2025 Global Model Runs Discussion (Out thru day 16)

[Teban54]

For clarity, this is what 12z CMC showed (as discussed above), near the end of the run.

[SFLcane]

ECMWF weeklies suggesting things are about to kick into overdrive in our backyard which ultimately leads to impacts for someone.

[LarryWx]

The CMC is showing a Gulf/CAG system.

Larry Cosgrove thinks there may be 2 or 3 storms from the CAG, and it is possible one of them develops in the Gulf or crosses Tehuantepec into the Gulf. Florida has been unlucky with late season storms.

https://groups.google.com/g/weatheramerica/c/aauyOY32C94

Current GOMEX feature on the tail end of the trough almost certainly will not develop, it is in a desert.
https://i.imgur.com/0BOlYx4.gif

Hey Ed,
Yeah, the current central Gulf feature may not develop. However, fwiw, the 0Z UKMET (a model that tends to be a bit more stingy with TCG than the GFS) is the 2nd run in a row that develops a TC from it after it moves S into the Bay of Campeche. This run actually has minimal TS winds early on. Whereas the prior run then moved it into a threatening position in the W-C Gulf, this run only moves it slowly back N to the end of the run:

NEW TROPICAL CYCLONE FORECAST TO DEVELOP AFTER 108 HOURS
FORECAST POSITION AT T+108 : 19.9N 94.7W

LEAD CENTRAL MAXIMUM WIND
VERIFYING TIME TIME POSITION PRESSURE (MB) SPEED (KNOTS)
-------------- ---- -------- ------------- -------------
1200UTC 03.10.2025 108 19.9N 94.7W 1009 36
0000UTC 04.10.2025 120 19.7N 93.9W 1008 31
1200UTC 04.10.2025 132 19.5N 93.9W 1006 31
0000UTC 05.10.2025 144 20.1N 94.2W 1005 29
1200UTC 05.10.2025 156 20.2N 94.0W 1005 26
0000UTC 06.10.2025 168 20.7N 94.5W 1004 27

[LarryWx]

A notable number of 6Z EPS members at 144 (~1/3) have a surface low in the Gulf (mainly northern) from something.

[kevin]

Another MDR MH on the 06z GFS. Because October is the new September.
The tropical wave which forms into this already leaves Africa in 3 - 4 days and a TD forms around +180hr in this run.

[Stratton23]

12z ICON has something brewing in the southern gulf

[Stormlover70]

12z ICON has something brewing in the southern gulf

image?

[cycloneye]

12z GFS has a MDR wave developing.

[Weathertracker96]

The 12z CMC is showing Gulf & Bahamas activity.

[Stratton23]

CMC/ GFS also show activity in the southern and western gulf

[cycloneye]

12z GFS has a MDR wave developing.

https://i.imgur.com/cwiZnTc.gif

Moves thru the northern Leewards and then recurves.

[LarryWx]

CMC/ GFS also show activity in the southern and western gulf

So, that makes Icon, GFS, and CMC as having Gulf tropical activity. So, the Gulf looks somewhat active (more active than most of the season so far in the day 8 or earlier output). However, the UKMET, which goes out only 168, did drop the Gulf TC per its textual output that it had on its prior 2 runs.

[Teban54]

Summaries of the potential systems (especially as there's a lot of confusion due to overlapping areas).

1. Low currently in the Gulf (potential in 3-7 days)

• There's currently a naked swirl in the western Gulf, largely devoid of convection. Surrounding environment is very dry.
• 12z ICON gets this south to the BoC where it develops. The last frame, in 7.5 days, moves it west towards Mexico as a 988 mb TS/H.
• All other models have the vorticity buried in Mexico.

2. Tropical wave currently in the Central Atlantic & Front that picks up Humberto and Imelda (potential in 5-10 days)

• There's an MDR wave at 45W firing convection.
• 12z CMC gets this to north of Greater Antilles, where it develops and heads west. It might also have merged with the tail of the front. The last frame, in 10 days, has it approaching SE Florida as a 1006 mb TS.
• 12z GFS appears to turn the tail end of the front into a TC in the NE Gulf by itself, which quickly landfalls in NOLA as a 1004 mb TS in 6 days
• No other models develop this, and have the wave killed off by the recurving Humberto and Imelda.

3. Tropical wave that leaves Africa around October 3 (potential in 8+ days)

• 12z GFS starts developing this wave once it reaches 45-50W, in ~9 days. It hits the northernmost LA islands as a hurricane, then recurves east of Bermuda with a peak of 948 mb.
• 12z ICON's last frame, in 7.5 days, shows a 1012 mb low at ~35W. It may have kept organizing had the run continued.
• 12z ECMWF-Fast's last frame, in 10 days, shows a weak vort near the Lesser Antilles. (I don't have the full Euro run yet.)

4. Possible CAG development in the Gulf (potential in 8+ days)

• 12z CMC appears to show a CAG that spans both sides of Central America. The Western Caribbean side appears to become dominant in 7 days, then attempt to tighten in the Gulf. The last frame, in 10 days, shows a lopsided 994 mb TS offshore the TX/Mexico border.
• 12z GFS shows a somewhat similar evolution, but delayed in time. Organization on the Atlantic side is most notable in ~9 days over the Yucatan Peninsula. The system then gets into BoC, peaks at 985 mb, and landfalls in Mexico in 12 days.
• ECMWF hasn't shown any CAG action around this time in recent runs.

It's important to note that "Gulf development" can refer to either #1, #4 or even #2, and "MDR development" can refer to either #2 or #3.

[Stratton23]

Well tonights model runs are very interesting so far lol , CMC has a TS in the gulf moving toward central- northern mexico, GFS buries it into BOC, but has another low riding wave developing in the caribbean, not seeing any troughs on the models for october, lots of ridging, not a typical upper air pattern for october

[ConvergenceZone]

Well tonights model runs are very interesting so far lol , CMC has a TS in the gulf moving toward central- northern mexico, GFS buries it into BOC, but has another low riding wave developing in the caribbean, not seeing any troughs on the models for october, lots of ridging, not a typical upper air pattern for october

Yea I was looking at that as well. It's really looking like this year is the year that the USA mainland escapes any tropical disasters.

[Stratton23]

ConvergenceZone eh i still wouldn’t say that just yet , that ridging pattern could definitely change and parts of the gulf ( mainly eastern gulf) could still be threatened down the road should a system develop and get into the gulf

[TomballEd]

6Z Euro tries to get something going in the Gulf but it is in a desert of dry air. Forgive use of snipping tool, normally I use a mouse to copy the image from the site but I don't have a keyboard or mouse and the little laptop's mousepad doesn't seen to know what a right click is. I don't have the big monitor either.

[LAF92]

FWIW The last couple GFS ensemble runs are fairly active in the southern gulf with activity migrating north between days 7-10

[REDHurricane]

Well tonights model runs are very interesting so far lol , CMC has a TS in the gulf moving toward central- northern mexico, GFS buries it into BOC, but has another low riding wave developing in the caribbean, not seeing any troughs on the models for october, lots of ridging, not a typical upper air pattern for october

Yea I was looking at that as well. It's really looking like this year is the year that the USA mainland escapes any tropical disasters.

This is the kind of comment that is destined to age like milk lol

[SFLcane]

Certainly a prediction to be taken with caution as this is the CFS but it fits with the favorable upper motion moving in mid month in Oct.