r/guam

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.

So we have a couple of Youtube mainlanders in the Marianas here for their YouTube clicks.

What do you guys think?

Sure you can visit the island and support the local economy but then why endanger yourself and place rescue personnel in the difficult position of possibly having to rescue your pale ass while filming Super Typhoon Bavi?

He also mispronounces Saipan “Sai Pay” 😂😂😂

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.

#TyphoonBavi

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.

These guys are ripping out in Tumon Bay!