ATL: ISAIAS - Post-Tropical - Discussion

[ScottNAtlanta]

https://media.discordapp.net/attachments/289981599448039425/737666568183349260/LATEST.png?width=677&height=677
SW side clearly dominant

But still looks elongated.

Looking at the ASCAT above, the western lobe is pinching off

[plasticup]

Saved loop. Looks to be big and gradually organizing while moving quickly. Still a lot of SAL around it:

https://i.postimg.cc/zBKtGCng/BC63-A42-C-B225-4-BFF-BDC6-EA1-A8-D1-B0-F48.gif

Nice image. The circulation on this system is a bit larger than Gonzalo, no?

Just a little

[Nancy Smar]

AL092020 - Tropical Storm INVEST

https://rammb-data.cira.colostate.edu/tc_realtime/storm.asp?storm_identifier=al092020

[St0rmTh0r]

Looks like the sw area people were talking about yesterday is starting to take over big changes to track coming if this happens

[wxman57]

I don't understand why NHC isn't issuing advisories for a Potential Tropical Cyclone. The Antilles are within range of watches/warnings. My guess is the NHC is waiting until they feel more confident where a center will consolidate. Possibly after the recon flight today, if recon doesn't find a TC already.

I sure wish I had the option of not issuing an advisory until I was more confident where a potential storm will track. We started issuing 7-day forecasts on Sunday for this disturbance. I'm quite confident in it tracking across the NE Caribbean Wed/Thu as a 35-40 kt TS. Beyond then, who knows? Consensus takes it near SE FL on Sunday as a very slow-moving storm. EC and GFS take it into south Florida as a depression on Sunday then dissipate it inland. GFS is indicating a big battle with dry air after exiting the NE Caribbean on Thursday, leading to its demise as it nears Florida. A small percentage of the GFS and Euro ensemble members indicate a track toward the Carolinas, but most EC members either dissipate it in a few days or have it reaching south Florida as a depression. Only about 8 of the 51 members take it to the Carolinas as a TS or H. The "new" GFS makes it a major hurricane into the Carolinas on Monday night. It remains to be seen how much we can trust this updated version of the GFS. Perhaps the recon data will help tonight's models? Would help if they sent out a G-IV to sample the atmosphere in its path.

[AubreyStorm]

AL092020 - Tropical Storm INVEST

https://rammb-data.cira.colostate.edu/tc_realtime/storm.asp?storm_identifier=al092020

Hmmmmmmm? At 11am TD?

[USTropics]

Upper-level consolidation over the past 24 hours really tells the story:


I agree with Aric, the eastern vorticity will begin to become stretched out from west to east soon. You can see this happening in the mid-levels now:

[Nancy Smar]

AL092020 - Tropical Storm INVEST

https://rammb-data.cira.colostate.edu/tc_realtime/storm.asp?storm_identifier=al092020

Hmmmmmmm? At 11am TD?

Probably Potential Tropical Cyclone Nine.

[Kazmit]

AL092020 - Tropical Storm INVEST

https://rammb-data.cira.colostate.edu/tc_realtime/storm.asp?storm_identifier=al092020

Hmmmmmmm? At 11am TD?

It already has TS winds. Probably a PTC.

[Nancy Smar]

AL, 09, 2020072812, , BEST, 0, 135N, 528W, 35, 1007, DB, 34, NEQ, 200, 0, 0, 120, 1012, 300, 150, 0, 0, L, 0, , 0, 0, NINE, S, 0, , 0, 0, 0, 0, genesis-num, 021, TRANSITIONED, alB22020 to al092020,

[ouragans]

TD with TS winds? That's weird....

[TheStormExpert]

First Potential Tropical Cyclone advisory coming at 11am it looks in don’t remember how long.

[Mialco]

Considering that the leading cloud mass is practically on our doorstep here in Barbados, I imagine that at least PTC advisories should be initiated in the next update. By the time the hurricane hunter gets into it, we might already be seeing an increase in deteriorating conditions
#watchingclosely

[Nancy Smar]

Special Message from NHC Issued 28 Jul 2020 14:25 UTC
NHC will initiate advisories on Potential Tropical Cyclone Nine, located about 400 miles east of the Windward Islands, at 11 am AST.

[TheStormExpert]

TD with TS winds? That's weird....

This likely means if and when it gets better organized it’ll likely be upgraded directly to TS.

[ouragans]

TD with TS winds? That's weird....

This likely means if and when it gets better organized it’ll likely be upgraded directly to TS.

I just saw they will upgrade to PTC. Logic, but this should have been done at 9z

[Florida1118]

TD with TS winds? That's weird....

This likely means if and when it gets better organized it’ll likely be upgraded directly to TS.

"Probably time to put this Invest to rest"

[Dean4Storms]

That western portion of the wave sure looks suspicious on satellite and if it goes on to develop this is a Carib. Sea runner IMO.

[Shell Mound]

Based on the latest visible imagery, the southwestern lobe clearly seems to be taking over. Low-level rotation near the northeastern lobe is weakening and veering, while low-level rotation is backing and strengthening near the southwestern lobe, so for the first time the circulation seems to be becoming a bit more symmetrical on balance. A wide-angle view seems to confirm this new, gradual trend. A future LLC seems increasingly likely to consolidate in the vicinity of the southwestern lobe. Additionally, inflow seems to be strengthening in this area, based on the movement of the low-level clouds.

[Hurricaneman]

My forecast for this

Track hasn’t changed since my last forecast except a second US landfall near St Marks Fl and a wee bit slower

Intensity I’m inching up a bit in the long term

Now. PTC. 40mph
12hrs. TS. 45mph
24hrs. TS. 50mph
36hrs. TS. 65mph
48hrs. TS. 65mph
72hrs. TS. 60mph
96hrs. TS. 60mph
120hrs. TS. 70mph
144hrs. C1. 80mph off Palm Beach