2024 Global Model Runs Discussion (Out thru day 16)

[Teban54]

It’s rather odd the NHC gave the lemon only 0% to10% this morning in the east Atlantic. Discounting the GFS ideas as bogus maybe.

That's a different system. The 0/10 is the monsoon trough disturbance that's currently in Eastern Atlantic that had been on the TWO for days, and most models don't do much with it (except 6z GFS). The CV long-tracker that has been on many recent GFS runs comes from a wave that will exit Africa around September 10, which has not been introduced to the TWO yet.

[MEANINGLESS_NUMBERS]

06Z GFS has two hurricanes hitting Bermuda on Sept 19 (989 mbar) and then Sept 21 (958 mbar), almost exactly 10 years since Hurricanes Fay and Gonzalo made landfall in the same week. Spooky.

[MarioProtVI]

12z GFS and CMC both dropped the Tuesday wave in line with the Euro. Go figure with how hostile this season has been

[Pelicane]

GFS drops the MDR long-tracker completely. Still quiet as can be in the deep tropics.

[gatorcane]

Alot of dry, stable air across the northern Atlantic MDR with a strong SAL surge next week, which is likely why it is no longer developing the wave:

[Hypercane_Kyle]

GFS drops the MDR long-tracker completely. Still quiet as can be in the deep tropics.

Followed the 00z Euro in that regards. I wonder what's the record for least active September in history, 2024 will likely challenge it.

[ConvergenceZone]

GFS drops the MDR long-tracker completely. Still quiet as can be in the deep tropics.

Followed the 00z Euro in that regards. I wonder what's the record for least active September in history, 2024 will likely challenge it.

yea I'm pretty much moving out of tropics watching mode and looking forward to winter in California. I'll check back here towards the end of the month and see if there's anything going on at all.. Maybe in early October the models will show something lol.

[MarioProtVI]

12z EURO still doesn’t like/barely develop it at all.

[Teban54]

12z EURO still doesn’t like/barely develop it at all.

It does seem to deepen it slightly at 216-240 hrs past 50W, though. Note that a lot of GFS runs earlier also had the system only get going in the central or western MDR. I'm not sure why Euro remains on a much more northerly track than GFS even without greater short-term intensity (which was usually considered a Euro bias), however.

[aspen]

The operational global runs almost totally drop the new MDR system. What a surprise.

At this rate, we might have zero active storms on peak season day. When was the last time this happened?

[Teban54]

12z ensembles, take them as you wish.

[Teban54]

After a brief dip that was 12z, 18z GFS comes back with the development of both the 9/10 MDR wave and the current 0/10 Eastern Atlantic system ahead of it. Unlike most of its recent runs, though, this time it makes the leading wave the dominating system and a recurving hurricane. The "long-tracker" ends up badly sheared as a result.

[MetroMike]

Full run of 18z GFS is almost comical in the long range as it turns into a m hurricane going south and west back toward conus. Nice entertainment from the broken models.

[Teban54]

Yankee 1935, is that you?

(Seriously, 6 days as an MH in the open Atlantic would already be enough to wipe out the ACE deficit of this season, much less one that's moving due south.)

[Stormlover70]

Yankee 1935, is that you?

(Seriously, 6 days as an MH in the open Atlantic would already be enough to wipe out the ACE deficit of this season, much less one that's moving due south.)

https://i.postimg.cc/jd9TrpW5/gfs-mslp-pcpn-atl-fh6-384.gif

or Jeanne 04.

[gatorcane]

The global models are showing a large mid to upper-level low pressure area forming along the mid-Atlantic and SE coast of the United States in the medium to long-range. For example, here is the 00Z ECMWF 500MB heights animation from 144 to 240 hours. This pattern would block anything coming in from the east towards Florida and the SE US coastline, good timing considering we are at the peak now:

[Teban54]

0z EPS still shows moderate MDR activity. I find this run interesting for two reasons:

1. Ensembles now have roughly equal support for both the Eastern Atlantic trough (current 0/30 AOI) and the following 9/10 wave. This wasn't the case as recently as 12z EPS.
2. Tracks have shifter further SW overall, despite still being on a recurve.

6z GEFS shows similar things. I'd say the end of this map is pretty busy all things considered, and support for at least one system to develop seems to have slightly increased (though I haven't counted the numbers yet). It's also hinting at another eastern MDR system towards the end of this run.

[Ubuntwo]

12z GFS shows two storms developing out of the monsoon trough breakdown (within 4-5 days). The second is not from the wave forecast to emerge, rather, from a lobe of the trough itself. This is a solution the ICON has hinted at. Anecdotally, these breakdowns usually only go to produce one system, even if multiple are modeled.

[gatorcane]

The 12Z GFS looks to develop a major hurricane out over the open Atlantic recurving it north into a large weakness over the North-Central Atlantic. 120 to 240 hours below:

[cheezyWXguy]

If there’s anything I can gather from looking at all these runs, it’s the models are depicting several areas of low pressure forming from the monsoon trough and/or its interactions with passing tropical waves, and it they are struggling to resolve a singular outcome. Pick a run at random and it’s a different vort that becomes dominant, and the erratic tracks seem to due in part to fujiwara interactions with the less dominant vorts. Reminds me a lot of Rene and Paulette back in 2020. Until something consolidates I don’t think we’re going to have much of an idea on track/intensity