Area in the Northwestern Caribbean Sea

[NDG]

Indeed a trend towards increased vorticity by the 18z Euro for the same time Saturday morning.

[lsuhurricane]

Likewise, roughly double the ensemble members indicate development comparing 144 hrs @ 18z vs 150 hrs @ 12z.

[tolakram]

Interesting..

The swirl I was watching is still swirling.

https://rammb-slider.cira.colostate.edu/?sat=goes-16&sec=full_disk&x=15224&y=8614&z=4&angle=0&im=12&ts=1&st=0&et=0&speed=130&motion=loop&maps%5Bborders%5D=white&lat=0&p%5B0%5D=cira_proxy_visible&opacity%5B0%5D=1&pause=0&slider=-1&hide_controls=0&mouse_draw=0&follow_feature=0&follow_hide=0&s=rammb-slider&draw_color=FFD700&draw_width=6

[skyline385]

18Z GEFs with a ton of activity in the Gulf

[weeniepatrol]

The swirl I was watching is still swirling.

Good observation

 https://twitter.com/DerekOrtt/status/1562250521767038976

[tolakram]

At some point someone has to mention that this has to get through the graveyard. I figure I'll do it so someone can remind us that in the last 100 years there have been at least 3 storms that actually developed in that area, and maybe this is the year! If we get a proper invest out of this I figure it will be a long ride.

[weeniepatrol]

At some point someone has to mention that this has to get through the graveyard. I figure I'll do it so someone can remind us that in the last 100 years there have been at least 3 storms that actually developed in that area, and maybe this is the year! If we get a proper invest out of this I figure it will be a long ride.

Interestingly ensembles indicate the graveyard should be less of an issue given these 850mb-wind means.





Fact that it takes a week to make it to Jamaica on the GFS is indicative of the benign, and not oppressive, trade flow

0z TWD:

A tropical wave is along 56W, from 04N to 20N, moving westward at
5-10 knots. Scattered moderate convection is in the region of the
monsoon trough from 04N to 10N between 50W and 60W.

More typical of the WCar than western MDR

[lsuhurricane]

Great point Weenie - also, it’s pretty clear that the jumping off point for this won’t actually occur for another 3-4 days. So development won’t technically be in the “East Caribbean”

[skyline385]

Here's an interesting thread from Papin on why the GEFS has more NE members than the op GFS. The GEFS is still running off the original FV3 implementation, the one which wasn't prone to spawning ghost systems everywhere and hence also handles TCG differently than the op GFS. GEFS is basically more conservative and has less false alarms than the op GFS.

 https://twitter.com/pppapin/status/1562251226581852164




 https://twitter.com/AndyHazelton/status/1562257093629018112

[sma10]

Great point Weenie - also, it’s pretty clear that the jumping off point for this won’t actually occur for another 3-4 days. So development won’t technically be in the “East Caribbean”

Yes even the aggressive GFS doesn't really ramp up until the central Caribbean

[NotSparta]

Here's an interesting thread from Papin on why the GEFS has more NE members than the op GFS. The GEFS is still running off the original FV3 implementation, the one which wasn't prone to spawning ghost systems everywhere and hence also handles TCG differently than the op GFS. GEFS is basically more conservative and has less false alarms than the op GFS.

https://twitter.com/pppapin/status/1562251226581852164?s=20&t=AKAzEOwQ0e6jBPzoc-ICvg

https://twitter.com/AndyHazelton/status/1562257093629018112?s=20&t=AKAzEOwQ0e6jBPzoc-ICvg

Oh boy, GFSv15 gives me Vietnam flashbacks of when models refused to develop anything back in 2020

[Category5Kaiju]

Here's an interesting thread from Papin on why the GEFS has more NE members than the op GFS. The GEFS is still running off the original FV3 implementation, the one which wasn't prone to spawning ghost systems everywhere and hence also handles TCG differently than the op GFS. GEFS is basically more conservative and has less false alarms than the op GFS.

https://twitter.com/pppapin/status/1562251226581852164?s=20&t=AKAzEOwQ0e6jBPzoc-ICvg

https://twitter.com/AndyHazelton/status/1562257093629018112?s=20&t=AKAzEOwQ0e6jBPzoc-ICvg

Oh boy, GFSv15 gives me Vietnam flashbacks of when models refused to develop anything back in 2020

But in 2020, didn't accurate and efficient model inputs suffer due to the pandemic? That's what I at least heard back then

[NotSparta]

Here's an interesting thread from Papin on why the GEFS has more NE members than the op GFS. The GEFS is still running off the original FV3 implementation, the one which wasn't prone to spawning ghost systems everywhere and hence also handles TCG differently than the op GFS. GEFS is basically more conservative and has less false alarms than the op GFS.

https://twitter.com/pppapin/status/1562251226581852164?s=20&t=AKAzEOwQ0e6jBPzoc-ICvg

https://twitter.com/AndyHazelton/status/1562257093629018112?s=20&t=AKAzEOwQ0e6jBPzoc-ICvg

Oh boy, GFSv15 gives me Vietnam flashbacks of when models refused to develop anything back in 2020

But in 2020, didn't accurate and efficient model inputs suffer due to the pandemic? That's what I at least heard back then

Yeah, though I think v15 also had some issues with false negatives

[Nimbus]

Great point Weenie - also, it’s pretty clear that the jumping off point for this won’t actually occur for another 3-4 days. So development won’t technically be in the “East Caribbean”

Yes even the aggressive GFS doesn't really ramp up until the central Caribbean

Looks like the wind anomaly in the Caribbean is +4 to +6 , probably the SA shear we usually see will keep this from spinning up till western Carib. Four days out now from forecast consolidation so these models aren't totally in dreamland.

[skyline385]

Oh boy, GFSv15 gives me Vietnam flashbacks of when models refused to develop anything back in 2020

But in 2020, didn't accurate and efficient model inputs suffer due to the pandemic? That's what I at least heard back then

Yeah, though I think v15 also had some issues with false negatives

I am not 100% sure on the source but I remember reading that the ECMWF is more dependent on obs data and hence it took the biggest hit accuracy-wise in 2020. IIRC a lot of the accuracy issues were related to the ECMWF, that's not to say the GFS didn't bust either but it was doing much better than the ECMWF.

Also, here is a brilliant ELI5 from Papin on GFS vs GEFS

 https://twitter.com/pppapin/status/1562262446735142913

[Teban54]

At some point someone has to mention that this has to get through the graveyard. I figure I'll do it so someone can remind us that in the last 100 years there have been at least 3 storms that actually developed in that area, and maybe this is the year! If we get a proper invest out of this I figure it will be a long ride.

TC formation in the eastern Caribbean (I used the longitude of the western tip of Dominican Republic) in August and September since 1950:
- TS Gabrielle 2013: Formed on September 4, SSE or Puerto Rico
- TS Emily 2011: Formed on August 2, on the NW tip of Martinique
- C4 Gustav 2008: Formed on August 28, N of Venezuela
- C1 Ernesto 2006: Formed on August 24, N of Grenada
- TD 2003: Formed on August 21 and dissipated the next day, both in the middle of ECar
- TS Dean 2001: Formed on August 22, near USVI
- TD 1987: Formed on September 6, in the SE corner of ECar
- TD 1981: Formed on September 12, near the N coast of Columbia
- C4 Greta 1978: Formed on September 13, NE of Venezuela
- C2 Fifi 1974: Formed on September 14, far S of USVI
- C2 Francelia 1969: Formed on August 29, W of Grenada
- TS Gerda 1958: Formed on September 14, SW of Puerto Rico

So storms forming in ECar is actually not that rare, although there are more storms entering ECar and getting killed there. Interestingly, of the 12 TCs above, only one dissipated before reaching WCar, and the rest typically made landfall somewhere before dissipation (the exception being Dean 2001, which formed at the extreme NE corner of my search box and went OTS). Gustav and Greta went on to become majors in WCar.

[skyline385]

0Z ICON running slightly weaker

[LarryWx]

Per the following link, the E GOM at 87-90 F is currently running the hottest it has been in August since at the very least 2017 and likely is about as warm as it ever gets there. This is one reason the GFS is exploding this TC. Longterm average is closer to 86-87 F.

https://seatemperature.info/august/gulf ... ature.html

Recurving around the periphery of a ridge at that latitude there usually isn't much inhibiting development in September. The storms actually recurve into a higher pressure environment so that and the SST anomaly probably accounts for the intensity outlook. I'm just in denial because of the quiet August.

What's kinda interesting is that the Gulf was running much hotter last month and has actually cooled down a fair bit.

https://i.imgur.com/7nuPWnA.jpg

Indeed, much of the Gulf has cooled the last 30 days. But I was talking about the E Gulf just offshore FL, which has actually warmed slightly during the same period, including on the maps you showed. I checked this afternoon's SSTs in that area and saw 87-90+ F (30.5-32+ C) at every location and this covered areas that the 18Z GFS crossed and the SLP plunged 40 mb within a pretty short period (RI).

[skyline385]

0Z ICON ends much stronger and way SW, the GEFS members aiming for the Western Gulf could be potentially on to something.

[lsuhurricane]

Might be time to put the GFS out to pasture after this lack of consistency