ATL: IDALIA - Post-Tropical - Discussion

[cycloneye]

This will be the plane that has departed that will feed bigtime the models as it is Gonzo that is the high altitude plane that collects data from the upper atmosphere.

[chaser1]

With the 12z GFS, i would expect a slight... west nudging of the cone

newest run was east of the previous run, wasn't it? and the 11AM discussion said their path may need to move further east

correct; I thought i had read that even with NHC's eastward nudge, it still remained a bit west of the TVCN. Of course, NHC doesn't like to whip forecast track around from update to update simply based on any one single model run thus we may see little change in forecast track in spite of some 18Z models leaning more to the right (given newly ingested recon data, better initialization, etc). My guess is that 0Z model runs might reconfirm a slight eastward trend in track and therefore might see NHC begin nudging landfall a tad earlier and a bit further south (and east).

[TallyTracker]

The eastern rainband just spit out a massive outflow boundary and is collapsing. That should allow more inflow from the eastern side of the storm. I expect full convective coverage over the center in the coming few hours.

[BobHarlem]

With the 12z GFS, i would expect a slight... west nudging of the cone

Yeah they did shift west but with a stronger storm overall. Does anybody know if the 12z runs have the latest dropsonde data? Or is that going in the 18 runs.

18z should have the first recon data, 0z will have a lot more of it (including the high altitude stuff)

[FLpanhandle91]

That constant convection firing just south of the COC is very impressive for mid-day with relatively modest CAPE. I believe this is the start of the CDO for Idalia. If some of that convection can rotate upshear, it's wheels up IMO.

[Ian2401]

Looks completely stationary. Our in house track fixes at my work had a northward component earlier when recon was sampling it, but it seems to be completely stationary now. Although hard to tell based on just sat imagery especially now that the naked swirl is mostly covered up

[BobHarlem]

First Hurricane/Surge watches for Florida likely at 5pm or no later than 11pm.

Interests in Florida should monitor the progress of this system.
Storm surge and hurricane watches for portions of the Florida west
coast will likely be required later today.

[shannalynn35]

With the 12z GFS, i would expect a slight... west nudging of the cone

Doubt they change the track much if at all at 5pm. 12z GFS init point was about 60 miles wnw of where recon actually pegged it. 18z and especially 0z runs with recon data may be a bit better, but GFS has had a historically west bias in this area. Even so the 12z GFS shifted slightly right from 6z (From around Apalachicola to about St. Marks).

If I was along anywhere from Sarasota north into PCB that could be impacted by surge I wouldn't mess around.

I am in Bradenton just north of Sarasota so I am watching very carefully!

[ronjon]

Looks that mid-level ridging will be building over S FL the next few days as Franklin departs. Most models are showing a solid northward movement up to the latitude of Tampa or slightly north of there. This should prevent an Ian like track scenario. Pretty good consensus of CMC, Ukmet, GFS, NAM, and Hurricane dynamic models now near St Mark's landfall. Let's see where the Euro lands at 12z.

[chaser1]

That constant convection firing just south of the COC is very impressive for mid-day with relatively modest CAPE. I believe this is the start of the CDO for Idalia. If some of that convection can rotate upshear, it's wheels up IMO.

Very cold tops in that bursting; my guess is that convective mass SW of center might maintain as a developing band. One other thing I noted is that the west side inflow cloud bands appear to be becoming tighter and moving faster as they flow into the LLC. Wouldn't surprise me to see Idalia shed an additional 2-3 mb's over the next couple of hours. Looks like the LLC's 2nd counter-clockwise loop may have slowed under what might be a west expanding MLC closer to center?

[toad strangler]

 https://twitter.com/webberweather/status/1695861391801086288

[SFLcane]

 https://twitter.com/ericburriswesh/status/1695846670662057999

[chaser1]

That's interesting. The only part of what Eric mentions regarding the Idalia's expansion that I question relates to the actual wind field in terms of the strong winds. Seems to me that with the orientation of outflow jets that appear to be in place 2-3 days from now, the inner core can't help to be limited in size. With a strong southerly outflow jet right up against the west side of the storm, and a strong northerly outflow jet hugging the storm on it's east side, I could see that potentially presenting an upper end Cat 1 or Cat 2 at landfall but limiting hurricane force winds to only extending a very small distance from center. Maybe Eric was referencing a wider breadth of TS force winds and a broader rain shield?

[Woofde]

Definitely some shear impacting Idalia at the moment. It's needs to wrap the southerly convection upshear to the North to really intensify any further.

[Iceresistance]

Definitely some shear impacting Idalia at the moment. It's needs to wrap the southerly convection upshear to the North to really intensify any further.

The upper-level anticyclone is displaced to the west per CIMSS


https://s11.gifyu.com/images/SgWlO.png

[Sciencerocks]

 https://twitter.com/DylanFedericoWX/status/1695847895956619294

[jlauderdal]

With the 12z GFS, i would expect a slight... west nudging of the cone

newest run was east of the previous run, wasn't it? and the 11AM discussion said their path may need to move further east

Yep, and the euro has come east, they will nudge it east, they dont stay off the consensus for long

[SFLcane]

 https://twitter.com/dylanfedericowx/status/1695867228241948728

[cheezyWXguy]

That moisture surge associated with the southern inflow band has now reached the center. Curious to see if this results in any intensification over the next few hours

[Sciencerocks]