ATL: ISAIAS - Post-Tropical - Discussion

[NDG]

If the system indeed takes the persistent track that the Euro has been forecasting run after run, north of Cuba, whoever thinks is going to have SW shear to deal with is lying to themselves. With the trough axis all the way west over the MS river valley it should have fairly good UL conditions.
Remember how bad they were with the intensity of Hanna 2-3 days before making landfall.

Any idea or guess on where PTC-9 may end up or go with that trough?

It all depends what kind of a shape it is after leaves Hispaniola and if the narrow ridge to the north weakens or stays strong, tomorrow we should have a better idea of its tracks, just east of FL, over FL or along the west coast of FL.

[StormPyrate]

Isn't this pretty much a situation that the Hunters were built for?
When does the next one go in? Or is it just not warranted right now

[jconsor]

 https://twitter.com/yconsor/status/1288568069804232704

[Hammy]

Might actually be closing off, at least at cloud level--on NASA's N America view, go directly south of Puerto Rico to the bottom of the map and loop it.

[northjaxpro]

If the system indeed takes the persistent track that the Euro has been forecasting run after run, north of Cuba, whoever thinks is going to have SW shear to deal with is lying to themselves. With the trough axis all the way west over the MS river valley it should have fairly good UL conditions.
Remember how bad they were with the intensity of Hanna 2-3 days before making landfall.

Any idea or guess on where PTC-9 may end up or go with that trough?

It all depends what kind of a shape it is after leaves Hispaniola and if the narrow ridge to the north weakens or stays strong, tomorrow we should have a better idea of its tracks, just east of FL, over FL or along the west coast of FL.

I am going to stick my neck out here. I have done this with decent success I may add. It is not the first time I have done this through the years for sure. NDG, I will say that the narrow ridge will lbe there. We will know soon.

[Blown Away]

DATE TIME LAT LON CLASSIFICATION ID NAME
20200729 1730 16.1 64.6 T2.5/2.5 09L NONAME
20200729 1130 15.5 62.4 T2.5/2.5 09L NONAME
20200729 0530 14.5 59.4 T2.0/2.0 09L NONAME
20200728 2330 14.7 56.7 T1.5/1.5 09L NONAME

Been gaining latitude all day...

[Javlin]

So we have Team West
NorthJaxPro
Aric
and Myself

From this morning so I am in also

Postby Javlin » Wed Jul 29, 2020 8:47 am
Looking at MIMIC this one rolls W for while and either impacts CA or the trough over the US lifts it some?This has been the main steering for the last month.

http://tropic.ssec.wisc.edu/real-time/m ... anim=html5

[skillz305]

Well, safe to say nobody in Central Florida is preparing for anything. This is still 24 hours too far out for us to really even take it serious. Those in FL know the windshield wipers help us panic at the last moment almost when it's too late. But safe to say, this storm having trouble organizing is a blessing as of now. Nobody knows were this is headed, we just know that it'll be on the low end of the scale (hopefully).

[xironman]

Looks like it is developing way SW, may be wide left on Hispaniola and closer to Cuba

[wx98]

Still a PTC, no Isaias yet...

SUMMARY OF 500 PM AST...2100 UTC...INFORMATION
----------------------------------------------
LOCATION...16.4N 65.6W
ABOUT 105 MI...170 KM SSW OF ST. CROIX
ABOUT 320 MI...510 KM ESE OF SANTO DOMINGO DOMINICAN REPUBLIC
MAXIMUM SUSTAINED WINDS...45 MPH...75 KM/H
PRESENT MOVEMENT...WNW OR 290 DEGREES AT 23 MPH...37 KM/H
MINIMUM CENTRAL PRESSURE...1004 MB...29.65 INCHES

[jaxfladude]

So more or less of the likelihood of this being an unnamed system throughout any if at all Florida impacts like in the islands in the Caribbean? Mostly heavy rains and strong winds? How bad will the islands be impacted and which ones are likely to hardest hit/impacted?

[caneseddy]

Key points from discussion

More recently, a band has
developed over the southwestern portion of the broad circulation
and it appears that the system may be closer to acquiring a
well-defined center

Since the system still lacks a
well-defined center it is not surprising to see these
inconsistencies in the model runs. As a result, the NHC forecast
has been shifted eastward, but it remains to the west of the latest
multi-model consensus aids out of respect for continuity and the
continued possibility of further model shifts.

As mentioned
above, some of the global models are now showing a track farther
away from eastern Cuba and east of Florida, and if that occurs the
NHC intensity forecast could be somewhat conservative. Interests
in the Bahamas, Cuba, and Florida should continue to monitor
forecasts as changes to both the track and intensity are likely.

[Evil Jeremy]

Discussion highlights:

"a band has developed over the southwestern portion of the broad circulation
and it appears that the system may be closer to acquiring a
well-defined center"

"the NHC forecast has been shifted eastward, but it remains to the west of the latest
multi-model consensus aids out of respect for continuity and the
continued possibility of further model shifts"

"The system is likely to take some
time to recover after its passage over land, and given the forecast
for at least moderate south to southwesterly shear, only
gradual strengthening is indicated at that time. As mentioned
above, some of the global models are now showing a track farther
away from eastern Cuba and east of Florida, and if that occurs the
NHC intensity forecast could be somewhat conservative."

[caneseddy]

[aspen]

If the new NHC cone verifies, PTC-9/Isaias will have 18-24 hours over warm (29-30 C) waters before making landfall in southern Florida. However, the degree of windshield wiping with the models and official forecast cone, along with the high uncertainty in the exact location of the center of the system, make it unlikely that Isaias’ actual track will be like this.

Either side of Florida has its ups and downs for future Isaias. To the east, it could take advantage of the extremely high Gulf Stream SSTs, but it would have to fight against a trough imparting shear on it. To the west, Isaias could avoid the trough (from what I’ve heard), but the waters in the eastern Gulf, while warm, are quite shallow and recently disturbed.

[CaribJam]

Can a pro explain this extract from the discussion for me, please:
More recently, a band has
developed over the southwestern portion of the broad circulation
and it appears that the system may be closer to acquiring a
well-defined center

Are they hinting/suggesting that the "centre" may be forming to the southwest? And what influence will this have on the short-term movement of the system, especially for us in the Central Caribbean?
Thanks

[SFLcane]

Should be named before the 11pm advisory.

[CourierPR]

I wonder if this will take a path similar to Hurricane Cleo in 1964, which crossed the mountains of eastern Cuba and then continued up the Florida east coast.

[psyclone]

If the new NHC cone verifies, PTC-9/Isaias will have 18-24 hours over warm (29-30 C) waters before making landfall in southern Florida. However, the degree of windshield wiping with the models and official forecast cone, along with the high uncertainty in the exact location of the center of the system, make it unlikely that Isaias’ actual track will be like this.

Either side of Florida has its ups and downs for future Isaias. To the east, it could take advantage of the extremely high Gulf Stream SSTs, but it would have to fight against a trough imparting shear on it. To the west, Isaias could avoid the trough (from what I’ve heard), but the waters in the eastern Gulf, while warm, are quite shallow and recently disturbed.

They are shallow...and less warm compared to a couple weeks ago...but they are plenty warm for a transiting storm. every bit as warm if not warmer than the shelf waters that enabled Michael to attain cat 5 status on approach to the panhandle in 2018.. mid to upper 80's. If the system struggles it won't be for lack of warm water around florida.

[supercane4867]