u/BostonSucksatHockey

Wednesday will be a mostly sunny day after a few early morning clouds along the coast.

High temperatures will reach the mid to high 80s, with winds remaining mostly calm besides SW winds along the coast in the afternoon up to 10 mph.

https://www.weather.gov/okx/weatherstory

Some additional information - in case you're new to this sub (or just modeling in general)...

The Global Forecasting System (operated under the NOAA/NWS umbrella, i.e., "GFS" or the "American Model") is one of several global (i.e., synoptic) scale models used to aid official forecasts. Other models include the European model ("ECMWF"), the Canadian Model ("GEM" or "CMC"), and German Model ("ICON"), etc.

These are examples of synoptic scale models, which focus on large-scale atmospheric patterns. To put it simply, computers take the latest observational data and run them through complex algorithms that mock the laws of physics to determine plausible outcomes.

There also AI-based and AI-assisted models, which compare the latest observations with past observations over many years, to identify meteorological trends. For example, Google has developed its own AI-based line of models (e.g., "WeatherNext"). AI-assisted models use a blend of physics and historical trends.

The GFS model is particularly quirky and known to enter feedback loops in the long-term, resulting in a strong bias to produce monster low pressure systems. You'll see this in long-term modeling in the tropics during summer and also in the mid-latitudes during winter. It's one of the reasons this sub has strict posting requirements when it comes to posting modeling beyond 120 hours (5 days).

So why am I posting this?

• First, even a broken clock is right once in awhile. Last year, the GFS model was the first synoptic model to identify the disturbance that would become Hurricane Melissa.
• The 06z runs are not "one-offs." This is now a trend with several recent runs of GFS-based models producing at least a tropical depression in the MDR.
• The open question of the Madden-Julian Oscillation ("MJO"). This is a global scale weather pattern that can be highly influential on tropical development around the world.
  • When the MJO is in Phases 7, 8 and 1, conditions in the Atlantic become more favorable for tropical development. If the MJO is in any other phase, or is weak/neutral, then conditions will likely remain unfavorable.
  • GFS and ECMWF modeling of the MJO over the next 15 days are very different right now. (See Slide 9). The GFS has been trending toward an active MJO in Phase 7, albeit not until September.... but that could be linked to how its modeling in the Atlantic.
  • Notably, the latest GFS ensemble modeling of the MJO looks more like the ECWMF and other models, taking the MJO into a weak or neutral phase.

 ZCZC MIATWOEP ALL
 TTAA00 KNHC DDHHMM

 Tropical Weather Outlook
 NWS National Hurricane Center Miami FL
 500 AM PDT Tue Aug 18 2026

 For the eastern and central North Pacific east of 180 longitude:

 Active Systems:
 The National Hurricane Center is issuing advisories on Hurricane
 Lala, located a couple hundred miles south-southwest of French
 Frigate Shoals, Hawaii.

 1. South of Mexico:
 An area of low pressure is forecast to form several hundred miles 
 south of the coast of southern Mexico around the end of the week. 
 Gradual development of this system is likely thereafter, and a 
 tropical depression is expected to form this weekend while the 
 system moves west-northwestward, remaining well offshore of Mexico.
  * Formation chance through 48 hours...low...near 0 percent.
  * Formation chance through 7 days...high...80 percent.

 2. Western Portion of the East Pacific:
 A tropical wave located well to the west-southwest of the southern 
 tip of the Baja California Peninsula is producing disorganized 
 showers and thunderstorms. Environmental conditions appear conducive 
 for gradual development of this system, and a tropical depression 
 could form towards the end of the week or over the weekend while the 
 system moves generally westward across the western portion of the 
 east Pacific and into the central Pacific.
  * Formation chance through 48 hours...low...20 percent.
  * Formation chance through 7 days...medium...60 percent.


Forecaster Kelly/Pierce

Tuesday will be mostly sunny with dry conditions. Highs will be in the low to mid 80s under light NW winds.

https://www.weather.gov/okx/weatherstory

Monday will be mostly cloudy with highs in the upper 70s to mid 80s.

A chance of showers & thunderstorms in the morning and again in the evening.
A dry period is possible midday into the afternoon.

https://www.weather.gov/okx/weatherstory

The HREF ensemble solution suggests the bulk of rain falling between 8pm tonight and 8am Monday, but some individual deterministic model solutions suggest scattered showers could begin as early as 3 or 4pm and linger through mid-day or even afternoon on Monday.

Sunday starts as a seasonable day with partly cloudy skies and high temperatures reaching the lower 80s.

By Sunday evening, showers and possibly a few thunderstorms are forecasted through Monday morning.

https://www.weather.gov/okx/weatherstory

Hurricane Lala Tropical Cyclone Update
NWS Central Pacific Hurricane Center Honolulu HI   CP012026
Issued by NWS National Hurricane Center Miami FL
400 PM HST Sat Aug 15 2026
 
...HEAVY RAIN CONTINUES TO SPREAD ACROSS THE EASTERN MAIN HAWAIIAN ISLANDS... 

...400 PM HST (0200 UTC) POSITION UPDATE...

Radar data indicate that the eyewall of Lala is nearing South Point,  Hawaii.

An observation near South Point around 550 feet elevation recently reported 
a sustained wind of 51 mph (82 km/h) and a gust of 71 mph (114 km/h). 

An observation site at South Point Park also reported a sustained wind of 
49 mph (79 km/h) and a gust of 73 mph (117 km/h).

Peak rainfall measurements over the last 12 hours are between 12 to 13 
inches across windward Maui and the Big Island.   

SUMMARY OF 400 PM HST...0200 UTC...INFORMATION
----------------------------------------------
LOCATION...18.6N 155.9W
ABOUT 35 MI...55 KM S OF SOUTH POINT HAWAII
ABOUT 200 MI...320 KM SE OF HONOLULU HAWAII
MAXIMUM SUSTAINED WINDS...75 MPH...120 KM/H
PRESENT MOVEMENT...NW OR 320 DEGREES AT 9 MPH...15 KM/H
MINIMUM CENTRAL PRESSURE...988 MB...29.18 INCHES
 
$$
Forecaster Zelinsky/Evans