ATL: ISAIAS - Post-Tropical - Discussion

[FLpanhandle91]

The lowest pressure reading is not true center I guess.

[StPeteMike]

With the shear seeming to be diminishing from the picture, the possibility of this storm becoming a major is definitely above 60% in my opinion. I don’t see anything really stopping it at the moment from doing so.

[FireRat]

This hurricane also brings to mind one historic storm from the faaaaar past considering today is it's anniversary...

The 1715 Hurricane, which decimated a Spanish treasure fleet off the coast of Florida on July 31, 1715, killing around 1,500 sailors, and wrecking the ships near and on the treasure coast. That one may have been quite strong and taken a similar track to what Isaias might do (Pass near eastern FL) and around the same time of the season.

[sgastorm]

Movement appears to be due NW according to recon (310ish°)

I (or more correctly, Google Earth Pro) calculate a motion of 290 degrees between the two fixes. This could just be a wobble, however, and not indicative of longer term motion.

[Hypercane_Kyle]

Normal season: Hispaniola landfall + weak tropical storm + fast forward speed + shear = opening up back into a wave or dissipation.

2020 season: Hispaniola + weak tropical storm + fast forward speed + shear = Explosive deepening to a hurricane??

[FLpanhandle91]

Movement appears to be due NW according to recon (310ish°)

I (or more correctly, Google Earth Pro) calculate a motion of 290 degrees between the two fixes. This could just be a wobble, however, and not indicative of longer term motion.

I'm a bit confused. Recon deployed a dropsonde at what they're calling the center at 20.4N 72.5W. However, the lowest pressure was found at 20.3N 72.25W. So yes that would be a bit further south and west.

[CyclonicFury]

Flight level winds were a lot lower this pass, though SFMRs were slightly higher.

[sponger]

Movement appears to be due NW according to recon (310ish°)

I (or more correctly, Google Earth Pro) calculate a motion of 290 degrees between the two fixes. This could just be a wobble, however, and not indicative of longer term motion.

Corresponds to what the difficult to read IR seems to be showing. Tomorrow is going to be interesting to say the least.

[storminabox]

I’m really starting to monitor this storm in NE Mass.

[FLpanhandle91]

Pretty easy to see the center and an eye trying to form on IR right now.

https://rammb-slider.cira.colostate.edu ... 312&y=1246

[sponger]

Movement appears to be due NW according to recon (310ish°)

I (or more correctly, Google Earth Pro) calculate a motion of 290 degrees between the two fixes. This could just be a wobble, however, and not indicative of longer term motion.

I'm a bit confused. Recon deployed a dropsonde at what they're calling the center at 20.4N 72.5W. However, the lowest pressure was found at 20.3N 72.25W. So yes that would be a bit further south and west.

That would be nearly 70 miles to the South!

[Weatherboy1]

Well just as I said several hours ago, what looked like a center reformation along the N coast of Hispanola and much less degradation from passing over the island meant intensity estimates would likely be too low. But even I’m surprised we have an 80 mph hurricane already. Time to watch wobbles and waypoints carefully now here in PBC FL. Models still (mostly) want to keep Isaias offshore. But not by much, and not all (esp when taking ensembles into account). Every move west of a forecast point increases our chance of at least getting grazed.

[Aric Dunn]

Movement appears to be due NW according to recon (310ish°)

I (or more correctly, Google Earth Pro) calculate a motion of 290 degrees between the two fixes. This could just be a wobble, however, and not indicative of longer term motion.

There is nothing to turn it yet. West to WNW motion is likely given the current setup....

remember models increase shear enough which forces the center to "keep up" with the lopsided convection. which intern keep a more WNW motion..

if shear does not increase in the short term then Isalsa tracking farther west before the turn is likely.

[FLpanhandle91]

Movement appears to be due NW according to recon (310ish°)

I (or more correctly, Google Earth Pro) calculate a motion of 290 degrees between the two fixes. This could just be a wobble, however, and not indicative of longer term motion.

There is nothing to turn it yet. West to WNW motion is likely given the current setup....

remember models increase shear enough which forces the center to "keep up" with the lopsided convection. which intern keep a more WNW motion..

if shear does not increase in the short term then Isalsa tracking farther west before the turn is likely.

Haven't found any dropsonde data that has any shear or dry air yet. Winds seem to be consistent from flight level to the surface.

[ConvergenceZone]

When the new forecast track/intensity is posted within the next 20 minutes or so, I'd appreciate ya if you can post the map....not staying up for the Euro, but am staying up for the next advisory in about 20 minutes or so.

[Cat5James]

Isaias certainly appears to be treking south of Inagua Islands.

[FireRat]

Normal season: Hispaniola landfall + weak tropical storm + fast forward speed + shear = opening up back into a wave or dissipation.

2020 season: Hispaniola + weak tropical storm + fast forward speed + shear = Explosive deepening to a hurricane??

Yeppers

[Jr0d]

I have never seen anything like this...instead of being sheared to an open wave/minimal storm by Hispaniola, Isaias just bounced of the mountains and became a hurricane. This is a scenerio that I would thought was impossible 12 to 36 hours ago.

I am seeing the overal movement still WNW to West, despite the NW 'jog' from the LLC that is indicated by the hurricane hunters.

We are running out of time(and distance) for this to miss Florida. There are definately indicators the ridge is stronger which of course means a track further west. I will not be surprised if Florida gets hurricane watches by 11am tomorrow if the current motion continues.

[FireRat]

Timing is everything in this business, but holy cow it's gonna be a nail-biting couple of days for FL, Bahamas and the Carolinas!

Watching the forward speed is going to be crucial IMO... any faster movement than expected will get this storm closer to or over Southeast FL. Bahamas will likely take a hit no matter the scenario, would come down to specific islands. Carolinas definitely in play if the storm follows the current speed and track.

Any slower movements from Isaias, on the other hand, would give more time for the trough to scoop it up, saving Florida and maybe even the Carolinas/East Coast if it stays just offshore. This feels like Matthew all over again, but so doggone early. I'd say Bertha 1996 could be one of the closest recent analogs looking at possible track and timing (but a bit more south and west than Bertha trekked before its NC landfall, and also 3 weeks later).

[TheDreamTraveler]

I'm still amazed at how fast Isaias is moving. 18mph still. Most canes in this area don't move that fast. At least it's not moving at 23mph anymore lol