ATL: ISAIAS - Post-Tropical - Discussion

[cainjamin]

Looking a lot better this afternoon. Convection is starting to pop a lot more on the western edge of the broad gyre. The GFS was favouring cyclogenesis on the eastern and northern side of the large circulation which down the road looked to cause more dry air incursions from the southeast. Forming on the western side will likely help to protect 92L a little bit more from the dry air, but may also make it more of a landfall risk along the lesser and greater Antilles as it will likely move a little more westerly. Needless to say, it's going to be an interesting feature to track over the next few days.

[St0rmTh0r]

Does 92L already have a closed circulation?

No way to tell for sure without scans. Last visible shows it wrapping up more and actually looks like the circulation got a little bigger.

well I mean the winfield is closed and the morning ASCAT showed an elongated but defiend circ. Then Visible as you mentioned.

So overall yes it has a closed circ. but convection needs to organize more.

It's wait and see now its crossing 50W so theres that too.

[Florida1118]

I'd say upgrade by this time tomorrow if the trend continues, it looks like the convection is finally starting to consolidate from all directions over the last several hours.

A couple hours ago you said “Every season it seems we have at least one almost-there wave that seems almost 100% sure to develop, model support etc only to not quite get there, based on the trends this might be this season's”...only to now say the exact opposite trend

[DestinHurricane]

One suite of models is not a trend.

[HurricaneAndre2008]

[HurricaneAndre2008]

There better not be any funny business at the nhc next outlook.

[toad strangler]

One suite of models is not a trend.

And neither is five runs in a row into the North Atlantic

[HurricaneAndre2008]

Pressure dropping on the approach of the wave at rye buoy near 53W with some good winds too.

[HurricaneEnzo]

I'm not seeing what everyone else is. This still looks bad. Not really much more organized than it was earlier today. A huge circulation with spotty areas of convection showing no real signs of life. Still a long way to go.

https://www.tropicaltidbits.com/sat/sat ... t=vis-swir

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[Aric Dunn]

There is little to no way this misses the islands.. it would need to move NW.. effect start coming into babados by morning.

[HurricaneAndre2008]

Just need that defined circulation.
000
ABNT20 KNHC 272314
TWOAT

Tropical Weather Outlook
NWS National Hurricane Center Miami FL
800 PM EDT Mon Jul 27 2020

For the North Atlantic...Caribbean Sea and the Gulf of Mexico:

Shower activity associated with a low pressure area located about
850 miles east of the Windward Islands has again become a little
better organized, however the low's circulation remains broad
without a well-defined center of circulation. Environmental
conditions are expected to become somewhat more conducive for
development, and a tropical depression or tropical storm is likely
to form during the next couple of days while the system moves
west-northwestward at 15 to 20 mph and approaches the Leeward
Islands. Regardless of development, locally heavy rains and gusty
winds are likely across portions of the Leeward Islands on Wednesday
and will spread westward to the Virgin Islands and Puerto Rico
Wednesday night and Thursday. Interests on these islands should
continue to monitor the progress of this system, and tropical storm
watches or warnings could be required for portions of the area on
Tuesday.
* Formation chance through 48 hours...high...70 percent.
* Formation chance through 5 days...high...80 percent.

$$
Forecaster Berg

[Hammy]

I'd say upgrade by this time tomorrow if the trend continues, it looks like the convection is finally starting to consolidate from all directions over the last several hours.

A couple hours ago you said “Every season it seems we have at least one almost-there wave that seems almost 100% sure to develop, model support etc only to not quite get there, based on the trends this might be this season's”...only to now say the exact opposite trend

It still might be, there's no guarantee it'll develop--but you never know what that wave is until after because it's always 100% certainty that it'll develop, right up until it doesn't.

[RT23]

There is little to no way this misses the islands.. it would need to move NW.. effect start coming into babados by morning.

It is huge!! Barbados by morning you say? Waiting to see what the 8pm Two says. We been monitoring closely!

[HurricaneEnzo]

Just need that defined circulation.
000
ABNT20 KNHC 272314
TWOAT

Tropical Weather Outlook
NWS National Hurricane Center Miami FL
800 PM EDT Mon Jul 27 2020

For the North Atlantic...Caribbean Sea and the Gulf of Mexico:

Shower activity associated with a low pressure area located about
850 miles east of the Windward Islands has again become a little
better organized, however the low's circulation remains broad
without a well-defined center of circulation. Environmental
conditions are expected to become somewhat more conducive for
development, and a tropical depression or tropical storm is likely
to form during the next couple of days while the system moves
west-northwestward at 15 to 20 mph and approaches the Leeward
Islands. Regardless of development, locally heavy rains and gusty
winds are likely across portions of the Leeward Islands on Wednesday
and will spread westward to the Virgin Islands and Puerto Rico
Wednesday night and Thursday. Interests on these islands should
continue to monitor the progress of this system, and tropical storm
watches or warnings could be required for portions of the area on
Tuesday.
* Formation chance through 48 hours...high...70 percent.
* Formation chance through 5 days...high...80 percent.

$$
Forecaster Berg

NHC agrees with me. Only marginally better organized than it was earlier if at all.

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[Hybridstorm_November2001]

Unless it doesn't fully orangize at all, I hope everyone realizes this trend isn't a good thing. The longer a storm takes to intensify the more likely it is to drift westward along with the low to mid-level tropical flow i.e. towards Mainland North America.

[SFLcane]

Aric, NHC confirms what you have been saying this afternoon. Slowly be surely getting better organized.

[Cpv17]

Unless it doesn't fully orangize at all, I hope everyone realizes this trend isn't a good thing. The longer a storm takes to intensify the more likely it is to drift westward along with the low to mid-level tropical flow i.e. towards Mainland North America.

Yep. If this gets in the Bahamas, western Caribbean, or Gulf then we could be dealing with a major problem because it seems those areas are usually very favorable.

[Hurricaneman]

What I’m thinking track wise is between the 18zGFS and 12zeuro with an intensity similar to the GFS Para which we may be getting slight hints that the gfs may be trending towards the GFS Para

As for a forecast right now here goes nothing

24hrs. TD 35mph
48hrs. TS. 50mph
72hrs. TS. 70mph
96hrs. C1. 85mph
120hrs. C3. 115mph

[AdamFirst]

I'd say between all the model runs, some sort of organized storm will be in place over the Antilles on Wednesday to Thursday. Likely weak but in these occasions flash flooding is always the primary concern.

The posts in this forum are NOT official forecast and should not be used as such. They are just the opinion of the poster and may or may not be backed by sound meteorological data. They are NOT endorsed by any professional institution or STORM2K. For official information, please refer to products from the National Hurricane Center and National Weather Service.

[Nimbus]

Wxman57 said we would have to wait until at least tomorrow for a depression declaration.
Models have swung the track west as expected, South Florida is targeted for the 18z GFS run then the gulf.
The system is elongated and with the dry air I was favoring the southwest lobe of the circulation for the eventual center. Both HWRF and GFS show the center gaining over a degree or more of latitude quickly after formation so the Leeward islands may need watches and warnings.