2025 Global Model Runs Discussion (Out thru day 16)

[TomballEd]

Even the GFS ensembles have more Pacific systems. Much too early to get concerned but Euro just N of Caribbean threat in 2 weeks seems more likely.

May have two MDR systems in next two weeks.

[DunedinDave]

6z GFS with another "Perrycane". Big Bend cannot catch a break if this verifies. (no other operational model has it, so it's probably phantom, even a week out, it's already shifted back in time from Monday runs that were showing the gulf which are a telltale sign of phantom CAG.)

https://i.postimg.cc/fyykFrmZ/gfs-mslp-wind-seus-fh174-336.gif

As I said in another post, it’s almost the exact same track on almost the exact same day that Helene hit last year.

That said, I’m not buying it yet. GFS has Brownsville at 0z and Perry at 6z. It’s all over the place. No other models really showing much at least in the next week. I think if something forms it’s more likely to head into Mexico or the Yucatán and cross into the Pacific.

[Teban54]

0z ECMWF and 6z GFS both have a second MDR hurricane behind the 0/30 AOI, from a wave that emerges from Africa around Sep 20. Gets much closer to the islands, although obviously too early to be a serious concern especially for CONUS.

[Stratton23]

CMC caved to the GFS with a CAG system lifting due north out of the SW caribbean so wont be surprised when a lemon is issued for the NW caribbean in a couple of days, both models are also showing 3-4 areas to watch behind the CAG system, to no surprise modes are starting to see the effects of that MJO passage in a week

[LAF92]

CMC caved to the GFS with a CAG system lifting due north out of the SW caribbean so wont be surprised when a lemon is issued for the NW caribbean in a couple of days, both models are also showing 3-4 areas to watch behind the CAG system, to no surprise modes are starting to see the effects of that MJO passage in a week

The 12zGFS looks like it keeps that particular CAG festering in the BOC for a week then slings it the central Gulf towards the end of the run.

[MetroMike]

CMC caved to the GFS with a CAG system lifting due north out of the SW caribbean so wont be surprised when a lemon is issued for the NW caribbean in a couple of days, both models are also showing 3-4 areas to watch behind the CAG system, to no surprise modes are starting to see the effects of that MJO passage in a week

The 12Z CMC is a weak signal at the very end of the run.Would disregard it atm. Very weak sauce
and could be another spurious low that come and go this season.

[Stratton23]

MetroMike I respectfully disagree about disregarding it, its the first global model other than the GFS to indicate some sort of development in that region, GEPS does have some support for it , so while its a low chance, its definitely enough to watch, late september anyways is usually when the CAG starts becoming the main area to watch for development, so climatology is also a factor here

[TomballEd]

The op GFS has a most unlikely path to get a hurricane to Louisiana in 2 weeks.


Canadian has improved quite a bit since the 'crazy uncle' days but it isn't the premiere tropical model.

Right out about two weeks, Euro ensembles start seeing BoC systems which EPS 500 mb heights suggest would drift NE towards the Central/Eastern Gulf. This could be the big Florida hurricane that seems like an annual occurrence late September and October.

[BobHarlem]

18z GFS is back to another big bend weakish "perrycane", only the cmc shows anything possibly developing there on the other models. (Icon doesn't go out that far yet)

[Stratton23]

I will say one reason i dont think the GFS cant be discounted here is because it has consistently from run to run been moving development up in time with this CAG system, a few days ago it was forming this in the 216-240 hour range , this 18z run now by 120 hours has a weak TD existing in the NW, guess we will soon see if anything exists in the area the GFS develops in

[LarryWx]

Like they’ve been showing almost every day for over a week and although they don’t get to above the active avg ACE like they showed 2 weeks ago, the Euro Weeklies still end the below avg ACE starting with the week that begins Sept 22nd. It rises to near the 20 year active avg then and that lasts for the 3 weeks going through Oct 12th. It still has the most active week of the next 4 to be 9/22-28 (with ~13.5 ACE) and the 2nd most active being 9/29-10/5. It’s projecting ~40 ACE 9/15-10/12. That would bring total ACE up to ~80. That would keep season to date ACE well below the active era’s avg of ~103 as of then.

[LarryWx]

This 0Z UKMET post actually does belong here. For the first time, the UK has a TC (actually a TS) behind the current lemon in the far E MDR moving WNW:

NEW TROPICAL CYCLONE FORECAST TO DEVELOP AFTER 108 HOURS
FORECAST POSITION AT T+108 : 11.9N 16.7W

LEAD CENTRAL MAXIMUM WIND
VERIFYING TIME TIME POSITION PRESSURE (MB) SPEED (KNOTS)
-------------- ---- -------- ------------- -------------
1200UTC 16.09.2025 108 11.9N 16.7W 1008 35
0000UTC 17.09.2025 120 13.3N 19.7W 1008 29
1200UTC 17.09.2025 132 14.7N 23.2W 1008 28
0000UTC 18.09.2025 144 15.8N 26.7W 1009 32
1200UTC 18.09.2025 156 16.6N 29.8W 1010 27
0000UTC 19.09.2025 168 17.4N 31.9W 1010 27

[BobHarlem]

0z euro has a new wave collection after the current highlighted area


The wave near the islands winds up in the west Caribbean