ATL: ISAIAS - Post-Tropical - Discussion

[ConvergenceZone]

Edit: wunderground was showing winds down to 75mph, but it looks like an error, as they seemed to have fixed it now

[galaxy401]

Wasn't it up to 80 mph earlier? if so, down to 75 mph now.....Perhaps the weakening trend is starting earlier than anticipated. Getting hammered with dry air and shear...

Uhh they actually upped it to 85 mph. Little stronger apparently.

[ConvergenceZone]

Wasn't it up to 80 mph earlier? if so, down to 75 mph now.....Perhaps the weakening trend is starting earlier than anticipated. Getting hammered with dry air and shear...

Uhh they actually upped it to 85 mph. Little stronger apparently.

yes, I edited my post. Apparently it was a typo on Wunderground Site. They fixed it now.....
Although looking at the forecast for wind speeds tomorrow, the strength appears to have come close to peaking. , so doesn't look like they are expecting much strengthening from here on out, just slowly leveling off and then a gradual decrease in wind speed.
I wouldn't be surprised though if this gets up to 90 mph in the morning though.

[Airboy]

The convection looked a bit beaten last couple of hours but have built up again last hour or so.

[Highteeld]

Not looking great this morning. CDO has really shrunk.

[CFLHurricane]

Not looking great this morning. CDO has really shrunk.

Isaias is quite anemic- I wonder if he’ll even survive today?

[GCANE]

The big infeed from the EPAC got disrupted by Hispaniola.
Looks like it'll clear the island soon and get back over open water.
A big surge of moisture from the EPAC has already entered the Carib.
Need to watch how this pool of high TPW air moves closer to Isaias.
A second infeed is also seen over east Cuba.

Timing down the road later today will be interesting.
Convection over Cuba needs to fire up and feed the mid-layers.
There wasn't much of it yesterday afternoon which explains the east blob and drop in the eyewall structure.

Yesterday, the GIV survey showed very dry air ahead at 500mb and above.
NOAA 9 is back up again and currently flying at 45000 ft.

There currently is a strong inflow of 3500 CAPE air is being entrained into the core.
It looks to be digging deeper into the southern flank of the core and cutting off the dry air entrainment.

Hot towers will keep this alive as long as pressure can continue to drop which in turn will increase it's infeeds.
This will help counter the effects of the UL Jet created by the Rossby Wave to its NW.
I expect more pulsing behavior in the next 24 hrs.

I'll check into what happens on approach to FL in a bit.
Diurnal timing is critical.
A lot depends on CAPE and if convection fires over FL which would moisten the mid and upper part of the troposphere.
I know there is typically a large high-CAPE pool that persistently sits off the east coast of FL and extends into the NW Bahamas due to the hot water coming out of the GoM and flowing along the east coast of FL aka the Gulf Stream.

[GCANE]

For this time of day, the Gulf Stream is already juiced, 3500 to 4500 CAPE!
It'll get higher during the day as the sun lifts moisture off the ocean surface.
Also, as Isaias gets closer WISHE will also push moisture into the boundary layer of the atmosphere.
Diurnal timing maybe be somewhat more minimal that I first thought.

[GCANE]

That Rossby Wave is a lot farther west and weaker than I thought it would be a couple days ago.
Looks like it may be able to battle the UL Jet better.
Also has implications on the trough and track.

[GCANE]

Holy crap, that was quick, 5000 CAPE in the Gulf Stream!
Buckle up if the mid-layers get moistened.

[GCANE]

Damn, latest from NOAA 9.
The mid-layer is getting moistened.
Big difference from last night.
Probably wont get into the models for some time.

[otowntiger]

Not looking great this morning. CDO has really shrunk.

Agreed. Definitely looking tiny and unimposing. And I’m sticking to my guns- it looks like it will not make FL landfall. So it’s potentially good news on two fronts- shrinking/ weakening storm that stays further away. The NHC does a great job with the track forecasting- and I think they will have called it right here again.

[N2FSU]

5am NHC track



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[chaser1]

Damn, latest from NOAA 9.
The mid-layer is getting moistened.
Big difference from last night.
Probably wont get into the models for some time.

https://i.imgur.com/WMM771f.png

I'm not to sure it'll make it into Isaias either

[GCANE]

IMHO, a lot farther west from the forecast track.
Need recon to verify.
Winds starting to pile up on the east coast.
Could get a big burst of convection soon.

Need to see where we're at when it gets on the other side of Andros.

[SouthernBreeze]

Almost appears to be heading west in last few satellite frames

[Hurricane Mike]

Morning video update on Isaias
https://www.youtube.com/watch?v=f9ncEZb_XSc

[AdamFirst]

IMHO, a lot farther west from the forecast track.
Need recon to verify.
Winds starting to pile up on the east coast.
Could get a big burst of convection soon.

Bahamian radar looks like its going to split Andros down the middle, SE to NW. Dont think this skirts around it

[GCANE]

WV imagery showing mid-level dry air entrainment being cutoff on the SE flank of the CoC.
Radar showing convection reappearing and maybe attempting to rebuild the southern eyewall.
Looks like it may be more on track now.

[Nimbus]

Shear is obviously limiting development but with the track staying off the east coast of Florida and less shear as it tracks over the gulf stream we need to be concerned with watches and warnings for landfall in NC. Looks like official track takes it near Wilmington without a recurve.