern islands face the greatest risk.
Agrihan / Alamagan
Direct eyewall risk: Moderate to High
Overall impact risk: High
These islands remain much more relevant to the current forecast than Guam, Rota or Tinian.

What I’ll Watch in the Next Update
The most important thing is continued latitude gain.
If Saudel continues:
N → NNW → NW
over the next 12–24 hours, confidence should increase that the populated southern Marianas will remain south of the core.
If it unexpectedly stalls or begins moving west again, we’d reassess.
The second thing is organization.
If satellite imagery shows Saudel rapidly becoming symmetrical, that 110-mph Day-2 RI guidance becomes much more interesting, and JTWC may raise the short-term intensity forecast.

Bottom Line
This update is better for Guam, Rota, Tinian and Saipan from a track standpoint.
The temporary WSW movement has ended and Saudel is now moving north, allowing it to gain latitude before the expected WNW turn. Track models are also in good agreement through Day 3, with no major southern outlier currently highlighted.
The primary threat remains the Northern Mariana Islands around Pagan/Alamagan/Agrihan.
But intensity is becoming the bigger story. JTWC forecasts Saudel to become approximately a 145-mph Category 4-equivalent typhoon, and some guidance supports an even stronger system.
So for the next update, I’d focus on two questions: Does Saudel keep gaining latitude, and does rapid intensification begin earlier than JTWC currently expects?

JTWC 17W Update Analysis
Converted to mph and miles for easier reading

Summary
This update is more interesting for the Marianas than Warning #2, mainly because 17W unexpectedly moved west-southwest during the past six hours.
17W is about 161 miles east-northeast of Chuuk.
It moved west-southwest at about 4 mph.
Significant wave height is about 13 feet.
JTWC believes the southwest motion is probably temporary and partly related to the still-forming circulation.
Steering remains very weak, which makes short-term movement less predictable.
A more poleward/north-northwest motion is still expected within about 12 hours.
A westward turn is forecast around 60–72 hours, near the time 17W crosses the Northern Marianas.
Rapid intensification remains forecast from about 36–72 hours.
JTWC expects an increase of at least 60 mph during the RI period.
The eventual peak remains just below super typhoon strength.
Some ensemble members still reach as far south as Rota.
Track confidence remains only medium.

Forecast Change Score: 6.5/10
The long-term forecast philosophy hasn’t changed dramatically.
What’s changed is the actual observed motion.
Previous update:
WNW at ~6 mph
Current update:
WSW at ~4 mph
That’s worth watching because every mile 17W gains south or west before its expected poleward turn can affect where its eventual westward bend intersects the Marianas.
But JTWC is not interpreting this as the beginning of a sustained southwest track.

Why Did 17W Suddenly Move Southwest?
This is an important distinction.
JTWC believes part of what we’re seeing may be caused by the storm’s circulation still consolidating.
The strongest winds are currently concentrated southeast of the developing center. As that area wraps cyclonically around the circulation, it can cause the apparent center to relocate or move southwest.
In other words, some of this may be:
the center reorganizing rather than the entire cyclone being strongly steered southwest.
17W is also still shallow and sitting in a weak steering environment.
That combination makes these little movements much easier.
This is quite different from a mature typhoon being firmly pushed southwest by a strong ridge.

Track and Steering
The next 12–24 hours are particularly important.
Right now, 17W has several weak steering influences competing with one another.
Currently
The shallow cyclone is embedded in an elongated trough providing a weak westward push.
At the same time, a near-equatorial ridge southeast of 17W is building.
That ridge should eventually push 17W more poleward.
JTWC therefore still expects:
WSW now → poleward/NNW within ~12 hours → NW → eventually more westward approaching the Marianas
Around Day 2½–3
This is where things become especially important for the islands.
A subtropical ridge northeast of 17W should build westward.
That effectively closes off the weakness that 17W had been moving toward and causes the cyclone to turn more westward.
JTWC expects that turn to occur around the same time 17W reaches the Northern Marianas.
So where the cyclone is located before that westward turn begins could make a substantial difference.

Rapid Intensification
The RI signal remains strong.
For approximately the next 36 hours, JTWC expects more normal strengthening while:
Wind shear decreases
The circulation becomes more symmetrical
Upper-level outflow improves
Then:
Rapid intensification is forecast from roughly 36–72 hours.
JTWC expects winds to increase by at least 55 knots, equivalent to approximately 63 mph, during that period.
That’s a substantial increase.
Importantly, the expected RI period overlaps with the cyclone’s approach toward the Northern Marianas.
After crossing the island chain, strengthening should slow and eventually plateau just below super typhoon intensity.
So we’re still potentially looking at a major typhoon crossing the northern CNMI.

Model Guidance
The deterministic models remain reasonably well clustered on the overall NNW/NW track.
There are two notable eastern outliers:
JGSM and ECMWF deterministic
They initially take 17W northeast before eventually bending northwest.
That would generally favor a farther-north passage.
But the ensemble spread tells us there is still meaningful uncertainty.
ECENS, ECAIE and GEFS all contain individual members extending as far south as:
Rota
Again, that doesn’t mean Rota is forecast to be hit.
It means the southern edge of the plausible envelope still reaches that far.
One reason for the continued uncertainty is particularly important: JTWC isn’t completely confident in the exact location of the consolidating low-level center yet.
If the starting position changes as the circulation organizes, later model tracks can shift as well.

Island Risk Assessment
My interpretation of this JTWC update, not official probabilities.
Guam
Direct eyewall risk: Very Low to Low
Estimated direct-hit chance: 3–7%
Overall impact risk: Low to Moderate
Trend: Slightly higher
The WSW movement is worth watching, but the official forecast and deterministic consensus remain well north of Guam. Guam would require a substantial southern forecast shift. I wouldn’t raise Guam’s risk dramatically based on this one short-term movement.
Rota
Direct eyewall risk: Low to Moderate
Estimated direct-hit chance: 7–12%
Overall impact risk: Moderate
Trend: Slightly higher
Rota remains near the southern edge of the ensemble envelope. The unexpected WSW motion makes that southern envelope a little more noteworthy, but Rota is still not near the most likely track.
Tinian
Direct eyewall risk: Low to Moderate
Estimated direct-hit chance: 10–18%
Overall impact risk: Moderate
Trend: Slightly higher
Tinian remains south of the favored corridor, but there is enough uncertainty in the initial center position and future westward turn that it deserves continued monitoring.
Saipan
Direct eyewall risk: Moderate
Estimated direct-hit chance: 15–25%
Overall impact risk: Moderate to High
Trend: Roughly unchanged
Saipan remains considerably closer to the favored corridor than Guam or Rota. A modest southward adjustment could become important for Saipan.
Pagan
Direct eyewall risk: High
Overall impact risk: Very High
Trend: Remains highest
The northern CNMI remains the primary threat area under the current JTWC forecast. A major typhoon could be approaching this region in roughly three days.
Agrihan / Alamagan
Direct eyewall risk: Moderate to High
Overall impact risk: High to Very High
These islands remain within the broader northern CNMI threat corridor.

What I’m Watching Now
The next observed movement is probably more important than another small model fluctuation.
JTWC expects 17W to start moving more poleward within about 12 hours.
If we see that happen:
WSW → WNW/NW → NNW
then today’s southwest movement was probably just the temporary reorganization JTWC describes.
If instead 17W continues west or west-southwest for another 12–24 hours, that’s when I would become noticeably more concerned about a future southward track adjustment toward Saipan/Tinian/Rota.
The second thing is the location of the low-level circulation center. Once that consolidates, the models should have a better starting point, and track confidence may improve substantially.

Bottom Line
This update does not mean 17W is suddenly heading toward Guam.
But the unexpected west-southwest movement is worth paying attention to because steering is weak and the circulation is still organizing.
JTWC still expects a poleward turn soon, followed by a northwestward track and eventually a more westward bend across the Northern Mariana Islands.
The primary threat remains Pagan and the northern CNMI, with Saipan next in line.
The next 12–24 hours should tell us a lot: if the forecast poleward motion begins, the current track remains on course. If it doesn’t and 17W keeps drifting west/southwest, the risk assessment for the populated southern islands will need to be raised.

JTWC Warning #2 Analysis – Tropical Cyclone 17W
Converted to mph and miles

Summary
17W is about 192 miles east-northeast of Chuuk.
It has accelerated from about 2 mph to 6 mph, now moving west-northwest.
Significant wave height remains around 12 feet.
Steering is becoming better established, and the system should begin moving north-northwest more decisively.
The forecast now explicitly says 17W will cross the Northern Mariana Islands in about 3–4 days.
Rapid intensification is expected between roughly 36–84 hours.
JTWC expects it to cross the Northern Marianas at over 115 mph.
RI probabilities are very high: 75–90% from COAMPS-TC and over 75% from Google DeepMind.
Importantly, the previous extreme model outliers have moved toward the main model cluster.
However, ensemble members still extend as far south as Rota.

Forecast Change Score: 7/10
Warning #2 is a meaningful change from #1.
The biggest development isn’t necessarily a dramatic southward shift. It’s that the forecast has evolved from:
“Pass about 161 miles north of Saipan near Pagan”
to:
“Cross over the Northern Mariana Islands.”
That increases concern for the northern CNMI.
At the same time, model agreement has actually improved.

What Changed From Warning #1?
Track
Warning #1:
Forecast passage about 161 miles north of Saipan
Near Pagan
HAFS-A was a major southern outlier between Rota and Tinian
ECMWF was the major northern outlier
Warning #2:
Forecast explicitly says cross the Northern Mariana Islands
HAFS-A has moved north toward the consensus
ECMWF has moved south toward the consensus
Most deterministic models are now much more tightly grouped
Ensemble members still extend southward to Rota
That’s actually an important improvement in forecast consistency.
Instead of two models pulling in opposite directions, the main guidance is beginning to converge.

Steering Pattern
The steering setup has also changed somewhat from Warning #1.
Next 12–36 hours
A near-equatorial ridge southeast of 17W should push it north-northwest.
Meanwhile, the subtropical ridge north-northwest of the storm retreats.
That gives 17W an opportunity to gain latitude.
In simple terms:
The storm should start climbing north.
Around 60–72 hours
Then another subtropical ridge builds westward from the northeast.
That ridge should prevent 17W from simply continuing north.
Instead, it should bend the track slightly back toward the west.
So the expected motion is approximately:
WNW now → NNW → slightly more westward/NW approaching the Marianas
That final westward bend is important because it brings the cyclone across the Northern Mariana Islands.

Rapid Intensification Risk
This is probably the biggest concern in Warning #2.
JTWC now has high confidence in the intensity forecast through Day 3.
For roughly the next 36 hours, strengthening should remain relatively slow.
Then conditions improve significantly:
Wind shear decreases
Dry air becomes less influential
Poleward outflow improves
Ocean temperatures remain extremely warm
JTWC explicitly forecasts rapid intensification between 36 and 84 hours.
And the model probabilities are unusually strong:
COAMPS-TC: 75–90% chance of RI
Google DeepMind: greater than 75% chance of RI
JTWC expects the storm to cross the Northern Marianas with winds exceeding:
115 mph
That’s already Category 3-equivalent intensity.
And because RI can sometimes outperform forecasts—as we just saw with Bavi—I’d pay close attention to subsequent intensity forecasts.

Model Guidance
There’s actually some encouraging news here for the populated southern Marianas.
HAFS-A
Yesterday this was the concerning model.
It showed a track:
between Tinian and Rota.
Now HAFS-A has moved toward the main model grouping.
That’s significant.
ECMWF
ECMWF was previously the northernmost model, taking 17W almost straight north initially.
It has also moved toward the consensus.
So the two major outliers from Warning #1 have converged toward the middle.
Ensembles
This is where uncertainty remains.
GEFS, ECENS and ECMWF-AIFS ensemble systems still contain individual members reaching as far south as Rota.
That does NOT mean the ensemble forecast is for Rota.
It means a southern solution remains meteorologically possible.

Island Risk Assessment
My interpretation of Warning #2, not official JTWC probabilities.
Guam
Direct eyewall risk: Very Low
Estimated direct-hit chance: 2–5%
Overall impact risk: Low to Moderate
Trend from Warning #1: Slightly lower
Assessment: The deterministic model consensus has improved well north of Guam. Some ensemble members extend toward Rota, but Guam remains substantially south of the main forecast corridor.
Rota
Direct eyewall risk: Low
Estimated direct-hit chance: 5–10%
Overall impact risk: Moderate
Trend from Warning #1: About the same
Assessment: Rota remains on the extreme southern side of the ensemble envelope. A direct hit is not currently favored, but the fact that some ensemble members reach Rota means it is too early to dismiss.
Tinian
Direct eyewall risk: Low to Moderate
Estimated direct-hit chance: 8–15%
Overall impact risk: Moderate
Trend from Warning #1: About the same
Assessment: Tinian remains south of the main guidance cluster, although a significant southward forecast error could bring the system closer.
Saipan
Direct eyewall risk: Moderate
Estimated direct-hit chance: 15–25%
Overall impact risk: Moderate to High
Trend from Warning #1: Slightly higher
Assessment: Saipan is closer to the developing forecast corridor. The official track still appears north of Saipan, but the wording has changed from passing well north to crossing the Northern Marianas.
Pagan
Direct eyewall risk: High
Estimated direct-hit chance: 35–50%
Overall impact risk: Very High
Trend from Warning #1: Remains highest
Assessment: Pagan and the surrounding northern islands remain closest to the expected track and currently face the greatest risk of the core passing nearby.
Agrihan / Alamagan
Direct eyewall risk: Moderate to High
Overall impact risk: High to Very High
Assessment: The developing Northern Marianas track puts these islands within the area that deserves particularly close monitoring.

What I’ll Watch for in Warning #3
There are three things that matter most now.
First: Does the model consensus shift north or south?
The convergence of HAFS-A and ECMWF is a good sign for forecast confidence. If the entire cluster begins moving south, however, Saipan/Tinian risk would increase quickly.
Second: Where does the westward bend begin?
If the subtropical ridge builds earlier or stronger than expected, 17W could turn west sooner and potentially track farther south through the Marianas.
If it gains more latitude before that happens, the threat remains focused farther north.
Third: Does RI begin earlier than expected?
The RI probabilities are already very high. If satellite observations start showing rapid organization during the next 24–36 hours, the intensity forecast could rise considerably.

Bottom Line
Warning #2 strengthens the case for a significant typhoon affecting the Northern Mariana Islands in roughly 3–4 days.
The good news for Guam, Rota and Tinian is that the concerning southern HAFS-A outlier has moved back toward the main model cluster.
The concerning development is intensity: JTWC now has high confidence through Day 3, with a 75–90% RI signal and a forecast of 115+ mph winds when 17W crosses the Northern Marianas.
Right now, Pagan and the northern CNMI are the primary concern, with Saipan next. Guam remains well south of the most likely track.
The track is becoming clearer—but with medium track confidence, a somewhat uncertain initial position, and 3–4 days remaining, it’s still too early to consider the southern Marianas completely out of play.

Super Typhoon Bavi - Final JTWC Analysis
Based on JTWC Warning #21, converted to mph and miles

Summary
Bavi is now transitioning away from the Mariana Islands after passing through the Rota/Tinian corridor.
The storm remains a very powerful super typhoon, but the main focus of the forecast is now shifting west-northwest of the Marianas toward the western Pacific, with longer-range questions involving Okinawa, Taiwan, and the subtropical ridge pattern.
Key points:
Bavi is about 1,394 miles southeast of Kadena Air Base.
It tracked west-northwest over the past 6 hours at about 12 mph.
Maximum significant wave height remains around 54 feet.
The west-northwest motion is now established.
A secondary eyewall appears to be forming, which adds uncertainty to short-term intensity.
Brief weakening is possible first, followed by another chance of intensification in about 36 hours.
Bavi will remain a very large typhoon, so impacts can continue far from the center even as the core moves away.

Final Forecast Change Score for the Marianas: 4/10
This is not a major new local track change for Guam, Rota, Tinian, or Saipan.
Instead, this update confirms that Bavi is moving away from the immediate Mariana Islands threat phase and the forecast discussion is now focused more on the next part of the track.
The biggest takeaways are:
The storm continued west-northwest.
The direct Guam threat has dropped significantly.
Rota and Tinian were the main core-impact zone.
The wind field remains large, so lingering impacts are still possible.
The forecast focus is now shifting toward the western Pacific.

What Changed From Warning #20?
Warning #20 was the critical local-impact update. It placed Bavi about 61 miles east of Rota and showed a very tight track near Rota.
Warning #21 no longer focuses on distance from Rota or Guam. Instead, it references distance from Kadena Air Base, which shows the forecast discussion is shifting downstream.
That usually means the storm has moved through or is moving away from the immediate Mariana Islands corridor.
The main new meteorological detail is the forming secondary eyewall, which means Bavi may be going through another structural change.

Track and Steering
Bavi is now moving west-northwest at about 12 mph.
The subtropical ridge remains the main steering force. The ridge is pushing the storm west-northwest away from the Marianas.
Later in the forecast period, Bavi may turn more poleward, but JTWC says the model preference still favors a shallower track toward the northern Taiwan area rather than a sharp recurve.
For the Marianas, the important part is this:
Bavi’s WNW motion is established, and the direct threat is moving away.

Intensity and Eyewall Replacement
Bavi remains very powerful, but the intensity forecast is complicated.
JTWC says recent microwave imagery shows a forming secondary eyewall. That usually means an eyewall replacement cycle may be starting or trying to start.
That can lead to:
Temporary weakening
A larger eye
A broader wind field
Strong winds spreading farther from the center
Possible re-intensification after the cycle finishes
JTWC expects a brief weakening phase first, then possible renewed strengthening in about 36 hours if outflow improves again.
Model Guidance
Track guidance remains fairly good over the next 3 days, but the longer range becomes more uncertain.
Cross-track spread at 3 days: 204 km / about 127 miles
Cross-track spread by the end of the forecast period: 630 km / about 391 miles
That longer-range uncertainty matters more for areas west and northwest of the Marianas.
For Guam and the CNMI, the main local track story is mostly complete.

Final Bottom Line
Bavi’s direct threat to the Mariana Islands is now transitioning out.
The storm did not become a direct Guam landfall scenario. The worst core threat focused near Rota and Tinian, with Rota being the highest-risk island during the closest approach.
For Guam, especially northern Guam, this was still a serious wind event, but the direct eyewall risk has dropped significantly now that Bavi is moving west-northwest away from the islands.
The final concern for the Marianas is lingering impacts: strong gusts, rain bands, rough seas, dangerous surf, and power-related issues. But the main focus of the forecast is now shifting away from the Marianas and toward the western Pacific.

Thank you to everyone who followed along with the Bavi updates. I appreciate all the comments and shared information throughout this monster storm.

JTWC Warning #20 Analysis – Super Typhoon Bavi
Converted to mph and miles

Summary
Bavi is now only about 61 miles east of Rota.
It has tracked west-northwest over the past 6 hours at about 9 mph.
Maximum significant wave height is about 54 feet.
The storm is now very close to the Mariana Islands.
Track guidance is extremely tight near Rota, with only about 9 miles of cross-track spread at closest approach.
Bavi is expected to pass very near or over Rota.
The storm may briefly weaken, then intensify again over the next 36 hours.
HAFS still shows possible peak intensity around 168–174 mph.
The wind field is very large, so impacts will extend far from the center.

Forecast Change Score: 7.5/10
This is a serious confirmation update more than a surprise shift.
The biggest changes from Warning #19 are:
Bavi is now only 61 miles east of Rota.
The track guidance near Rota is now extremely tight.
The closest approach uncertainty to Rota is only about 9 miles.
The forecast continues to strongly favor a near-direct impact on Rota.
Guam’s direct-eyewall risk is lower than Rota, but northern Guam remains at risk for damaging winds.
Tinian remains very close to the dangerous core zone.

What Changed From Warning #19?
Warning #19 said the forecast track shifted south and brought the center directly over or very near Rota.
Warning #20 now confirms Bavi is very close to that scenario.
The most important line is:
Cross-track spread of only 15 km during closest approach to Rota.
That is only about 9 miles.
That means the model guidance is tightly locked in on a very close Rota passage. At this point, small wobbles matter more than big model shifts.

Steering Pattern
Bavi is still being steered west-northwest by the rebuilding subtropical ridge.
Earlier, the big question was whether the storm would stay west too long or turn WNW.
Now, the WNW motion is established.
The ridge is pushing Bavi through the Mariana Islands on a west-northwest track. That keeps the highest core risk focused near Rota, with Tinian also very close to the danger zone.

Intensity
JTWC expects a brief weakening phase because of reduced upper-level outflow.
After about 12 hours, Bavi may deepen again as a westward outflow channel improves.
HAFS shows possible intensification to:
270–280 km/h
145–150 knots
168–174 mph
So even with brief weakening, Bavi remains an extremely powerful typhoon near the islands.

Model Guidance
Track confidence near the Marianas is now very strong.
Cross-track spread near Rota: 15 km / 9 miles
Cross-track spread at 3 days: 120 km / 75 miles
Along-track spread at 3 days: 222 km / 138 miles
Extended range spread by 5 days: 500 km / 311 miles
For the Marianas, the near-term number is what matters most: 9 miles near Rota. That is very tight.

Island Risk Assessment
Personal interpretation based on JTWC Warning #20. Not official probabilities.

Guam
Direct eyewall risk: Low
Estimated direct-hit chance: 2–6%
Overall impact risk: High to Very High
Trend from previous update: Direct-hit risk slightly lower, wind-impact risk still high
Assessment: Guam is not the most likely location for the eyewall center anymore. The track is now tightly focused near Rota. However, northern Guam is still close enough to experience damaging winds, especially gusts. Strong tropical-storm conditions are likely, and typhoon-force gusts remain possible in northern Guam depending on the size of the eyewall and southern wind field.

Rota
Direct eyewall risk: Extreme
Estimated direct-hit chance: 75–90%
Overall impact risk: Extreme
Trend from previous update: Higher confidence
Assessment: Rota is the main impact point in this update. Bavi is only about 61 miles east of Rota, and the model spread near closest approach is only about 9 miles. This is a very dangerous near-direct or direct impact setup.

Tinian
Direct eyewall risk: High to Very High
Estimated direct-hit chance: 35–50%
Overall impact risk: Extreme
Trend from previous update: Still very high
Assessment: Tinian remains very close to the core corridor. If Bavi passes just north of Rota or wobbles slightly north, Tinian could experience much stronger conditions. Even without a direct eyewall pass, dangerous winds are likely.

Saipan
Direct eyewall risk: Moderate to High
Estimated direct-hit chance: 20–35%
Overall impact risk: Very High
Trend from previous update: About the same
Assessment: Saipan is farther north of the current Rota-focused track, but the storm’s expanding wind field keeps Saipan in serious risk for damaging winds, heavy rain, dangerous surf, and power outages.
What This Means for Guam Winds
With the center focused near Rota, Guam is south of the main core path. That helps reduce the chance of the full eyewall over Guam.
Current Guam estimate:

Guam overall
Sustained winds: 50–75 mph
Gusts: 75–100 mph
Northern Guam / Andersen side
Sustained winds: 65–90 mph possible
Gusts: 95–120 mph possible
If the eyewall expands south or wobbles closer
Sustained winds: 90+ mph possible in northern Guam
Gusts: 120+ mph possible
The worst core winds are still most likely near Rota, not Guam.

Bottom Line
Warning #20 strongly confirms that Rota is the highest-risk island for a direct or near-direct core impact.
For Guam, the direct-eyewall risk is lower than it was during the westward wobble concern, but this is still a serious wind event, especially for northern Guam. Guam should expect significant impacts even without taking the center.
The key now is no longer long-range model shifts. It is short-term wobble watching. With Bavi only about 61 miles east of Rota, even a small north or south wobble can make a major difference for Rota, Tinian, and northern Guam.

JTWC Warning #19 Analysis – Super Typhoon Bavi

Converted to mph and miles

Summary
Bavi is about 135 miles east of Andersen AFB.
It tracked west-northwest over the past 6 hours at about 14 mph.
Maximum significant wave height is about 52 feet.
A recent due west jog increased the chance of a direct landfall on or very near Rota.
JTWC shifted the 12–24 hour forecast track south by about 23 miles.
The forecast now brings the center directly over Rota.
Bavi is at or near peak intensity and will remain very powerful through the Marianas passage.
The storm is expanding, so impacts will extend far from the center.
Track confidence is medium after 24 hours, but the short-term Rota threat is now much higher.

Forecast Change Score: 8/10
This is a major short-term change.
The biggest changes from Update #18 are:
Bavi made an unexpected westward jog.
JTWC shifted the short-term track southward.
The forecast now brings the center directly over Rota.
Guam’s wind risk increases, especially northern Guam.
Rota is now the clear highest-risk location for direct core impact.
Tinian’s direct-eyewall risk decreases slightly compared with Update #18, but remains very high.
Saipan’s direct-eyewall risk decreases somewhat, but impacts are still likely because of the large wind field.

What Changed From Update #18?

Track
Update #18 had Bavi moving northwestward with a slight northward adjustment.
Update #19 now says a recent due west motion forced JTWC to shift the short-term track south by 20 nautical miles, or about 23 miles.
That is very important because a 20–25 mile shift matters a lot when the core is near Rota, Tinian, and Guam.
The key line is:
The forecast track brings the center directly over Rota.
That is the strongest Rota-focused wording so far.

Motion
Bavi is still officially listed as moving west-northwest, but JTWC notes a recent due west shift.
So the main idea is:
Overall motion: WNW
Recent short-term wobble: due west
Forecast response: shifted south toward Rota
This is why Guam’s risk has gone back up compared with Update #18.

Steering Pattern
Bavi is still expected to resume a west-northwest track shortly, steered by a deep-layer subtropical ridge to the north.
But the problem is timing.
Even a short due-west wobble this close to the islands can shift the closest approach south enough to make a big difference.
Simple version:
The ridge is still expected to steer Bavi WNW.
But Bavi jogged west at a bad time.
That shifted the core closer to Rota and closer to Guam.
The next few hours matter a lot.

Intensity
JTWC says Bavi is at or very near peak intensity.
The environment remains extremely favorable:
Very high ocean heat content
Low wind shear
Strong divergence aloft
Abundant moisture
Weakening should begin after about 24 hours, but that likely happens after the most important Marianas impacts begin.
So for Rota/Tinian/Guam, Bavi is still approaching as an extremely powerful typhoon.

Wind Field
This is a major concern.
Bavi is expanding, with gale-force winds forecast to extend nearly:
556 km
345 miles
from the center later in the forecast period.
JTWC also says this large size may help protect the core from wind shear.
For Guam, this means the island does not need a direct landfall to experience serious winds. A Rota landfall is close enough to bring strong impacts to Guam, especially northern Guam.

Model Guidance
Model agreement is still good for the next 3 days.
3-day cross-track spread: 176 km / about 109 miles
4-day spread: 426 km / about 265 miles
5-day spread: 593 km / about 368 miles
JTWC placed the forecast along the southern edge of the guidance envelope for the first 12–24 hours to account for the unexpected westward motion.
That means they are intentionally correcting south in the short term.

Island Risk Assessment
Personal interpretation based on JTWC Warning #19. Not official probabilities.

Guam
Direct eyewall risk: Low to Moderate
Estimated direct-hit chance: 8–15%
Overall impact risk: High to Very High
Trend from previous update: Higher
Assessment: Guam’s direct-eyewall risk increases because the track shifted south and the center is now forecast directly over Rota. Guam is still not the most likely landfall location, but northern Guam is close enough that typhoon-force gusts are becoming more realistic. Strong tropical-storm conditions are likely, and northern Guam could see periods of damaging typhoon-force winds if the core expands or the track wobbles farther south.

Rota
Direct eyewall risk: Extreme
Estimated direct-hit chance: 65–80%
Overall impact risk: Extreme
Trend from previous update: Much higher
Assessment: Rota is now the clear highest-risk location. JTWC specifically shifted the track south and brings the center directly over the island. This is a very dangerous direct-impact setup for Rota.

Tinian
Direct eyewall risk: High to Very High
Estimated direct-hit chance: 30–45%
Overall impact risk: Extreme
Trend from previous update: Slightly lower
Assessment: Tinian remains very close to the core corridor, but the southward adjustment places the center closer to Rota than Tinian. A small north wobble would quickly raise Tinian’s direct-eyewall risk again.

Saipan
Direct eyewall risk: Moderate
Estimated direct-hit chance: 15–30%
Overall impact risk: Very High
Trend from previous update: Lower for direct eyewall
Assessment: Saipan’s direct-eyewall risk decreases with the southward shift, but the island is still close enough to experience serious impacts from the expanding wind field, heavy rain, dangerous surf, and possible damaging gusts.

What Guam Could Feel Now
With the center forecast over or near Rota, Guam’s wind potential is higher than it looked in Update #18.

Most likely Guam wind range
Sustained winds: 50–75 mph
Gusts: 75–100 mph
Northern Guam / Andersen side
Sustained winds: 65–90 mph possible
Gusts: 95–120 mph possible
If the track wobbles farther south or the eyewall expands
Sustained winds: 90+ mph possible in northern Guam
Gusts: 120+ mph possible
The full peak winds near Bavi’s core are still most likely around Rota, not Guam, unless the eyewall expands southward or the center tracks farther south.

Bottom Line
Warning #19 is a serious southward adjustment.
The forecast now brings Bavi’s center directly over Rota, making Rota the clear highest-risk island for direct core impacts.
For Guam, this update is more concerning than Update #18. Guam is still not the most likely direct landfall point, but a Rota landfall is close enough that northern Guam could experience damaging typhoon-force gusts, especially if the wind field expands or the storm wobbles slightly farther south.
The next short-term motion is critical. If Bavi resumes steady WNW soon, the core stays focused near Rota/Tinian. If it continues due west longer, Guam’s risk increases further.

JTWC Warning #18 Analysis – Super Typhoon Bavi

Converted to mph and miles

Summary
Bavi is about 216 miles east of Andersen AFB.
It tracked northwestward over the past 6 hours at about 10 mph.
Maximum significant wave height is about 48 feet.
Bavi has made a northward jog over the past 6 hours.
JTWC shifted the forecast track slightly north/poleward for the next 12–36 hours.
Nearly all guidance still takes the center between Rota and Tinian.
Track confidence is now high near the multi-model consensus.
Bavi is in an extremely favorable environment for more near-term intensification.
The wind field is expanding, with gale-force winds forecast to extend nearly 345 miles from the center later in the forecast period.

Forecast Change Score: 7/10
This is a meaningful update because the storm moved northwestward and the forecast track was adjusted northward.
The biggest changes from Update #17 are:
Bavi is moving faster.
Bavi made a northward jog.
The forecast track shifted slightly north for the next 12–36 hours.
Guam’s direct-eyewall risk decreases.
Tinian’s direct-eyewall risk increases.
Rota remains in very serious danger.
Saipan’s risk increases slightly because of the poleward adjustment and expanding wind field.

What Changed From Update #17?

Track
Update #17 had Bavi moving west-northwest at about 8 mph.
Update #18 now says Bavi tracked northwestward at about 10 mph.
That is a noticeable northward component.
JTWC specifically says there was a northward jog within the past 6 hours, and because of that, the forecast was adjusted slightly poleward in the 12–36 hour period.
This is better news for Guam’s direct-hit risk, but it increases concern for Tinian and keeps Rota in the danger zone.

Forecast Path
The most important track line is:
Nearly all guidance takes the storm center between Tinian and Rota.
So this is not a major escape north. The core is still aimed through the southern CNMI corridor.

Steering Pattern
Bavi is now moving toward the influence of a strong subtropical ridge centered near the Ryukyu Islands.
The current steering setup is doing two things:
Near term: It allows Bavi to move WNW/NW toward the Marianas.
After 1.5 to 3 days: The ridge flattens the track more westward.
For the Marianas, the near-term part matters most.
The northward jog means the storm has moved away from the worst-case Guam scenario, but it has not turned far enough north to spare Rota or Tinian.

Intensity
The environment is becoming even more favorable.
JTWC mentions:
Better westward and poleward outflow
Very high ocean heat content
Sea surface temperatures around 86–88°F
Increasing upper-level divergence
That combination can support additional intensification as Bavi approaches and passes the southern Marianas.
HAFS-A remains the most aggressive model, showing a possible peak of:
285–295 km/h
155–160 knots
about 177–183 mph
JTWC also says a peak higher than the official forecast is possible.
The main uncertainty is still the eyewall replacement cycle. If an eyewall replacement cycle starts or continues, it can temporarily weaken the storm, but it can also make the wind field larger.

Wind Field
This remains one of the biggest concerns.
Bavi’s circulation is expanding, and later in the forecast period gale-force winds may extend nearly:
556 km
345 miles
from the center.
For the Marianas, this means impacts will extend far from the eye. Even if Guam avoids the eyewall, strong winds, heavy rain, coastal flooding, dangerous surf, and power outages remain possible.

Model Guidance
Track guidance remains tightly clustered for the next 3 days.
3-day cross-track spread: 204 km / about 127 miles
5-day spread: 417 km / about 259 miles
JTWC says nearly all guidance takes the center between Tinian and Rota, and the official track is placed with high confidence near the model consensus.
That high confidence near the Marianas makes this update more serious for Rota and Tinian.

Island Risk Assessment
Personal interpretation based on JTWC Warning #18. Not official probabilities.

Guam
Direct eyewall risk: Low
Estimated direct-hit chance: 3–8%
Overall impact risk: High
Trend from previous update: Lower
Assessment: Guam’s direct-eyewall risk decreases because Bavi made a northward jog and the forecast track shifted slightly poleward. Guam is no longer favored for a direct core hit in this update. However, Guam is still close enough to experience strong tropical storm conditions, possible typhoon-force gusts, heavy rain, dangerous surf, and power outages.

Rota
Direct eyewall risk: Very High
Estimated direct-hit chance: 40–55%
Overall impact risk: Extreme
Trend from previous update: Still very high
Assessment: Rota remains in a very dangerous position. The track is still between Rota and Tinian, so Rota is still close to the expected core passage. The northward jog may reduce the chance of a direct pass over Rota compared with a more southern track, but Rota remains one of the highest-risk islands.

Tinian
Direct eyewall risk: Very High
Estimated direct-hit chance: 45–60%
Overall impact risk: Extreme
Trend from previous update: Higher
Assessment: Tinian’s risk increases in this update because of the northward jog and poleward track adjustment. Nearly all guidance still takes the center between Rota and Tinian, putting Tinian very close to the expected core corridor.

Saipan
Direct eyewall risk: Moderate to High
Estimated direct-hit chance: 25–40%
Overall impact risk: Very High to Extreme
Trend from previous update: Slightly higher
Assessment: Saipan’s risk increases slightly because the track shifted north and Bavi’s wind field is expanding. Saipan is still north of the main Rota/Tinian corridor, but a small additional northward wobble or larger eyewall/wind field could bring much stronger conditions.

Bottom Line
Update #18 is better for Guam from a direct-hit standpoint. Bavi made a northward jog, is moving faster, and JTWC shifted the track slightly north.
The highest-risk corridor is now clearly between Rota and Tinian, with Tinian’s risk increasing and Rota still in extreme danger.

Guam is less likely to take the eyewall, but impacts are still likely because Bavi is large, intense, and expanding. The main thing to watch now is whether the northwest jog continues or whether the ridge flattens the track back more westward as JTWC expects in 1.5 to 3 days.

JTWC Update 17 Analysis – Super Typhoon Bavi

Converted to mph and miles

Summary
Bavi is about 291 miles east of Naval Base Guam.
It tracked west-northwest over the past 6 hours at about 8 mph.
Maximum significant wave height remains around 45 feet.
The west-northwest motion is now becoming more established.
The subtropical ridge northeast of Bavi is becoming the main steering force.
Bavi is expected to continue west-northwest toward the Mariana Islands.
Track guidance remains very tight near closest approach, with only about 42 miles of cross-track spread near Tinian and Rota.
Peak intensity is forecast around 160 mph, with some high-resolution guidance showing 160–167 mph.
The wind field is expected to become very large, with impacts extending far from the center.

Forecast Change Score: 5.5/10
This is not a huge track change, but it is an important confirmation update.
The biggest changes are:
Bavi is now officially moving west-northwest again.
The steering ridge is becoming more established.
The expected acceleration should begin.
The near-term track confidence remains strong.
Guam’s direct-eyewall risk decreases slightly.
Rota and Tinian remain the main danger corridor.

What Changed From Update 16?

Track
Update 16 was concerning because Bavi had stayed west longer than expected, which shifted the track southwest and closer to Rota.
Update 17 now says Bavi tracked west-northwest over the past 6 hours.
That is important.
It means the delayed WNW turn appears to be happening now. This is somewhat better for Guam compared with continued westward motion.

Steering
The ridge northeast of Bavi is now becoming the primary steering force. That supports continued west-northwest movement instead of more west or west-southwest movement.
Simple version:
The westward delay was the concern.
The WNW motion is now resuming.
That reduces the chance of a Guam direct eyewall hit.
The main core risk remains around Rota and Tinian.

Intensity
JTWC forecasts Bavi to temporarily plateau, then possibly reach a secondary peak of around:
260 km/h
140 knots
about 160 mph
Some high-resolution guidance shows a possible peak of:
260–270 km/h
140–145 knots
about 160–167 mph
So this update is slightly less extreme than earlier forecasts that mentioned possible 175–190 mph peaks, but it is still a very dangerous super typhoon.
Another eyewall replacement cycle is still possible around 60 hours, but increasing wind shear may also begin a gradual weakening phase.

Wind Field
This remains a major concern.
JTWC again emphasizes a massively expanded wind field, eventually stretching from near the northern Philippines to Okinawa.
For the Marianas, this means impacts can occur far from the center. Even if an island avoids the exact eyewall, damaging winds, heavy rain, dangerous surf, and power issues are still possible.

Model Guidance
The model track guidance is tightly grouped for the next 3 days.
Cross-track spread near closest approach to Tinian/Rota: 67 km / about 42 miles
Extended-range spread later: 220 km / about 137 miles
That tight near-term spread means forecasters have a fairly focused idea of where the core will pass near the Marianas.
The center is still expected near the Rota/Tinian corridor.

Island Risk Assessment
Personal interpretation based on JTWC Update 17. Not official probabilities.

Guam
Direct eyewall risk: Low to Moderate
Estimated direct-hit chance: 6–12%
Overall impact risk: High
Trend from previous update: Slightly lower
Assessment: Guam’s direct-eyewall risk decreases slightly because Bavi is now moving west-northwest and the steering ridge is becoming established. That is better than continued westward movement. However, Guam remains close enough for strong tropical-storm conditions, possible typhoon-force gusts, heavy rain, dangerous surf, and power problems.

Rota
Direct eyewall risk: Very High
Estimated direct-hit chance: 45–60%
Overall impact risk: Extreme
Trend from previous update: Still very high
Assessment: Rota remains one of the highest-risk islands. The core corridor is still very close to Rota and Tinian, and the model spread is tight. Even a small wobble could determine whether Rota gets the eyewall or the strongest part passes just north or south.

Tinian
Direct eyewall risk: High to Very High
Estimated direct-hit chance: 35–50%
Overall impact risk: Extreme
Trend from previous update: Slightly higher
Assessment: Tinian’s risk increases slightly compared with the previous Rota-focused update because the WNW motion is becoming established. The forecast corridor is now more clearly between Rota and Tinian again.

Saipan
Direct eyewall risk: Moderate to High
Estimated direct-hit chance: 20–35%
Overall impact risk: Very High
Trend from previous update: Slightly higher
Assessment: Saipan remains north of the main core corridor, but the WNW motion and large wind field keep Saipan at serious risk. A slight northward wobble or expanded eyewall/wind field could bring much stronger conditions.

Bottom Line
Update 17 is somewhat better for Guam from a direct-hit standpoint because Bavi is now officially moving west-northwest, and the steering ridge is becoming established.

The highest-risk corridor remains Rota and Tinian.
Rota is still in a very dangerous position, but Tinian’s risk is also rising again now that the WNW motion is more established. Saipan remains at serious risk because of the storm’s size and possible northward wobbles.

The main thing to watch now is whether Bavi continues a steady west-northwest track or wobbles back west. If the WNW motion holds, Guam’s direct-hit risk should continue to slowly decrease, while Rota and Tinian remain the primary concern.

JTWC Latest Update Analysis – Super Typhoon Bavi
Converted to mph and miles
Summary
Bavi is about 339 miles east of Naval Base Guam.
It tracked west over the past 6 hours at about 7 mph.
Maximum significant wave height remains around 45 feet.
The storm has slowed more than expected and has only just begun turning west-northwest.
The latest forecast track shifted about 17 miles southwest compared with 24 hours ago.
The center is now forecast to pass much closer to Rota than Tinian.
Track guidance is very tight, with only about 46 miles of cross-track spread near closest approach to Tinian and Rota.
Peak intensity forecast is now around 160–167 mph, slightly lower than the previous higher-end forecast near 175 mph.
Bavi is expected to remain a very strong typhoon with a very large wind field.
Forecast Change Score: 7/10
This is a meaningful update because the forecast track shifted southwest and now focuses more directly on Rota.
The biggest changes are:
Bavi moved west, not clearly west-northwest yet.
It slowed longer than expected.
The forecast shifted 17 miles southwest compared with 24 hours ago.
The center is now expected to pass much closer to Rota than Tinian.
Guam’s direct-eyewall risk increases slightly, but Rota is now the main concern.
Peak intensity forecast is slightly lower, but still extremely dangerous.
What Changed From the Previous Update?
Track
The previous update suggested Bavi had started moving west-northwest and the track nudged slightly poleward.
This update walks that back somewhat.
Now JTWC says Bavi tracked west over the past 6 hours and only just appears to be turning west-northwest. Because it stayed west longer than expected, the forecast track shifted southwest by about 17 miles compared with 24 hours ago.
That matters because a westward motion favors a track closer to Rota and Guam, while an earlier west-northwest turn would favor Tinian and Saipan.
Closest Approach
The forecast now takes the low-level center much closer to Rota than Tinian.
That is the most important line in this update.
Steering Pattern
Bavi is still being steered by the subtropical ridge to the northeast/north.
The passing trough to the north split the broad ridge and weakened the steering flow. That caused Bavi to slow down and continue mostly west longer than expected.
Now, as the ridge to the northeast builds, Bavi should begin gaining speed and turn west-northwest toward the Marianas.
Simple version:
Bavi stayed west longer than expected.
That shifted the track southwest.
The WNW turn is still expected, but it has been slow to fully begin.
This increases concern for Rota and keeps Guam in the risk area.
Intensity
The official peak intensity forecast is now around:
260 km/h / 140 kt / about 160 mph
Some high-resolution models show:
260–270 km/h / 140–145 kt / about 160–167 mph
That is slightly lower than some previous forecasts near 175 mph, but it is still an extremely dangerous Category 5-level typhoon near the core.
JTWC expects some slight intensification due to improved outflow, but increasing wind shear after about 60 hours should eventually cause weakening.
Wind Field
This update again emphasizes that Bavi will have a very large wind field.
JTWC says the wind field may eventually extend from near the northern Philippines to Okinawa. That means this is not a small, compact storm.
For the Marianas, this means impacts can occur far from the center. A direct eye passage is not required for damaging conditions.
Model Guidance
Track guidance is very tight.
Cross-track spread near closest approach: 74 km / about 46 miles
Track confidence appears high near the Marianas.
The official track shifted 17 miles southwest compared with 24 hours ago.
The current forecast favors a center passage very close to Rota.
That tight model spread makes this update more concerning for Rota because the models are not widely scattered anymore.
Island Risk Assessment
Personal interpretation based on this JTWC update. Not official probabilities.
Guam
Direct eyewall risk: Low to Moderate
Estimated direct-hit chance: 10–18%
Overall impact risk: High
Trend from previous update: Slightly higher
Assessment: Guam is still not the most likely direct-eyewall location, but the westward motion lasting longer than expected and the southwest track shift increase concern. Northern Guam especially should continue preparing for strong tropical-storm conditions, possible typhoon-force gusts, heavy rain, dangerous surf, and power issues.
Rota
Direct eyewall risk: Very High
Estimated direct-hit chance: 50–65%
Overall impact risk: Extreme
Trend from previous update: Higher
Assessment: Rota is now the main island of concern. JTWC specifically says the center is forecast to pass much closer to Rota than Tinian. This is a very serious situation for Rota.
Tinian
Direct eyewall risk: High
Estimated direct-hit chance: 25–40%
Overall impact risk: Very High to Extreme
Trend from previous update: Lower than before, but still serious
Assessment: Tinian remains at high risk, but the latest southwest shift places the core closer to Rota. A small northward wobble or larger wind field could still bring severe impacts to Tinian.
Saipan
Direct eyewall risk: Moderate to High
Estimated direct-hit chance: 15–30%
Overall impact risk: Very High
Trend from previous update: Slightly lower
Assessment: Saipan’s direct-eyewall risk is lower than Rota and Tinian in this update, but it remains close enough to the danger zone that serious impacts are still possible, especially if the wind field expands or the track shifts north again.
Bottom Line
This update is more concerning for Rota and Guam than the previous one because Bavi stayed west longer than expected and the forecast shifted about 17 miles southwest.
The official track now takes the center much closer to Rota than Tinian, making Rota the current highest-risk island for a direct eyewall passage.
For Guam, a direct hit is still not the most likely scenario, but the risk has increased slightly. The storm’s slow westward motion is exactly what forecasters warned could bring the track closer to Guam and Rota.
The key thing to watch next is whether Bavi finally commits to a steady west-northwest motion. If it does, Guam’s direct-hit risk should stabilize. If it continues west longer, Guam and Rota risk will increase further.

JTWC Latest Update Analysis – Super Typhoon Bavi

Converted to mph and miles for easier reading

Summary
Bavi is about 362 miles east of Andersen AFB.
It has tracked west-northwest over the past 6 hours at about 7 mph.
Maximum significant wave height is about 45 feet.
The expected west-northwest turn has now begun.
JTWC nudged the forecast track slightly north/poleward compared with the previous update.
The forecast still takes the center between Rota and Tinian.
Track confidence is now medium, not high.
Bavi is likely undergoing a partial eyewall replacement cycle, which may cause short-term weakening.
Re-intensification is expected after the eyewall cycle completes.
Forecast peak remains around 175 mph, with a possible higher peak near 183–190 mph not ruled out.
Bavi is expected to become a very large circulation, with impacts extending far from the center.

Forecast Change Score: 6/10
This is a meaningful update.
The biggest changes are:
The WNW motion has started.
The track was nudged slightly north/poleward.
The center is still forecast between Rota and Tinian.
Guam’s direct eyewall risk decreases slightly.
Rota remains in major danger.
Tinian and Saipan risk increase slightly compared with the more Rota-focused Update #14.
Intensity forecast is more complicated because of the partial eyewall replacement cycle.

What Changed From Update #14?
Track
Update #14 said Bavi was moving west and expected to turn WNW within 12–24 hours.
This update says Bavi has now moved west-northwest over the last 6 hours.
That means the expected turn appears to be happening.
JTWC also says some models shifted poleward, meaning farther north. Because of that, the official track was nudged slightly north while still keeping the center between Rota and Tinian.
This is better news for Guam than if Bavi had continued west or west-southwest.

Track Confidence
This changed.
Update #14 had high confidence in the track.
This update says medium confidence, because model spread increases later and some models are now showing different north/south solutions.
So while the near-term track is still fairly consistent, JTWC is acknowledging more uncertainty.

Steering Pattern
The deep-layer subtropical ridge to the north is now steering Bavi on a west-northwest path.
This is the turn we were watching for.
The key point:
The longer Bavi stayed west or WSW, the more concern for Guam and Rota.
Now that it has started WNW, the core risk shifts more toward Rota, Tinian, and possibly Saipan, rather than Guam.

Intensity / Eyewall Replacement
This update is more complex.
JTWC says a partial eyewall replacement cycle is occurring or trying to occur.
Two possible outcomes:
The outer band wraps around and collapses the inner eye.
The inner eye survives and the outer ring fades.
Either way, JTWC expects some weakening in the short term, especially over the next 12 hours.
After that, once the process finishes, Bavi may re-intensify again because the environment ahead is still extremely favorable.
Forecast peak:
Official JTWC peak: about 175 mph
Possible higher peak: 183 mph
HAFS-A extreme possibility: 190 mph
Even if the storm weakens temporarily, it remains an extremely dangerous super typhoon.

Size / Wind Field
This is very important.
JTWC says Bavi will gradually expand and become an extremely massive circulation.
Gale-force winds may extend up to 345 miles from the center later in the forecast period.
That means impacts will extend far from the center. A direct eyewall passage is not required for serious conditions.

Model Guidance
Important model trend:
HAFS-A, HWRF, and GFS shifted north.
AI models, ECMWF, GALWEM, and NAVGEM changed little.
JTWC nudged the official track slightly north.
The forecast still places the center between Rota and Tinian.
This means the overall track did not radically change, but the northward adjustment is meaningful.
Island Risk Assessment
Personal interpretation based on this JTWC update. Not official probabilities.

Guam
Direct eyewall risk: Low to Moderate
Estimated direct-hit chance: 6–12%
Overall impact risk: High
Trend from previous update: Slightly lower
Assessment: Guam’s direct eyewall risk decreases slightly because Bavi has started moving west-northwest and the track was nudged north. However, Guam is still close enough to experience strong tropical storm conditions, possible typhoon-force gusts, heavy rain, dangerous surf, and power issues.

Rota
Direct eyewall risk: Very High
Estimated direct-hit chance: 35–50%
Overall impact risk: Extreme
Trend from previous update: Still very high, but slightly less focused than Update #14
Assessment: Rota remains in a very dangerous position. The track is still between Rota and Tinian, so Rota remains one of the highest-risk islands. The slight northward adjustment may reduce the direct-hit odds a little compared with the previous “very close to Rota” wording, but the risk remains severe.

Tinian
Direct eyewall risk: Very High
Estimated direct-hit chance: 40–55%
Overall impact risk: Extreme
Trend from previous update: Increased slightly
Assessment: Tinian’s risk increases slightly because the forecast track nudged north while still passing between Rota and Tinian. Tinian is now arguably one of the main focus points for potential core impacts.
Saipan

Direct eyewall risk: Moderate to High
Estimated direct-hit chance: 25–40%
Overall impact risk: Very High to Extreme
Trend from previous update: Increased slightly
Assessment: Saipan’s direct eyewall risk increases slightly because of the poleward adjustment and the expected expansion of Bavi’s wind field. Even if the center passes south, Saipan could still experience dangerous conditions, especially if the storm grows larger during eyewall replacement.

Bottom Line
This update is somewhat better for Guam because the expected west-northwest turn has begun and the track was nudged slightly north. Guam is still not out of danger, but a direct eyewall passage is less likely than it was during the west or west-southwest motion.
The highest-risk corridor remains Rota to Tinian, with Saipan still at serious risk due to the slight northward adjustment and the storm’s expanding size.
The biggest new issue is the partial eyewall replacement cycle. It may cause short-term weakening, but it may also make Bavi larger. Once the cycle finishes, JTWC expects possible re-intensification before or near passage through the Marianas.

JTWC Warning #14 Analysis – Super Typhoon Bavi

Converted to mph / miles for easier reading

Summary
Bavi is about 405 miles east of Andersen AFB.
It tracked west over the past 6 hours at about 8 mph.
Significant wave height is now around 50 feet.
JTWC says the earlier west-southwest movement has ended.
Bavi is still expected to turn west-northwest within 12–24 hours.
The forecast track is very similar to the previous forecast, but the center is now forecast to pass very close to Rota.
An eyewall replacement cycle may be starting now or very soon.
Bavi may weaken slightly during the eyewall replacement, then strengthen again near the Marianas.
Peak forecast remains around 175 mph, with some model guidance showing up to 183 mph.
Track confidence is high. Intensity confidence is low for the next 3 days because of the eyewall replacement cycle.

Forecast Change Score: 6.5/10
This is a meaningful update, but not because of a huge track change.
The biggest changes are:
The WSW motion has ended.
The storm is back to westward movement.
The expected WNW turn is still forecast within 12–24 hours.
The track has stabilized after recent southward shifts.
The center is forecast to pass very close to Rota.
Eyewall replacement is likely beginning, which may make the storm larger.

What Changed From Warning #13?

Track
Warning #13 said the track leaned slightly south because of the earlier WSW motion.
Warning #14 now says the model group had shifted south over the past few cycles, but has stabilized.
That means JTWC is not showing another big southward jump right now.
However, the official forecast now specifically says:
The center will pass very close to Rota.
That is a serious increase in focus for Rota.

Motion
This is important:
#13: Bavi moved west-southwest
#14: Bavi moved west
That is slightly better for Guam than continued WSW motion, but it is still not the WNW turn yet.
The WNW turn is now expected within 12–24 hours.

Steering Pattern
JTWC says Bavi is being pushed west by a strong subtropical ridge to the north.
The WNW turn is expected when:
The near-equatorial ridge influence weakens.
A stronger ridge builds northeast of the storm.
Bavi accelerates out of the weak steering setup.
Simple version:
Right now: still west
Next 12–24 hours: expected WNW turn
After that: WNW motion should continue
For Guam/Rota, the key question remains:
Does Bavi turn WNW on time, or does it keep moving west longer?
If it turns WNW on schedule, Guam’s direct-eyewall risk stays lower. If it stays west longer, Guam and Rota risk goes up.

Intensity / Eyewall Replacement
This is the biggest meteorological change.
JTWC says an eyewall replacement cycle may begin imminently, if not already underway.
That can cause:
Temporary weakening during the first 24 hours.
A larger eye.
A broader wind field.
Stronger winds spreading farther from the center.
Possible re-intensification after the cycle finishes.
JTWC still expects Bavi to regain or maintain extreme strength near the Marianas, possibly around 175 mph, with higher intensity still possible.
This line is very important:
“The storm will grow very large in size… so impacts will occur far from the center.”
That means even islands not directly hit by the eye could still experience significant impacts.

Model Guidance
Models remain tightly grouped.
Track has stabilized after recent southward shifts.
JTWC track is close to the multi-model consensus.
Track confidence is high.
The official forecast takes the center very close to Rota.
Intensity guidance is mixed because of the eyewall replacement cycle.

Island Risk Assessment
Personal interpretation based on JTWC Warning #14 — not official JTWC probabilities.

🇬🇺**** Guam
Direct eyewall risk: Low to Moderate
Estimated direct-hit chance: ~10–18%
Overall impact risk: High
Trend from #13: ➡️ About the same / slightly better than if WSW continu**ed
Assessment: Guam is still not in the most likely eyewall path. The end of the WSW motion is somewhat better for Guam, but Bavi is still moving west and the WNW turn has not fully happened yet. Guam can still see strong tropical-storm conditions, possible typhoon conditions, heavy rain, dangerous surf, and power outages.

🇲🇵 Rota
Direct eyewall risk: Very High
Estimated direct-hit chance: ~45–60%
Overall impact risk: Extreme
Trend from #13: ⬆️** Higher
Assessment: Rota is now the island of greatest concern. JTWC specifically says the center is forecast to pass very close to Rota. This is a serious situation for Rota.

Tinian
Direct eyewall risk: High to Very High
Estimated direct-hit chance: ~30–45%
Overall impact risk: Extreme
Trend from #13: ➡️ Still very high
Assessment: Tinian remains in the high-risk corridor. If the track wobbles slightly north or the wind field expands, Tinian could still experience severe conditions.

🇲🇵 Saipan
Direct eyewall risk: Moderate to High
Estimated direct-hit chance: ~20–35%
Overall impact risk: Very High
Trend from #13: ➡️ to slightly lower for direct eyewall, but still serious
Assessment: Saipan is not the most favored direct-hit location in this update, but it remains close enough that a northward wobble or expanding wind field could bring dangerous conditions.

Bottom Line
Warning #14 does not show a major new track shift, but it does sharpen the focus: Rota is now the island with the highest direct-eyewall concern.
For Guam, the fact that Bavi moved from WSW back to west is slightly better news, but the storm has not started a confirmed WNW turn yet. Guam is still not the most likely direct-hit location, but it remains close enough that preparations should continue seriously.
The biggest new concern is the eyewall replacement cycle. If it starts now, Bavi may weaken slightly at first, but the storm may become larger, and JTWC warns that impacts will occur far from the center.

JTWC Warning #13 Analysis – Super Typhoon Bavi

Converted to mph / miles for easier reading

Summary
Bavi is about 455 miles east of Hagatna, Guam.
It tracked west-southwest over the past 6 hours at about 8 mph.

Maximum significant wave height is about 44 feet.
JTWC says the overall forecast philosophy is mostly unchanged from #12.

The storm is still forecast to turn west-northwest within the next 24 hours.

The low-level center is still forecast to pass between Rota and Tinian.

Peak intensity forecast is now around 168 mph, slightly lower than the prior 175 mph forecast.

Track confidence remains high.

JTWC is now leaning the track slightly southward to account for the minor southward shift/current motion.

Forecast Change Score: 5/10
This is a moderate update, but not a major forecast change.

The biggest items are:
Observed motion changed to west-southwest.
JTWC acknowledges a very minor southward shift.
Official track still passes between Rota and Tinian.
WNW turn is still forecast within 24 hours.
Peak intensity lowered slightly from about 175 mph to 168 mph.

What Changed From Warning #12?
Track
The partial #13 made it look concerning because Bavi moved west-southwest.
The full #13 confirms that JTWC noticed it, but they are not treating it as a major track change.

Important line:
“Forecast philosophy remains consistent with no significant deviations from the prior issuance.”
That means the WSW motion is being incorporated as a minor southward adjustment, not a full southward track shift toward Guam.

Closest Approach
Still focused on:
Rota ↔ Tinian
JTWC specifically says the low-level circulation center is forecast to pass between Rota and Tinian.
So even with the minor southward shift, the official forecast still does not show a direct Guam hit as the most likely scenario.

Steering Pattern
This update gives a clearer explanation of why Bavi slowed and moved WSW.

The ridge pattern is being disrupted by a longwave trough passing to the north. That weakens and splits the broad ridge, causing a weaker steering environment.

Simple version:
Bavi is in weak steering.
Weak steering allows slower motion and small wobbles.
The storm moved WSW over the past 6 hours.
After the next 24 hours, Bavi is still expected to turn west-northwest and accelerate out of the weak steering zone.

This is still the critical question:
Does Bavi turn WNW on schedule?
If yes: main risk stays Rota/Tinian, with Saipan still serious.

If delayed: risk rises for Rota and Guam.
If earlier/sharper: risk shifts more toward Tinian/Saipan.

Intensity
Peak intensity forecast came down slightly.
Previous #12 peak: about 175 mph
New #13 peak: about 168 mph
That is not a big comfort difference. It is still a very dangerous Category 5 super typhoon.

JTWC also says Bavi has likely reached or is near peak intensity, but it can maintain super typhoon strength through much of the forecast period.

Eyewall Replacement Cycle
ERC remains a major uncertainty.
If an eyewall replacement cycle starts:
Peak winds may fluctuate.
The eye may become larger.
The wind field can expand.
More islands can feel stronger winds even if the center misses them.
That matters especially for Saipan and Guam, because an expanded wind field can widen the area of serious impacts.

Model Guidance
Track guidance remains very strong.
Cross-track spread near closest approach: 111 km / about 69 miles
That is still tight.
JTWC track is near the multi-model consensus.
JTWC is leaning slightly southward to account for the minor southward shift.
So, model agreement remains good, but the official forecast nudged slightly toward the southern side.

Island Risk Assessment
Personal interpretation based on JTWC Warning #13 — not official JTWC probabilities.

🇬🇺**** Guam
Direct eyewall risk: Low to Moderate
Estimated direct-hit chance: ~10–18%
Overall impact risk: High
Trend from #12: ⬆️ Slightly higher
Assessment: Guam is still not in the most likely eyewall path, but the WSW motion and slight southward adjustment raise concern somewhat. If the WNW turn is delayed, Guam’s risk increases further.

🇲🇵 Rota
Direct eyewall risk: High
Estimated direct-hit chance: ~35–45%
Overall impact risk: Extreme
Trend from #12: ⬆️** Higher
Assessment: Rota’s risk increased. The forecast still passes between Rota and Tinian, but the southward lean brings the core closer to Rota.

Tinian
Direct eyewall risk: Very High
Estimated direct-hit chance: ~35–45%
Overall impact risk: Extreme
Trend from #12: ➡️ About the same
Assessment: Tinian remains in the main danger corridor. A small northward adjustment would put Tinian closer to the core; a small southward adjustment favors Rota.

🇲🇵 Saipan
Direct eyewall risk: Moderate to High
Estimated direct-hit chance: ~20–30%
Overall impact risk: Very High
Trend from #12: ⬇️ Slightly lower
Assessment: Saipan remains at serious risk, especially if the storm expands or shifts north. But this update keeps the main focus farther south, between Rota and Tinian.

Bottom Line
Warning #13 confirms the west-southwest motion, but JTWC is not calling this a major forecast change. The official track remains close to the previous forecast and still brings the center between Rota and Tinian, with a slight southward lean.

For Guam, this update is more concerning than #12, but still does not make a direct Guam hit the most likely outcome. For Rota, the risk has increased. Tinian remains in very high danger. Saipan remains at serious risk but is slightly less favored for a direct eyewall passage compared with earlier updates.

The next key thing to watch is simple:
If Bavi begins turning WNW within the next 24 hours, Guam’s direct-hit risk stays lower. If Bavi keeps moving west or WSW longer than expected, Guam and Rota’s risk will rise.

JTWC Warning #12 Analysis – Super Typhoon Bavi

Converted to mph / miles for easier reading

Summary
Bavi is about 501 miles east of WFO Guam.
It has continued moving west at about 11 mph.
Maximum significant wave height is about 42 feet.
Bavi is expected to keep moving mostly west for another 12–24 hours, then turn west-northwest.
Forecast peak intensity remains around 175 mph within the next 24–36 hours.
Bavi is expected to remain a super typhoon as it passes near the Mariana Islands.
Track confidence remains high, with only about 55 miles of cross-track spread near closest approach to Tinian and Rota.

Forecast Change Score: 4/10
This is not a major track change. It is more of a confirmation update, but there are a few useful details.
Biggest changes from #11:
Track: Mostly unchanged.
Motion: Still west, still slow.
WNW turn: Still expected after about 24 hours.
Track confidence: Still high, and model spread near closest approach is tight.
Intensity: Still forecast to peak around 175 mph, but JTWC now says the extreme intensification may “cool off” slightly while steering is weak.

What Changed From Warning #11?
Track
The track is still mainly the same. JTWC continues to focus the closest approach around the Tinian and Rota area.
The important line is:
Cross-track spread of 89 km / about 55 miles at closest point of approach to Tinian and Rota.
That means the models are still in very good agreement near the Marianas.

Steering Pattern
This update gives a more detailed explanation.
The subtropical ridge is still steering Bavi, but the passing trough to the north is causing a split in the broad ridge. That creates a weaker steering environment, which is why Bavi is slowing down.
Simple version:
Ridge still controls the storm.
Trough weakens/splits the ridge.
Storm slows down.
After about 24 hours, Bavi should turn west-northwest.
This is still the key question:

Does Bavi turn WNW on schedule, or does it stay west longer?

Turns WNW on schedule = highest risk stays around Rota/Tinian/Saipan
Stays west longer = risk increases for Rota/Guam
Turns WNW earlier = risk shifts more toward Tinian/Saipan

Intensity
Bavi is still expected to become extremely intense.
Forecast peak: 280 km/h / about 175 mph
Timing: within 24–36 hours
HAFS is still more aggressive, showing a possible peak above 295 km/h / about 183 mph
GFS is much weaker, around 195–220 km/h / 121–137 mph
JTWC is siding with the higher end because conditions remain favorable.

Eyewall Replacement / Dry Air / Shear
An eyewall replacement cycle remains possible around the time Bavi approaches the islands.
If that happens:
Peak winds may level off or fluctuate.
The wind field may expand.
More islands could feel stronger winds even if the eye does not pass directly overhead.
JTWC also mentions Bavi will push against a dry air mass to the northwest and wind shear will increase after about 3 days. Shear could reach about 28 mph by Day 4. That should eventually weaken the storm, but likely after the main threat to the Marianas.

Model Guidance
Model agreement remains strong.
Cross-track spread near closest approach: about 55 miles
JTWC track is near the multi-model consensus.
The official track leans slightly toward the southern side and toward experimental AI guidance.
Track confidence: High
Intensity confidence: Medium
That southern lean is worth noting because it keeps Rota at very high concern and keeps Guam from being completely out of the picture.

Island Risk Assessment
Personal interpretation based on JTWC Warning #12 — not official JTWC probabilities.

🇬🇺**** Guam
Direct eyewall risk: Low to Moderate
Estimated direct-hit chance: ~8–15%
Overall impact risk: High
Trend from #11: ➡️ About the same / slightly elevated
Assessment: Guam is still not in the most likely eyewall path, but Bavi is still moving west and the official forecast leans slightly south of consensus. If the WNW turn is delayed, Guam’s risk increases.

🇲🇵 Rota
Direct eyewall risk: Moderate to High
Estimated direct-hit chance: ~30–40%
Overall impact risk: Very High to Extreme
Trend from #11: ⬆️** Slightly higher
Assessment: Rota remains in a very dangerous position. The forecast discussion specifically references closest approach to Tinian and Rota, and the official track leans slightly southern.

Tinian
Direct eyewall risk: Very High
Estimated direct-hit chance: ~35–45%
Overall impact risk: Extreme
Trend from #11: ➡️ About the same
Assessment: Tinian remains one of the highest-risk islands. Current guidance still supports a close pass or possible eyewall impact.

🇲🇵 Saipan
Direct eyewall risk: High
Estimated direct-hit chance: ~25–35%
Overall impact risk: Very High to Extreme
Trend from #11: ➡️ to slightly lower
Assessment: Saipan remains at serious risk, especially if the track shifts north or if the wind field expands. But compared with Rota/Tinian, this update keeps the strongest focus a little farther south.

Bottom Line
Warning #12 does not show a major track change. Bavi is still moving west, still expected to turn west-northwest after about 24 hours, and still forecast to become an extremely dangerous super typhoon near 175 mph.
The highest-risk corridor remains focused around Rota and Tinian, with Saipan still at serious risk and Guam still lower risk for a direct eyewall passage but not out of the picture.

The main thing to watch today is simple:
If Bavi turns WNW on schedule, Guam’s direct-hit risk stays lower. If it keeps moving west longer than forecast, Guam and Rota’s risk goes up.

The forecasted typhoon track on Zoom Earth reflects the latest official update from the Joint Typhoon Warning Center (JTWC). Just sharing to people who are interested in following the storm’s progress.

GPT-5.5 Analysis (set to high intelligence)

JTWC Warning #11 Analysis – Typhoon Bavi

Converted to mph / miles for easier reading

Summary

Bavi is about 555 miles east of Andersen AFB.

It has continued moving west at about 12 mph.

Maximum significant wave height is about 40 feet.

Bavi underwent extreme rapid intensification, strengthening from about 70 mph to 145 mph in 24 hours.

Peak intensity is still forecast around 175 mph within about 24 hours.

Closest approach remains near the previous forecast, around 05/21:00 UTC, which is about Monday 7:00 AM Guam/CNMI time.

Track confidence remains high.

Forecast Change Score: 5/10

This is not a major track change, but it is a major confirmation that Bavi has rapidly intensified exactly as feared.

Biggest change from #10:
Track: Little changed.
Intensity: Much more serious now because ERI already happened.
Timing: Closest approach moved about 1 hour earlier compared with #10.
Turn timing: WNW turn now expected after 24 hours, instead of after 36 hours.

What Changed From Warning #10?
Track

The track is mostly the same. JTWC says the closest approach to Saipan and Rota remains similar to the previous forecast.

That means there is no new major southward or northward shift in this update.

Motion

Bavi is still moving west, but it has slowed slightly.
#10: about 13 mph
#11: about 12 mph

JTWC expects the forward speed to stay below about 12 mph for the next 36 hours.

West-Northwest Turn

This is important.

In #10, JTWC said the turn west-northwest would happen after about 36 hours.

In #11, they now say the turn west-northwest should happen after about 24 hours.

That slightly earlier WNW turn is a little better for Guam if it verifies, because a longer westward motion would increase risk for Guam/Rota. But the official track itself remains mostly unchanged.

Intensity

This is the biggest story.
Bavi strengthened from about 70 mph to 145 mph in 24 hours.
That is extreme rapid intensification.

JTWC still forecasts Bavi to reach around 175 mph within about 24 hours.

After that, increasing wind shear and a possible eyewall replacement cycle should limit further strengthening and eventually start weakening the storm.

Wind Shear / Eyewall Replacement

After about 36 hours, wind shear is expected to increase.
Around 60 hours: about 22 mph of shear

By 5 days: about 35–40 mph of shear
An eyewall replacement cycle remains likely. If that happens:

Peak winds may level off or weaken temporarily.
The wind field may expand.

More islands could experience stronger winds farther from the center.

That means even if the eye misses an island, impacts can still be serious.

Model Guidance

Model guidance remains tight.

Most guidance is still clustered together.

NAVGEM remains the main southern outlier, showing a track south of Rota.

The main guidance spread is about 63 miles at 60 hours, just after passage near the Marianas.

At 5 days, cross-track spread is about 86 miles, with along-track spread about 92 miles.

JTWC has high confidence throughout the forecast period, which is stronger wording than earlier updates.

Island Risk Assessment
Personal interpretation based on JTWC Warning #11 — not official JTWC probabilities.

🇬🇺** Guam
Direct eyewall risk: Low to Moderate
Estimated direct-hit chance: ~6–12%
Overall impact risk: High
Trend from #10: ➡️ to slightly lower
Assessment: Guam is still not in the most likely eyewall path. The slightly earlier expected WNW turn is somewhat better for Guam, but the risk is not zero. If Bavi stays west longer than forecast or shifts south again, Guam’s risk would increase.

🇲🇵** Rota
Direct eyewall risk: Moderate to High
Estimated direct-hit chance: ~25–35%
Overall impact risk: Very High
Trend from #10: ➡️ About the same
Assessment: Rota remains in a very dangerous position. The official track has not changed much, but Rota is close enough that a small southward shift or wobble could bring the core much closer.

🇲🇵** Tinian
Direct eyewall risk: Very High
Estimated direct-hit chance: ~35–45%
Overall impact risk: Extreme
Trend from #10: ➡️ About the same
Assessment: Tinian remains one of the highest-risk islands. The forecast corridor still supports a very close passage or potential eyewall impact.

🇲🇵** Saipan
Direct eyewall risk: High to Very High
Estimated direct-hit chance: ~30–40%
Overall impact risk: Extreme
Trend from #10: ➡️ About the same
Assessment: Saipan remains at serious risk. Even if the center passes south, an expanded wind field from an eyewall replacement cycle could still bring dangerous conditions.

Bottom Line
Warning #11 does not show a major track change. The forecast remains close to #10, with Bavi expected to pass near the Rota–Tinian–Saipan corridor.

The biggest change is that Bavi has now actually undergone extreme rapid intensification, strengthening to around 145 mph, with a forecast peak near 175 mph.

This confirms that the dangerous scenario is unfolding.

For Guam, direct-hit risk remains lower than the CNMI, and the earlier expected WNW turn is slightly better news. But Guam should still continue preparations because Bavi is now an extremely powerful typhoon with a potentially expanding wind field.

The forecasted typhoon track on Zoom Earth reflects the latest official update from the Joint Typhoon Warning Center (JTWC). Just sharing to people who are interested in following the storm’s progress.

GPT-5.5 Analysis (set to high intelligence)

JTWC Warning #10 Analysis – Typhoon Bavi

Summary
Bavi is about 627 miles east of Andersen AFB.

It has continued moving almost due west at about 13 mph.

Maximum significant wave height is about 39 feet.

The forecast track is little changed from Warning #9.
Closest approach to the Marianas is still expected around 05/22:00 UTC, which is about Monday 8:00 AM Guam/CNMI time.

Bavi is still forecast to rapidly intensify to around 175 mph.

After about 36 hours, increasing wind shear and a possible eyewall replacement cycle may limit further strengthening and cause gradual weakening.

Track confidence remains high for the next 3 days.
What Changed From Warning #9?

Main change: Not much. This is more of a confirmation update than a major shift.

Track: Mostly unchanged.

Intensity: Still forecast to peak near 175 mph.

Steering: Still controlled by the subtropical ridge.

Timing: Closest approach remains around Monday
morning.

Model spread: Still fairly tight, except NAVGEM remains a southern outlier.

Track / Steering Pattern
Bavi is still moving almost due west because of the subtropical ridge to the northwest/north.

The important part:
For the next 36 hours, the storm should keep a mainly westward movement.

After 36 hours, it is still forecast to turn west-northwest.

That means the key question remains:
How long does Bavi keep moving west before turning west-northwest?

Longer west movement = more risk for Rota/Guam

Earlier west-northwest turn = more risk for Tinian/Saipan

Right now, JTWC says there is little deviation from the previous forecast track, so this update does not show another major southward shift.

Intensity / Wind Shear
Rapid intensification is expected to continue for about 36 more hours.

Peak intensity forecast remains around 175 mph.
Wind shear is expected to increase to around 22 mph by 60 hours.

By 5 days, wind shear may increase to around 35–40 mph.

That shear, combined with a possible eyewall replacement cycle, should eventually limit strengthening and cause gradual weakening.

Model Guidance
Most models remain in a fairly tight group.
NAVGEM is the main southern outlier and suggests a track south of Rota.

The rest of the guidance has a spread of about 69 miles at 3 days and 86 miles at 5 days.
JTWC remains close to the multi-model consensus.
Track confidence is high through 3 days and medium after that.

Island Risk Assessment
Personal interpretation based on JTWC Warning #10 — not official JTWC probabilities.

🇬🇺** Guam
Direct eyewall risk: Low to Moderate
Estimated direct-hit chance: ~8–15%
Overall impact risk: High
Trend from #9: ➡️ About the same / maybe slightly better
Assessment: Guam is still not in the most likely eyewall path, but risk is not zero. A longer westward motion or a southward model shift would increase Guam’s risk. Even without a direct hit, Guam can still see strong winds, heavy rain, dangerous surf, and possible power outages.

🇲🇵** Rota
Direct eyewall risk: Moderate to High
Estimated direct-hit chance: ~25–35%
Overall impact risk: Very High
Trend from #9: ➡️ About the same
Assessment: Rota remains in a dangerous position. The official track is not dramatically farther south, but Rota is close enough that a small shift could bring much worse conditions.

🇲🇵** Tinian
Direct eyewall risk: Very High
Estimated direct-hit chance: ~35–45%
Overall impact risk: Extreme
Trend from #9: ➡️ About the same
Assessment: Tinian remains one of the highest-risk islands. The forecast corridor still supports a very close pass or possible eyewall impact.

🇲🇵** Saipan
Direct eyewall risk: High to Very High
Estimated direct-hit chance: ~30–40%
Overall impact risk: Extreme
Trend from #9: ➡️ About the same
Assessment: Saipan remains at serious risk. Even if the center passes south, the wind field may expand due to an eyewall replacement cycle, meaning dangerous conditions can still reach Saipan.

Bottom Line
Warning #10 does not show a major new shift. It confirms the dangerous scenario from Warning #9: Bavi is still moving west, still forecast to become an extremely intense typhoon near 175 mph, and still expected to pass near the Rota–Tinian–Saipan corridor.

For Guam, the direct-hit risk remains lower than the CNMI, but it is not zero. For Rota, Tinian, and Saipan, this remains a serious and potentially dangerous situation.
The next thing to watch is whether Bavi continues west longer than expected or starts turning west-northwest on schedule.

The forecasted typhoon track on Zoom Earth reflects the latest official update from the Joint Typhoon Warning Center (JTWC). Just sharing to people who are interested in following the storm’s progress.

GPT-5.5 Analysis:

JTWC Warning #9 Analysis – Super Typhoon Bavi

Summary

Bavi has now entered Extreme Rapid Intensification (ERI).

JTWC forecasts the storm to strengthen to at least 280 km/h (150 kt) within the next 2 days.

The storm is now moving due west as the subtropical ridge to the north becomes the primary steering mechanism.

A trough passing north of Japan will weaken the steering currents and slow the storm, but it is still not expected to recurve northward.

The official forecast track has shifted about 56 km farther south, with the center now forecast to pass between Rota and Tinian.

Track confidence remains high, while intensity confidence decreases after 3 days due to uncertainty with the timing of the eyewall replacement cycle (ERC).

What’s Changed Since Warning #8?

📍 Track shifted ~56 km south.
📍 Forecast now passes between Rota and Tinian instead of just south of Tinian.
🌪️ Peak forecast intensity increased from** 250 km/h (135 kt**) to** 280 km/h (150 kt**).
🚀 Bavi has officially entered **Extreme Rapid Intensification (**ERI).
🌬️ Increasing easterly wind shear is expected after about 3 days, which should gradually weaken the storm after its peak.

Model Guidance

Most forecast models remain tightly clustered, with the main guidance contained within a 46 km envelope.
JTWC notes that NAVGEM and one ECMWF-based solution are southern outliers that bring the center over or just north of Guam, while most guidance still favors a track between Rota and Tinian.

Bottom Line

This is one of the most significant updates so far. The forecast has shifted slightly south, increasing concern for Rota and Guam, while the highest risk remains focused between Rota and Tinian. The steering pattern has remained remarkably consistent over the past several JTWC updates, giving forecasters high confidence in the overall track. However, Bavi is now undergoing Extreme Rapid Intensification and is expected to become a very dangerous super typhoon before reaching the Northern Mariana Islands.

As always, everyone in Guam, Rota, Tinian, and Saipan should continue monitoring official forecasts and complete preparations as soon as possible. Even if the eye does not pass directly overhead, a storm of this size and intensity can produce dangerous conditions well away from the center.

Edit 1:

Island Risk Assessment (Based on JTWC Warning #9)
(Personal interpretation based on the latest JTWC forecast. These are not official JTWC probabilities*.)*

🇬**🇺****** Guam
Direct eyewall risk: Low to Moderate (10–18%)
Overall impact risk: High
Assessment: A direct hit is still not the most likely outcome, but the southward shift increases Guam’s risk. Even without a direct hit, tropical storm to typhoon conditions, dangerous surf, heavy rain, and power outages remain possible.

🇲🇵 Rota
Direct eyewall risk: Moderate to High (20–30%)
Overall impact risk: Very High
Assessment: Rota’s risk has increased with the latest southward shift. If the track shifts slightly farther south, Rota could experience the eyewall or the strongest part of the storm.

🇲🇵 **Tinian
Direct eyewall risk: Very High (40–50%)
Overall impact risk: Extreme
Assessment: Tinian remains in the highest-risk corridor. Current guidance places the forecast track between Rota and Tinian, making Tinian one of the islands most likely to experience the core of the typhoon.

🇲🇵 Saipan
Direct eyewall risk: Very High (30–40%)
Overall impact risk: Extreme
Assessment: Although the latest forecast shifted slightly south, Saipan remains at very high risk. A small northward wobble could still bring the eyewall directly over the island, and significant impacts are likely even if the center passes south.

The highest current risk remains focused on the Rota–Tinian–Saipan corridor. Guam is still outside the most likely eyewall path, but the latest southward shift means it should continue full preparations. With Bavi expected to become an extremely intense super typhoon, all populated Mariana Islands should be prepared for dangerous conditions regardless of the exact track.

The forecasted typhoon track on Zoom Earth reflects the latest official update from the Joint Typhoon Warning Center (JTWC). Just sharing to people who are interested in following the storm’s progress.

ChatGPT analysis: (warning wall of text)

JTWC Warning #8 – Super Typhoon Bavi (09W) Update
Summary

Rapid intensification (RI) is now officially underway. Bavi has become well-organized (axisymmetric) and entered an environment highly favorable for strengthening.

JTWC forecasts at least 140 km/h (75 kt) of additional strengthening over the next 48 hours.
There is nearly a 100% chance of significant to extreme rapid intensification (RI/ERI) during the next two days.
Some high-resolution models continue to indicate a possible peak intensity of 285–295 km/h (155–160 kt) before an eyewall replacement cycle (ERC) begins.

The subtropical ridge remains the dominant steering mechanism, keeping Bavi on a west to west-northwest track toward the Northern Mariana Islands.
A trough moving east of Japan will temporarily slow the storm but is not expected to turn it northward.
Track confidence remains high, with the majority of forecast models tightly clustered just south of Tinian.

Changes Compared to Previous Updates
Track

Warning #6: Closest approach forecast just south of Tinian.
Warning #7: Slight northward adjustment toward Saipan.
Warning #8: Consensus shifted slightly back south, with the main model cluster again centered just south of Tinian.

Overall, the forecast has remained within a relatively narrow corridor despite these small adjustments.

Steering Pattern
No significant changes.
JTWC continues to forecast:
A strengthening subtropical ridge steering Bavi westward.
A temporary weakness caused by a trough north of Japan.
The trough slows the storm but does not cause it to recurve north.
This steering forecast has remained consistent since Warning #4.

Intensity
This is the biggest change.
Earlier warnings expected rapid intensification.
Warning #8 confirms that rapid intensification has now begun, with near-certain confidence that Bavi will continue strengthening dramatically over the next two days.

Island Risk Assessment
(My interpretation based on JTWC guidance — not official JTWC probabilities.)

Approximate Direct-Hit Likelihood (My Assessment)
Tinian: 40–50%
Saipan: 30–40%
Rota: 15–25%
Guam: 5–12%

Bottom Line

The overall forecast has become more confident rather than dramatically different.

The steering pattern remains stable.

Rapid intensification has officially begun.
Track confidence is high, with the strongest consensus continuing to favor the Tinian–Saipan corridor.

The highest risk remains for Tinian and Saipan, while Rota remains at meaningful risk if the track shifts south.
Guam is still outside the most likely eyewall path, but residents should continue preparations because even without a direct hit, a super typhoon can produce damaging winds, dangerous surf, heavy rain, and power outages well away from the center.

The forecasted typhoon track on Zoom Earth reflects the latest official update from the Joint Typhoon Warning Center (JTWC). Just sharing to people who are interested in following the storm’s progress.

ChatGPT analysis: (warning wall of text)

Thanks for sharing JTWC Warning #7. This is another important update, and overall I’d say the forecast has become even more stable. Here’s what changed compared with Warning #6.

1. The forecast track nudged slightly north
This is the biggest change I noticed.
Warning #6:
Closest approach just south of Tinian
Warning #7:
Closest approach to Saipan
That indicates a small northward adjustment in the forecast.
It’s not a dramatic shift, but it’s enough that the closest approach is now referenced to Saipan instead of south of Tinian.
This is slightly favorable for Guam, because the forecast moved a little farther away.

2. Model agreement improved again
This is actually the most encouraging part from a forecasting standpoint.
Previously:
Cross-track spread ≈ 259 km at 3 days
Now:
93 km at 3 days
That’s a major reduction.
It means the models are converging on a very similar track.
JTWC also says:
“Overall, the guidance agrees on the west-northwestward track without much further spread…”
That’s stronger language than in previous warnings.

3. The steering pattern hasn’t changed
This is exactly what we’ve been discussing for the last day.
JTWC is still saying:
Ridge near Kyushu builds.
Storm turns west.
Trough weakens the steering currents.
Storm slows.
Then resumes west-northwest.
So the large-scale steering pattern remains very consistent.

4. Rapid Intensification
No real changes here.
Still expected:
Another ~12 hours of gradual strengthening.
Then about 60 hours of RI.
That tells me JTWC still expects the storm to become extremely dangerous before reaching the Marianas.

5. Eyewall Replacement Cycle
Timing changed slightly.
Previous:
Around 72–84 hours.
Now:
48–60 hours.
That means the ERC may begin a little earlier.
This could mean:
Peak winds level off sooner.
Wind field may expand before reaching the islands.
That’s important because a larger wind field can affect a broader area even if peak winds stop increasing.

My updated assessment
Compared with Warning #6:
Guam
Risk has decreased slightly.
Not because the storm is weaker—it isn’t.
But because:
Track shifted slightly north.
Model agreement improved.
JTWC confidence remains high.

Saipan
My concern has increased slightly.
The forecast center is now referenced to Saipan rather than south of Tinian.

Tinian
Still at extremely high risk.
Remember:
A difference of 30–50 km between Saipan and Tinian is tiny for a super typhoon.
Both islands remain in the danger zone.

Rota
About the same.
Still depends on whether any later forecast shifts south again.

Biggest takeaway
What stands out to me isn’t just the slight shift toward Saipan—it’s that the forecast is becoming more consistent.

Over the last four warnings:
The steering pattern has remained essentially unchanged.
The expected rapid intensification has remained consistent.

The model spread has narrowed significantly.
JTWC continues to express high confidence in the track.
That’s generally a sign that forecasters have increasing confidence in where the storm is likely to go.

For you in Guam

If I compare your situation now to when you first shared Warning #4:
I’m more confident that Guam is not in the most likely eyewall path.

I would still complete preparations.

I would not relax just because of this one northward adjustment. Super typhoons can have damaging conditions extending well away from the eye, and a shift of even 50–100 km in later forecasts could still change the impacts on Guam.

At this point, if Warning #8 also keeps the track near Saipan with similarly tight model agreement, my confidence that the greatest risk remains focused on the northern CNMI would increase further.