ATL: ISAAC - Post-Tropical - Discussion

[WeatherGuesser]

News reports are talking about shutting down the oil platforms.

[Aric Dunn]

Still nw

[bella_may]

A mobile or a MS/Al line landfall looks very possible at this point

[greenkat]

Promising-looking hot tower in the middle of Isaac.

[WeatherGuesser]

8:00 PM EDT Sat Aug 25
Location: 21.7°N 76.7°W
Moving: NW at 20 mph
Min pressure: 997 mb
Max sustained: 60 mph

[OzCycloneChaserTrav]

Anyone who doesn't evacuate along parts of the coast that are prone to storm surges, in Florida, Alabama or wherever Isaac decides to affect, has rocks in there head.

[SFLcane]

Storms trying to wrap around llc..

[ozonepete]

Still nw

Yup. And pulling quickly away from the mountains on eastern Cuba.

[BigEasy]

Still nw

Why is still nw, funny? I don't understand.

[cheezyWXguy]

Look at the overall structure of Isaac. The "tail" is sucking in from the south to the SW and the NE part of the envelope is tightening up as well. This large system is quickly coming together. Much different from any system I've seen that has gone through Haiti and Cuba in the past 20 years. He could be formidable in the next day or two, RI is not out of the question IMHO.

The posts 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.org. For official information, please refer to the NHC and NWS products.

I agree, this one is unique that's for sure. It doesnt seem common that a llc can maintain so well in the absence of convection, and this has really allowed us to observe the changes in low level structure of an organizing system, a process usually blocked out of our view by abundant convection. And at that, watching that llc tighten up so well today, it really does seem that Isaac could strengthen quickly once it pulls away a bit more.

[jinftl]

Note that Isaac is 375 miles ese of Key West...if he continues on a more or less a NW heading, that would seem to suggest a track that will be east of Key West (or near, since wobbles happen here and there)...or through the lower-middle-upper FL Keys

SUMMARY OF 800 PM EDT...0000 UTC...INFORMATION
----------------------------------------------
LOCATION...21.7N 76.7W
ABOUT 80 MI...130 KM ENE OF CAMAGUEY CUBA
ABOUT 375 MI...605 KM ESE OF KEY WEST FLORIDA
MAXIMUM SUSTAINED WINDS...60 MPH...95 KM/H
PRESENT MOVEMENT...NW OR 310 DEGREES AT 20 MPH...31 KM/H
MINIMUM CENTRAL PRESSURE...997 MB...29.44 INCHES

[BigEasy]

Isaac remains unorganized as I see it, but when he enters the GOM, the overall cloud pattern and circulation will take up a very large portion of the Gulf. Isaac has a huge circulation pattern.


The posts 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.org. For official information, please refer to the NHC and NWS products.

[tgenius]

At this point any northern component brings worse weather for Miami. I'm intrigued that Isaac can still keep on chugging along despite the numerous adversities that he has faced.

[Cyclenall]

I'm amazed it was able to hold on to 50 knots and sub-1000 mb pressure during its passage, well done Issac! It beat the odds and didn't weaken very much. Now it can quickly organize in the extreme warm waters off the northern coast of Cuba and once its southern inflow is no longer cut off as much, maybe RI can start. Current satellite imagery shows it is already sort of taking off with that bursting convection which may be a sign it will be strengthening faster than what the NHC has forecasted in the very near term. The main concern waking up to this thing was its large size...while that and its faster movement helped it through its passage of land, its needs to transform into a smaller TC and slow down a bit for optimal results.

ISAAC IS CURRENTLY PART OF A
LARGE LOW/MID-LEVEL LOW PRESSURE SYSTEM COVERING THE NORTHWESTERN
CARIBBEAN SEA AND THE ADJACENT LAND AND OCEAN AREAS. THIS LOW
PRESSURE AREA HAS A SECOND VORTICITY CENTER BETWEEN JAMAICA AND THE
CAYMAN ISLANDS...AND FOR THE NEXT 24-36 HR ISAAC AND THIS CENTER
WILL LIKELY ROTATE AROUND EACH OTHER. BASED ON THIS EXPECTATION...
THE FORECAST TRACK SHOWS ISAAC MOVING NORTHWESTWARD FOR 12 HR OR
SO...FOLLOWED BY A TURN TOWARD THE WEST-NORTHWEST.

This is crazy, a possible mini Fujiwara interaction with a low near the Caymans? Such a odd scenario and fun one. Extremely interesting.

A COMBINATION OF LIGHT WESTERLY VERTICAL WIND SHEAR AND LAND
INTERACTION SHOULD AT LEAST SLOW INTENSIFICATION FOR THE NEXT 12
HR.

*******

INIT 25/2100Z 21.3N 76.0W 50 KT 60 MPH
12H 26/0600Z 22.6N 78.0W 55 KT 65 MPH
24H 26/1800Z 24.1N 80.6W 60 KT 70 MPH

This part may be overdoing the slow intensification part, based on how well organized it has remained compared to expectations, I would not be surprised if its 55 knots by 11:00 pm and 60 knots by 5:00 am. Why does a 5 knot difference matter here? I think the sooner it builds its inner core back to shape the more likely RI can occur when in the Florida Straits. 5-10 knots might make a big difference here and follow an exponential curve. The NHC forecast has been fantastic though in the last 18-24 hours however.

IT SHOULD BE NOTED THAT THE GLOBAL MODELS ARE
FORECASTING A VERY FAVORABLE PATTERN OF UPPER-LEVEL WINDS OVER THE
NORTHERN GULF OF MEXICO BY 72 HR. SHOULD THIS VERIFY AND SHOULD
ISAAC ESTABLISH AN INNER CORE...THE CYCLONE COULD BE SIGNIFICANTLY
STRONGER THAN CURRENTLY FORECAST.

This is the 2nd time the NHC has stated this, another ominous sign for the northern Gulf coast. They can already smell the huge end to the 7 year streak.

[ozonepete]

Still nw

Why is still nw, funny? I don't understand.

That's a smile, not a laugh. We all smile when the forecast verifies what we've been seeing.

[BigEasy]

Still nw

Why is still nw, funny? I don't understand.

That's a smile, not a laugh. We all smile when the forecast verifies what we've been seeing.

Oh, I get it. Thanks!

[SFLcane]

Note that Isaac is 375 miles ese of Key West...if he continues on a more or less a NW heading, that would seem to suggest a track that will be east of Key West (or near, since wobbles happen here and there)...or through the lower-middle-upper FL Keys

SUMMARY OF 800 PM EDT...0000 UTC...INFORMATION
----------------------------------------------
LOCATION...21.7N 76.7W
ABOUT 80 MI...130 KM ENE OF CAMAGUEY CUBA
ABOUT 375 MI...605 KM ESE OF KEY WEST FLORIDA
MAXIMUM SUSTAINED WINDS...60 MPH...95 KM/H
PRESENT MOVEMENT...NW OR 310 DEGREES AT 20 MPH...31 KM/H
MINIMUM CENTRAL PRESSURE...997 MB...29.44 INCHES

18z GFDL brings it towards upper keys..

[meriland23]

fujiwara? Isn't that what Ike did?

[cheezyWXguy]

Isaac remains unorganized as I see it, but when he enters the GOM, the overall cloud pattern and circulation will take up a very large portion of the Gulf. Isaac has a huge circulation pattern.


The posts 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.org. For official information, please refer to the NHC and NWS products.

In terms of convection, there's not much there to be organized atm, but it certainly has a well formed LLC and apparently a pretty strong MLC as well. Now that its putting distance between it and the coast, the entire northern half of the core has lit up with deep convection. We will likely be waking up to a very different system tomorrow than we are looking at currently.

[ozonepete]

I'm amazed it was able to hold on to 50 knots and sub-1000 mb pressure during its passage, well done Issac! It beat the odds and didn't weaken very much.
This is crazy, a possible mini Fujiwara interaction with a low near the Caymans? Such a odd scenario and fun one. Extremely interesting.

I think the low shear and most of all the extremely impressive outflow are what kept it from weakening or disorganizing more.

As for the "mini-Fuji", lol, that IS really fascinating. Looks to me like that's what jogged it more northerly to a NW movement. IMHO looks like the small low near Isle of Pines/Caymans is already weakening a lot and the Fujiwara effect is waning. But that still doesn't tell us how long Isaac will remain on an NW course. Could hold onto that heading for a while just based on momentum.