ATL: ISAIAS - Post-Tropical - Discussion

[Shell Mound]

Since the GFS and Euro have been so bad with the development of Gonzalo and Hanna, and those issues definitely won’t magically correct themselves for 92L just days afterwards, it’s probably likely that the actual future of 92L will be very different. Two broad possibilities seem the most plausible:

1.) the complete opposite of Gonzalo and Hanna happens — 92L fails to develop despite strong model support and either rams into the Greater Antilles or becomes Gonzalo 2.0, gulping SAL and limping its way to its deathbed.

2.) 92L exceeds expectations and becomes a stronger system than any of the models were anticipating, either on the same track they’re now showing or on a Caribbean Cruiser track.

Given the conservative bias of the EPS/ECMWF and the G(E)FS thus far, option two seems far more plausible than option one at this stage.

To be fair, however, you shouldn’t necessarily say “any of the models.” The UKMET and CMC have been fairly bullish with 92L/Isaias.

[DestinHurricane]

Here's what i'm thinking this far out, though i'm no pro met.

50% - only affects islands. No CONUS landfall
15% - Landfall or scrapes the NE
15% - North Carolina
10% - Northeast FL to S Carolina
5% FL south of cape Canaveral
5% Gulf

[gatorcane]

92l continues to look more disorganized as SAL and the fast forward speed take its toll. Wouldn’t be surprised if models start becoming more bearish on this but of course at some point down the road, it could find more favorable conditions so we watch and wait:

[aspen]

Since the GFS and Euro have been so bad with the development of Gonzalo and Hanna, and those issues definitely won’t magically correct themselves for 92L just days afterwards, it’s probably likely that the actual future of 92L will be very different. Two broad possibilities seem the most plausible:

1.) the complete opposite of Gonzalo and Hanna happens — 92L fails to develop despite strong model support and either rams into the Greater Antilles or becomes Gonzalo 2.0, gulping SAL and limping its way to its deathbed.

2.) 92L exceeds expectations and becomes a stronger system than any of the models were anticipating, either on the same track they’re now showing or on a Caribbean Cruiser track.

Given the conservative bias of the EPS/ECMWF and the G(E)FS thus far, option two seems far more plausible than option one at this stage.

To be fair, however, you shouldn’t necessarily say “any of the models.” The UKMET and CMC have been fairly bullish with 92L/Isaias.

What I mean by “more I tense than any of the models are showing” is 92L/Isaias finding a sweet spot to bomb out into a Cat 4 (conditions are not good enough for a Cat 5 at this time). The strongest models so far show a Cat 2/3.

[SFLcane]

Wow 70-90% now!


A broad area of low pressure located over the central tropical Atlantic continues to produce a wide area of disorganized showers and thunderstorms as it moves westward around 20 mph. Environmental conditions are forecast to be conducive for development and a
tropical depression or tropical storm is likely to form within the
next two or three days as the system nears the Lesser Antilles.
Interests in the Lesser Antilles should monitor the progress of this
system.
* Formation chance through 48 hours...high...70 percent.
* Formation chance through 5 days...high...90 percent.

$$

[HurricaneAndre2008]

412
ABNT20 KNHC 261714
TWOAT

Tropical Weather Outlook
NWS National Hurricane Center Miami FL
200 PM EDT Sun Jul 26 2020

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

The National Hurricane Center is issuing advisories on Tropical
Storm Hanna, located inland over northeast Mexico.

A broad area of low pressure located over the central tropical
Atlantic continues to produce a wide area of disorganized showers
and thunderstorms as it moves westward around 20 mph. Environmental
conditions are forecast to be conducive for development and a
tropical depression or tropical storm is likely to form within the
next two or three days as the system nears the Lesser Antilles.
Interests in the Lesser Antilles should monitor the progress of this
system.
* Formation chance through 48 hours...high...70 percent.
* Formation chance through 5 days...high...90 percent.

$$
Forecaster Zelinsky

[TheStormExpert]

I mean a Tropical Depression or Storm is likely to form but a hurricane might be a long shot just going off the current 12z model suite.

[abajan]

92l continues to look more disorganized as SAL and the fast forward speed take its toll. Wouldn’t be surprised if models start becoming more bearish on this but of course at some point down the road, it could find more favorable conditions so we watch and wait:

https://i.postimg.cc/HsdbBwyS/goes16-vis-92-L-202007261405-lat11-5-lon323-1.jpg

Looks like at least one of the centers of circulation is visible in that image: near 10.7N 37.0W. But I don't know whether it's a low level one or not.

[toad strangler]

92l continues to look more disorganized as SAL and the fast forward speed take its toll. Wouldn’t be surprised if models start becoming more bearish on this but of course at some point down the road, it could find more favorable conditions so we watch and wait:

https://i.postimg.cc/HsdbBwyS/goes16-vis-92-L-202007261405-lat11-5-lon323-1.jpg

Disagree, that's a healthy juicy wave waiting for a spark. Look at the rotation.
http://www.tropicaltidbits.com/sat/satlooper.php?region=92L&product=truecolor

[chaser1]

92l continues to look more disorganized as SAL and the fast forward speed take its toll. Wouldn’t be surprised if models start becoming more bearish on this but of course at some point down the road, it could find more favorable conditions so we watch and wait:

https://i.postimg.cc/HsdbBwyS/goes16-vis-92-L-202007261405-lat11-5-lon323-1.jpg

Looks like at least one of the centers of circulation is visible in that image: near 10.7N 37.0W. But I don't know whether it's a low level one or not.

You're seeing that correctly though that low level swirl will spin itself out just as the one previous to it did. Appears that another LLC might be attempting to be the dominant around 11N and 39W. What appears to be occurring is that the large mid level circulation is chugging off to the west at a pretty good clip leaving any low level center attempting to stack underneath, to spin out from under the overall envelope due to difficulty to maintain any consistent convection and surface pressure drop to allow a vertical structure to better develop. Dryer air due to SAL is probably a contributing factor however it would appear that NHC anticipates those conditions to soon improve significantly. My concern is that the further west 92L tracks prior to developing, the greater the threat to the Lesser & Greater Antilles and potentially points west thereafter.

[wxman57]

I don't expect it to do much for the next couple of days due to its very fast west movement. Should be a TD by Wednesday and a TS as it enters the NE Caribbean Wednesday night. Near the Bahamas next Fri/Sat, quite possibly as a hurricane. Beyond then, who knows? Models indicate a trof off the East U.S. Coast next weekend. If it's stronger, it could be steered north, missing the US to the east. For now, I'd put my money on a Carolinas hit early next week. Way too far out and very low confidence on that forecast, though. I think if it's slower to develop and is weaker, then a more westerly track, which could take it to the NW Caribbean in 7-8 days.

[chaser1]

92l continues to look more disorganized as SAL and the fast forward speed take its toll. Wouldn’t be surprised if models start becoming more bearish on this but of course at some point down the road, it could find more favorable conditions so we watch and wait:

https://i.postimg.cc/HsdbBwyS/goes16-vis-92-L-202007261405-lat11-5-lon323-1.jpg

Disagree, that's a healthy juicy wave waiting for a spark. Look at the rotation.
http://www.tropicaltidbits.com/sat/satlooper.php?region=92L&product=truecolor

Can't argue with what the eyes can plainly see however this season has shown us that "road-kill" will essentially spin up in the Atlantic if given the right opportunity and set of conditions. I think this is just too pronounced of a system for it to fully degenerate and never develop. I have to think that it's more a matter of "when and where" then "if".

[jlauderdal]

I don't expect it to do much for the next couple of days due to its very fast west movement. Should be a TD by Wednesday and a TS as it enters the NE Caribbean Wednesday night. Near the Bahamas next Fri/Sat, quite possibly as a hurricane. Beyond then, who knows? Models indicate a trof off the East U.S. Coast next weekend. If it's stronger, it could be steered north, missing the US to the east. For now, I'd put my money on a Carolinas hit early next week. Way too far out and very low confidence on that forecast, though. I think if it's slower to develop and is weaker, then a more westerly track, which could take it to the NW Caribbean in 7-8 days.

You make far too much sense for this board...im with you on the development schedule... I do think it gets farther the west than some of the experts on the model thread have it going

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[HurricaneAndre2008]

They are writing off 92L on wunderground. Lol

[chaser1]

I don't expect it to do much for the next couple of days due to its very fast west movement. Should be a TD by Wednesday and a TS as it enters the NE Caribbean Wednesday night. Near the Bahamas next Fri/Sat, quite possibly as a hurricane. Beyond then, who knows? Models indicate a trof off the East U.S. Coast next weekend. If it's stronger, it could be steered north, missing the US to the east. For now, I'd put my money on a Carolinas hit early next week. Way too far out and very low confidence on that forecast, though. I think if it's slower to develop and is weaker, then a more westerly track, which could take it to the NW Caribbean in 7-8 days.

You make far too much sense for this board...im with you on the development schedule... I do think it gets farther the west than some of the experts on the model thread have it going

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Couldn't agree more. There's a reason why Hanna did not recurve toward the mid Atlantic. There was no coherent mid level feature (let alone organized tropical cyclone) to pull north LOL. That's what allowed what was little more then a vigorous TW to track west and dump copious amounts of heavy tropical rains over S. Florida, reach the GOM and eventually develop within a region conducive for development. I assume 92L could rapidly coalesce into a tropical depression and the resulting track motion would probably be similar to those that models presently project. Now, assume that the far more likely event suggesting that a T.S. might not develop for at least 36 hours, or even later until approaching the Islands or Puerto Rico. This potentially changes things up quite a bit. One could continue to push similar scenarios even further west and eventually that landfall threat theoretically takes you as far west as the GOM again. I doubt that will occur but the point being that modeling play's an important role when accurate initialization exists. For the moment 92L is a broad behemoth with no organized convection, CDO, banding, or defined closed surface wind field. We just have to patiently wait and watch for a couple days.

[cycloneye]

18z Best Track:

92L INVEST 200726 1800 11.8N 38.5W ATL 25 1010

[BYG Jacob]

I don't expect it to do much for the next couple of days due to its very fast west movement. Should be a TD by Wednesday and a TS as it enters the NE Caribbean Wednesday night. Near the Bahamas next Fri/Sat, quite possibly as a hurricane. Beyond then, who knows? Models indicate a trof off the East U.S. Coast next weekend. If it's stronger, it could be steered north, missing the US to the east. For now, I'd put my money on a Carolinas hit early next week. Way too far out and very low confidence on that forecast, though. I think if it's slower to develop and is weaker, then a more westerly track, which could take it to the NW Caribbean in 7-8 days.

I certainly hope not, the GoM and Caribbean are boiling, and that would be over ridiculous OHC

[MGC]

92L looks to have a large circulation. Will take a while to get going. GFS is spinning it up and deepening it too quickly I think. Might be a threat to the northern islands......MGC

[northjaxpro]

They are writing off 92L on wunderground. Lol

Very foolish if they are actually doing that.

[BYG Jacob]

They are writing off 92L on wunderground. Lol

This happens every year. This is why you shouldn't just hug models or climo, Storms have a habit of making people who do so look very silly