2025 Global Model Runs Discussion (Out thru day 16)

[BobHarlem]

With the caveat that 360 hr model runs are not to be taken literally... The (supposedly conservative) 0z ECMWF has two CV storms at the end of the run.

https://i.postimg.cc/R07DVDKB/ecmwf-mslp-pcpn-atl-84.png

The atmosphere around that west wave on the euro leans toward recurve if it develops. Really long range though.

[cajungal]

I think the long trackers will recurve before getting to the states esp as we are heading towards September. We have to look closer to the Caribbean and the Gulf I think this year if anything was to form.

[emeraldislenc]

Never know about the long trackers we have had many hurricanes in the past that formed in early to mid Sept that came across the Atlantic I think of Hugo and I think Fran just to name a few. Too early to say Cape Verde is closed!

[cajungal]

Never know about the long trackers we have had many hurricanes in the past that formed in early to mid Sept that came across the Atlantic I think of Hugo and I think Fran just to name a few. Too early to say Cape Verde is closed!

Yes but just different pattern. We would need to get a strong Bermuda ridge in place

[LarryWx]

Just like yesterday’s 12Z and today’s 0Z, the 6Z Euro has the low come off Africa Fri evening (not that far out…that’s why I think it’s worth posts). It becomes a TD Saturday night near the CVs, moves slightly S of due W from there, and ends up near 16N, 30W at 144 still as a TD. If this keeps up a few more runs, it would call for a lemon, especially with the CVs potentially impacted within only 5 days.

Actually, with rather strong support by the Euro and Icon, some support by the CMC and JMA, and on/off support by the UKMET, I feel that if the Euro/Icon were to hold onto this at 12Z and if the UKMET were to get it back, it would then already be lemon-worthy even if the GFS still doesn’t have it.

[kevin]

A few 06z Euro ensemble members have a new system [6 members (~12%)] that wasn't there yet before: a subtropical system off the US coast. The other CV signal is also still there with 12 members (24%).

[cajungal]

A few 06z Euro ensemble members have a new system [6 members (~12%)] that wasn't there yet before: a subtropical system off the US coast. The other CV signal is also still there with 12 members (24%).

https://i.imgur.com/CzgEWCL.png

So odd to see absolutely nothing near the Caribbean or Gulf this time of the year, not even a single piece of spaghetti

[Category5Kaiju]

Never know about the long trackers we have had many hurricanes in the past that formed in early to mid Sept that came across the Atlantic I think of Hugo and I think Fran just to name a few. Too early to say Cape Verde is closed!

Yes but just different pattern. We would need to get a strong Bermuda ridge in place

This is true, and as always steering patterns are extremely fickle and are very sensitive to even the slightest changes in ridge/trough orientation, timing, magnitude, etc. (as we saw with Erin). And, blockbuster CV hurricanes are much less common than fish CV hurricanes.

But at least based on that one Euro run, it has this as the steering pattern:


That's quite the ridging in place.

[Teban54]

A few 06z Euro ensemble members have a new system [6 members (~12%)] that wasn't there yet before: a subtropical system off the US coast. The other CV signal is also still there with 12 members (24%).

https://i.imgur.com/CzgEWCL.png

So odd to see absolutely nothing near the Caribbean or Gulf this time of the year, not even a single piece of spaghetti

Given the EPAC outbreak in the short term, that's hardly surprising.

However, EPAC activity is often correlated with Atlantic activity, especially in the western half of the basin, a handful weeks later.

[LarryWx]

The 12Z Icon is another run with a far E MDR TD. It comes off Africa Fri night and is already a TD on Sat/Sat night.

Edit: This then becomes a TS moving WNW, implying a likely safe recurve from the US eventually though not for awhile later.

[TomballEd]

Never know about the long trackers we have had many hurricanes in the past that formed in early to mid Sept that came across the Atlantic I think of Hugo and I think Fran just to name a few. Too early to say Cape Verde is closed!

Yes but just different pattern. We would need to get a strong Bermuda ridge in place

This is true, and as always steering patterns are extremely fickle and are very sensitive to even the slightest changes in ridge/trough orientation, timing, magnitude, etc. (as we saw with Erin). And, blockbuster CV hurricanes are much less common than fish CV hurricanes.

But at least based on that one Euro run, it has this as the steering pattern:
https://i.imgur.com/Wnm7aCz.png

That's quite the ridging in place.

It is heading NW, it looks like the Bermuda ridge is not big/strong enough to prevent a recurve. Even an op 2 weeks+ out is little more than an ensemble control run. It would mean a storm on September 10, peak of the season.

[HurricaneBelle]

A few 06z Euro ensemble members have a new system [6 members (~12%)] that wasn't there yet before: a subtropical system off the US coast. The other CV signal is also still there with 12 members (24%).

https://i.imgur.com/CzgEWCL.png

So odd to see absolutely nothing near the Caribbean or Gulf this time of the year, not even a single piece of spaghetti

Yep, you have to go back all the way to......uh, last year.

[LarryWx]

Other 12Z runs:
-GFS still doesn’t have a TC from the far E MDR AEW. However, it does now have a weak reflection at the sfc as well as upper level vorticity clearly showing up. So, this is a hint that the GFS may in runs soon start showing this as a closed sfc low.

-CMC has nothing unlike prior runs

-UKMET (coming out late), Euro, and JMA still yet to be released

Edit:
-UKMET is 2nd run in a row without it
-Euro: dropped it

So, as of now, only the Icon has it pending the JMA.

Edit: JMA still has it. So, just Icon and JMA now.

[Category5Kaiju]

Interesting.

 https://x.com/WeathermanAAA_/status/1960410217826673034

[LarryWx]

The 12Z Icon is another run with a far E MDR TD. It comes off Africa Fri night and is already a TD on Sat/Sat night.

Edit: This then becomes a TS moving WNW, implying a likely safe recurve from the US eventually though not for awhile later.

Happy Hour runs:
-Unlike today’s prior 3 Icon runs, the new Icon has hardly anything, similar to the 12Z Euro/CMC.
-GFS still has almost nothing though there’s still some upper level vorticity.
-Thus, as of now, the only major op latest run with a TC from this is the JMA (12Z).

[WeatherBoy2000]

The 12Z Icon is another run with a far E MDR TD. It comes off Africa Fri night and is already a TD on Sat/Sat night.

Edit: This then becomes a TS moving WNW, implying a likely safe recurve from the US eventually though not for awhile later.

Happy Hour runs:
-Unlike today’s prior 3 Icon runs, the new Icon has hardly anything, similar to the 12Z Euro/CMC.
-GFS still has almost nothing though there’s still some upper level vorticity.

There's still marginal eps support for something around the turn of the month, but it looks like you have to go later into September for things to pick up more. This reflects the euro weeklies which is showing well below average ace for the first week and then progresses to well above normal by the end of the month.

[LarryWx]

There's still marginal eps support for something around the turn of the month, but it looks like you have to go later into September for things to pick up more. This reflects the euro weeklies which is showing well below average ace for the first week and then progresses to well above normal by the end of the month.

Further to what WxBoy just said about the EWs:

Today’s Euro Weekly run not only has the most active 9/15-21 ACE yet, it is the 1st run with 9/22-8 and that is even more active than 9/15-21! It has the quietest Sep week as the 1st one and the noisiest week as the 4th one. That resembles Sep of 2024 somewhat because then the quietest weeks of ACE in Sep were the 1st (0) and 3rd (0) while the 4th had the noisiest by far with AN ACE (18.1). The 2nd had 6.1.

Today’s EW ACE Sep progs vs very active 20 yr climo
1-7: 4.5 (.3)
8-14: 11.3 (.7)
15-21: 20.4 (1.3)
22-28: 22.4 (1.6)

So, today’s vs climo is despite a very quiet 1st week and still BN 2nd week progging the 1st 4 weeks of Sept at 58.6, which compares to only 24.2 in 2024 and ~the active 30 year climo of ~60.

To compare, look at what I posted on 8/27/24:

Today’s Euro Weeklies could be nicknamed “A Tale of Two Seasons”:

- Weeks 1-3 (9/2-22): remain only at ~50% of climo overall. These haven’t changed much for days other than a gradual decline.

- Week 4 (9/23-29/new week “on the block”): the first forecast for that week is for 120% of climo and it follows the prior week’s modest 70%. So, it’s seeing some kind of sudden change. If it were a reversion to climo, it would be only at 100%, not 120%. Also, this is the first time there has been any week at 120%+ since the 8/16 run. Will be interesting to follow.

[kevin]

The most active short-term Euro ensemble so far with 24 members (47%) showing an active CV disturbance at +144 hr (aka within the next 6 days). However, 06z yesterday was also a relatively active ensemble and support waned afterwards so we'll see if this stays in the upcoming ensembles.

[TomballEd]

The most active short-term Euro ensemble so far with 24 members (47%) showing an active CV disturbance at +144 hr (aka within the next 6 days). However, 06z yesterday was also a relatively active ensemble and support waned afterwards so we'll see if this stays in the upcoming ensembles.

https://i.imgur.com/ixf0t7V.png

Long way to travel this time of year w/o the recurve, longer term, I'd wonder/be concerned with any EPS members that have the wave but haven't developed it yet. Erin was really the only cool satellite storm this year, I'd take another.

[LarryWx]

Though support has waned significantly since all but the GFS had it on Monday, the 0Z UKMET brought the E MDR AEW back from the dead (albeit with later TCG) with a minimal TS due to a strong pressure gradient below a rather strong Azores high moving WNW:

NEW TROPICAL CYCLONE FORECAST TO DEVELOP AFTER 156 HOURS
FORECAST POSITION AT T+156 : 15.6N 33.8W

LEAD CENTRAL MAXIMUM WIND
VERIFYING TIME TIME POSITION PRESSURE (MB) SPEED (KNOTS)
-------------- ---- -------- ------------- -------------
1200UTC 03.09.2025 156 15.6N 33.8W 1010 34
0000UTC 04.09.2025 168 16.9N 35.9W 1011 35
——-

But 0Z GFS/Icon and probably CMC have nothing.