2021 Global Model Runs Discussion (Out thru day 16)

[SFLcane]

Whoa, those are some pretty potent GEFS ensemble signals for the potential WCAR disturbance around the 20th....and it looks to take that classic late season NE curve toward, you guess it....Florida.

Yeah 4-5 members having some fun there.

[SFLcane]

First run bringing in the time on the Gefs. Well see if it lasts

[Ubuntwo]

12z GFS tracks the second wave across the Caribbean unlike the 6z but struggles with a poor environment. Dry air and shear. First wave does not have that issue so proximity to land is its inhibiting factor.

[LarryWx]

Whoa, those are some pretty potent GEFS ensemble signals for the potential WCAR disturbance around the 20th....and it looks to take that classic late season NE curve toward, you guess it....Florida.

Keep in mind that S FL climo shows that before dropping off pretty rapidly, the threat frequency is about as high as for any 5 day period in the entire season during 10/17-21. Check out past seasons and you'll see this. So, imo, this period needs to be especially monitored in light of the 12Z GEFS.

[Ubuntwo]

 https://twitter.com/AndyHazelton/status/1448326343624626178

[gatorcane]

12z GEFS much more excited about the earlier timeframe as well. Go figure today everything is getting shifted forward.

This just tells me that something is going to pop up soon. I cannot envision nothing happening down there with all the positive variables.

https://i.ibb.co/qFPYHx9/gfs-ememb-lowlocs-watl-34.png

I agree I think something is going to happen down there in the next 2 weeks, could this be it?

120-228 hour GFS loop:

[SFLcane]

I am hesitant given the other guidance but this could be the trigger. Low probability for now until other guidance comes onboard. Just 0 consistency

[Ubuntwo]

~40% of 12z EPS members develop in the western basin thru day 15. Even more have deep surface lows cutting across the FL peninsula, but most are broad and elongated so probably not TCs.

[aspen]

The 12z GEFS and EPS have decent support for both Caribbean systems — the one forming near the Yucatán and the one coming from the west MDR tropical wave. Both possible systems have trackable origins and will coincide with the enhanced CCKW, so already they’re a lot more plausible than some of the GFS’s modeled systems from earlier in the month.

[Teban54]

The 12z GEFS and EPS have decent support for both Caribbean systems — the one forming near the Yucatán and the one coming from the west MDR tropical wave. Both possible systems have trackable origins and will coincide with the enhanced CCKW, so already they’re a lot more plausible than some of the GFS’s modeled systems from earlier in the month.

Can the Caribbean even support two tropical cyclones at the same time?

[Category5Kaiju]

The 12z GEFS and EPS have decent support for both Caribbean systems — the one forming near the Yucatán and the one coming from the west MDR tropical wave. Both possible systems have trackable origins and will coincide with the enhanced CCKW, so already they’re a lot more plausible than some of the GFS’s modeled systems from earlier in the month.

Can the Caribbean even support two tropical cyclones at the same time?

It’s likely that especially if one is a major hurricane its outflow channels would severely shear the other and keep the other relatively weak, but as we saw with Eta/Iota and Dean/Felix, the Caribbean can support major hurricanes in succession

[Nimbus]

Some years we don't get the late season storms out of the Caribbean.
West coast of Florida is usually in the cone.
The Tampa Bay hurricane of 1921 (also known as the 1921 Tarpon Springs hurricane) was the most recent major hurricane to strike the Tampa Bay Area.
Maybe start the season over posts for Texas.

[Hammy]

The 12z GEFS and EPS have decent support for both Caribbean systems — the one forming near the Yucatán and the one coming from the west MDR tropical wave. Both possible systems have trackable origins and will coincide with the enhanced CCKW, so already they’re a lot more plausible than some of the GFS’s modeled systems from earlier in the month.

Can the Caribbean even support two tropical cyclones at the same time?

It’s likely that especially if one is a major hurricane its outflow channels would severely shear the other and keep the other relatively weak, but as we saw with Eta/Iota and Dean/Felix, the Caribbean can support major hurricanes in succession

I doubt it would support two being active simultaneously, unless you have a situation where one is entering the Gulf through the Yucatan Channel as a second one is entering through the Lesser Antilles.

[Ubuntwo]

I doubt it would support two being active simultaneously, unless you have a situation where one is entering the Gulf through the Yucatan Channel as a second one is entering through the Lesser Antilles.

Happened last year with Marco/Laura. (Gamma and pre-Delta also coexisted in the Caribbean)

[Category5Kaiju]

6z GEFS definitely hinting at some tropical system forming in the WCAR around the 20th and taking that NE turn toward the Florida vicinity by a few days later. Pretty solid signal too, I think this may not be a phantom storm.

[Ubuntwo]

6z GEFS definitely hinting at some tropical system forming in the WCAR around the 20th and taking that NE turn toward the Florida vicinity by a few days later. Pretty solid signal too, I think this may not be a phantom storm.

Not a phantom because the incipient disturbance is trackable. The GFS does have a tendency to overamplify disturbances in the Caribbean (convective feedback) which is what some suspect may be going on. It has gotten better over the past couple years though.

[SFLcane]

GFS has a sloppy hybrid system moving over SFL ahead of a front.

= Some rain

[SFLcane]

18z Gefs did increase though…

[SFLcane]

Interesting…

[Category5Kaiju]

After the 20-22nd disturbance leaves the West Atlantic, some GEFS ensemble members hint that a second system spawned from an MDR wave could get going in the E/C Caribbean and move westward merely a week or so afterwards. Considering the Caribbean's ssts and UOHC levels, I don't like this setup one bit.