ATL: DORIAN - Post-Tropical - Discussion

[galaxy401]

Yeah the NHC seems to be behind with this system. The first outlooks should have been issued a couple days ago. August 20th really is the date everything changes.

[AutoPenalti]

That is one very impressive structure. It still has a lot work to do. Needs to fight a ULL to its north west and dry air still a bit of an issue.

[NDG]

This is already at least a TD, I’ve seen worst looking elongated circulations being upgraded in the EPAC this year. The trusted Euro let the NHC down, like I mentioned earlier it has not being doing well recognizing low latitude waves this year in Atlantic.

[Kazmit]

It's going to need to gain quite a bit of latitude if it wants to make it north of the Greater Antilles. It seems like that's the track that will keep conditions the most favorable. The other possibilities are it gets shredded by Hispaniola or by shear in the eastern Caribbean.

[AutoPenalti]

A special advisory might be issued pretty soon. NHC are in no rush to raise chances or classify systems if there’s no immediate threat to land.

[TheStormExpert]

Tropical Tidbits Levi Cowan starting to hand it to the GFS for sniffing this out.

 https://twitter.com/tropicaltidbits/status/1164942356191354880

[gatorcane]

Yeah kudos to the GFS that is for sure. Euro completely missed it along with every other model. My guess is because of its small size so the other models missed it.

[Highteeld]

[tropicwatch]

Significant increase in 850mb vorticity with 99L.

[northjaxpro]

Yes indeed. GFS long range forecasting past 7 days has been so much.improved, not just only with the tropics, but with winter-time synoptics as well.

[Hammy]

Yeah the NHC seems to be behind with this system. The first outlooks should have been issued a couple days ago. August 20th really is the date everything changes.

They didn't trust the GFS with the others not developing, and for good reason as the model has a terrible history with phantom storms, even in the short range. It's a sort of crying wolf situation.

[gatorcane]

Looks to be gaining some latitude at the end of the loop:

https://www.tropicaltidbits.com/sat/sat ... roduct=vis

[cycloneye]

Recent satellite wind data indicate that a low pressure area has
formed in association with a tropical wave located about 1300
miles east-southeast of the Windward Islands. Additional
development of this system is possible during the next few days, and
a tropical depression could form late this weekend or early next
week as it moves generally westward to west-northwestward near 15
mph.
* Formation chance through 48 hours...medium...40 percent.
* Formation chance through 5 days...medium...50 percent.

[Siker]

Convection has pulsed down for the moment, which is fairly typical as we reach DMIN out there. I would guess this gets classified at 5AM given the lack of strong convection right now and the fact it was only designated as an invest this morning, although it may already meet the criteria of a TC. Nice banding structure visible right now.

[Highteeld]

[DioBrando]

Called it.

I seriously wonder if this (likely Erin) would be our first major of the year.

[abajan]

NOW, this one has my attention right off the bat. As Aric stated I think we FINALLY may have our first true and real and genuine MDR system that will actually have an opportunity to fully mature into a potential formidable tropical cyclone .

Dry air should not be a crippling inhibitor with.99L this time around. Origin of this system tied to the ITCZ initially.

On a side note, I also am impressed with the tropical wave behind 99L just off the African coast. That will be the.next invest soon. The North Atlantic basin looks to have finally.awakened folks, ,after a long summer slumber. Just in time for the approach of the peak time of the season

Mark Sudduth has basically been warning about the probability of the proverbial "lid" coming off in his last several YouTube videos. He may not be a meteorologist, but he seems to know what he's talking about.

[abajan]

:uarrow: Yes indeed. GFS long range forecasting past 7 days has been so much.improved, not just only with the tropics, but with winter-time synoptics as well.

The GFS has definitely improved this year when compared to former years. The other day it was right on the money in showing Barbados and the Windward Islands would get rain, over a week in advance. Someone's been doing some tweaking!

[HurricaneAndre2008]

Global Tropics Hazards and Benefits Outlook Discussion
Last Updated: 08.23.19 Valid: 08.21.19 - 09.03.19
The original outlook remains largely on track, with dynamical model forecasts converging around the earlier GEFS/CFS perspective regarding a Kelvin wave tracking rapidly across the Indian Ocean to the Maritime Continent over the next 10-15 days. There is some projection of this feature onto the RMM Index, although the phase speed of the eastward propagating intraseasonal envelope is near the boundary of characteristic MJO and Kelvin wave events (period of approximately 20-25 days).

NHC is currently monitoring a disturbance over the Bahamas, giving it a 70% (90%) chance of becoming a TC over the next 48 hours (5 days) off the Southeast coast, resulting in a high risk for TC formation being introduced here. NHC is also monitoring a tropical wave near 10N/43W, with 40% (50%) chances of development over the next 48 hours (5 days), which corresponds to moderate confidence of TC formation in this outlook. In the East Pacific, Tropical Storm Ivo formed on the 21st, verifying the high risk from the original outlook that is subsequently dropped from this update. The moderate risk of TC formation area from the original outlook may have missed its chance to develop, as the Central Pacific Hurricane Center now gives it a near 0 (30%) chance of forming over the next 48 hrs (5 days), resulting in it being left off the update. Tropical Storm Bailu formed over the West Pacific on the 21st and is forecast to track across Taiwan over the weekend. JTWC is monitoring another system (99W) near 7N/145E that has a low chance of developing in the next 24 hours, but dynamical model guidance is more supportive of development over the weekend or early next week, resulting in a moderate confidence of TC formation area being included east of the Philippines.

As anticipated, wind shear over the Atlantic main development region (MDR) has relaxed in the wake of the Kelvin wave passage. Broad subsidence continues to be forecast over the MDR consistent with the low-frequency state. Model guidance is more bullish than Tuesday on possible TC formation in the vicinity of Cape Verde during Week-2, resulting in moderate confidence of cyclogenesis for a region roughly between 10-20N and 50W and the African coastline. The west-southwest to east-northeast orientation of the TC formation focus suggests a relatively southern track for the system around the base of the subtropical high, supporting a potential track toward the Lesser Antilles during the first third of September. U.S. interests should also pay close attention to subsequent updates of this outlook for more information as the system possibly comes closer to becoming a reality. The Week-2 West Pacific TC formation area is maintained, while any activity southeast of Hawaii appears less likely resulting in that area being downgraded from the graphic.

Above- and below-normal precipitation regions from Tuesday are updated to reflect the latest guidance regarding TC tracks in addition to dynamical model precipitation forecasts.

[abajan]

Looks to be gaining some latitude at the end of the loop:

https://www.tropicaltidbits.com/sat/sat ... roduct=vis

I thought the same thing. Could be a wobble or a genuine change in direction. IDK