ATL: DELTA - Post-Tropical - Discussion

[Steve]

Okay, so we are on advisory # 9 and the forecast track has shifted west on every single one since it's inception. No surprise that right after the NOAA G-IV made it's first run that the track shifted back to the east. The 5pm advisory had Delta making a Gulf coast landfall at 92.9. The 11pm advisory has made it's very first EAST shift to 92.2. Curious to see if the east shifts continue....? My money is on that they do.

Is it maybe down to a few miles this way or that way? Outside of the EC and ICON, most other models bring it on the west or east side of Vermilion Bay. So does the NHC. Maybe landfall somewhere in the low 92'sW?

Hurricanes and CMC are running now. I'll wake up later in the middle of the night and look at the Euro. But it isn't calling me to say up another hour and a half.

[Keldeo1997]

Getting better

[ElectricStorm]

Looks like or it appears that a larger eyewall is redeveloping.

https://i.imgur.com/JyYKYzd.gif

Looking at that, it doesn't appear that it will be tracking over very much land before reemerging in the gulf. If this does indeed end up as the new core and is able to build it before landfall it probably won't affect it that much and it will be able to pick up right where it left off once over water again.

[ElectricStorm]

More -80C tops firing on the Western Side

[wx98]

Extrap. pressure is up about 4 mb this pass. FL/SFMR blend is Cat 1, at least based on that pass...

[wx98]

Looks like or it appears that a larger eyewall is redeveloping.

https://i.imgur.com/JyYKYzd.gif

Looking at that, it doesn't appear that it will be tracking over very much land before reemerging in the gulf. If this does indeed end up as the new core and is able to build it before landfall it probably won't affect it that much and it will be able to pick up right where it left off once over water again.

It may miss Cozumel to the north. Earlier it looked like Cozumel or south would be more likely, but it swung north in relation to potential landfall since this intensity downswing has been ongoing.

[drezee]

 https://twitter.com/andretrotter/status/1313702292550496257

[us89]

Something I think is getting lost in all the "this storm is weakening, it won't hit cat 5 anymore" talk is this storm is absolutely not done after it hits the Yucatan.

Sure, it weakened a lot after the pinhole eye collapsed. Is the current 115 kt too high? Almost certainly. But given the very favorable conditions otherwise present, if the storm can organize another core, we could still see it ramp back up into a major hurricane before it hits Mexico tomorrow.

It will probably weaken some as it moves over land. But the Yucatan Peninsula is very flat, and Delta will be moving fairly fast and likely won't spend any more than 4-5 hours over it as it will clip the northeastern corner. So while there will be some weakening with land interaction, I don't see the intensity coming down a whole lot during this period.

And once Delta moves back over water into the Gulf, it will once again encounter very favorable conditions for intensification. Models have been hinting for quite a while now that this is where it will reach peak intensity (this was the case even before the first core collapse). And here's the thing: despite the cooler SSTs further north and the possibility of some stronger wind shear, most recent model runs are not showing a whole lot of weakening upon landfall. Even the GFS has this strengthening into the 950s in the Gulf before landfalling in the US as a ~960 mb storm. HWRF suggests landfall pressure could be as low as the high 940s.

This is still very much a major threat for Louisiana and the rest of the Gulf Coast.

[Keldeo1997]

Big Elliptical eye open to the North

[Cyclenall]

To summarize the day's events, we went from one of the most explosive periods of intensification seen in the Atlantic, to an infrared appearance that can only be described as crap. I've never seen that. Remember the hype when everyone thought this was going to be one of the strongest hurricanes recorded in the Atlantic (me included)? I 'member . I knew Gamma was going to run his Gambit!!

Shear working its magic on Delta.....lets hope the inner core can't recover.....MGC

Why does shear always show up when it's not supposed to (per the models within the last 24 hours) and isn't there when it was forecast to be? I bet you there's a lot less shear as Delta approaches the US Gulf Coast than was forecast as of yesterday (although SSTs will still put a cap on intensity at that point).

I keep talking about magical windshear that always shows up somewhere when not anticipated. You'll have shear that is stronger than what is hitting Delta and do nothing and then with today you'll have some random magic come out of nowhere that not a single person even mentioned this morning that weakens it instead of a CAT5 and a legendary one at that? A La Nina developing, record OHC, hyperactive season, and a OCT WCarb hurricane and this happens . Then you have Hurricane Michael in 2018 making LF as a CAT5?

The Hype from this storm seems to have died down pretty quickly...

Like a searing hot potato in our hands, our hype dropped as soon as the flattening was noted on satellite on the west quad. I wouldn't let my guard down though in such strange times - Delta is going to probably do something nasty at some point.

[hurricanehunter69]

Several things I'm noticing about Delta currently. 1) Delta is definitely looking healthier and possibly strengthening. 2) Delta has definitely grown much larger in size. 3) Delta is at the very least jogging /moving more northerly.

[Jr0d]

While the storm weakening is good news, the wind field has gotten bigger. The storm will grow in size before it makes landfall in the northern Gulf of Mexico. This is bad news for the storm surge threat. Hopefully the fast forward motion will help minimize surge.

After Laura and Sally's surge was not nearly as high as expected in a lot of areas, my concern is people will not take Delta's surge warning as serious.

[Frank2]

I noticed the surge of dry air approaching from the NE on Monday but thought it best to keep it to myself - it's knocking Delta off it's pins the past 6 hours.

https://www.nhc.noaa.gov/text/refresh/M ... 0552.shtml

[CrazyC83]

The larger eye means that the wind field will be much larger. Instead of a tiny swath of destructive winds (like a tornado) we'll have a decent sized swath of damaging winds.

[DestinHurricane]

While the storm weakening is good news, the wind field has gotten bigger. The storm will grow in size before it makes landfall in the northern Gulf of Mexico. This is bad news for the storm surge threat. Hopefully the fast forward motion will help minimize surge.

After Laura and Sally's surge was not nearly as high as expected in a lot of areas, my concern is people will not take Delta's surge warning as serious.

for Laura they predicted 15-20 and 17 feet was recorded. Sally had higher than expected surge, particularly from Pensacola to Destin.

[Hammy]

One thing I'm curious, and I might've missed it as I haven't been online much the last few days, why is the pressure so high for the winds? 956mb earlier at 145mph and now Cat 3 with 972mb.

[Jr0d]

for Laura they predicted 15-20 and 17 feet was recorded. Sally had higher than expected surge, particularly from Pensacola to Destin.

Laura's surge was not as widespread as originally forecast....the 17' recorded surge was in a rural area.

With Sally, Mobile Bay got lucky because where Sally hit. The surge there was no where near the forecast in Mobile Bay.

While most of us on here know why the left side of the storm will have much less surge or even lower water levels, this is not the case for many in the warning area. When the surge is significantly lower than forecast(as a result of being on the left side), this can lead to complacency for future storms.

[Jr0d]

Not the best radar images from Cuba, but enough to get a decent fix on Delta. The center is going Northwest, on this course it will barely clip the Yucatan Peninsula. Good news for them, bad news because the limited land interaction will not weaken the storm.
http://www.insmet.cu/asp/genesis.asp?TB ... AXw01a.gif

[CrazyC83]

One thing I'm curious, and I might've missed it as I haven't been online much the last few days, why is the pressure so high for the winds? 956mb earlier at 145mph and now Cat 3 with 972mb.

The storm had a very tight core and was beneath a ridge, hence it would have higher winds than expected.

[otowntiger]

One thing I'm curious, and I might've missed it as I haven't been online much the last few days, why is the pressure so high for the winds? 956mb earlier at 145mph and now Cat 3 with 972mb.

. For one thing it doesn’t seem to have winds that would support even cat 2 currently. So the pressure and wind may be more aligned than it seems. NHC unwilling ( understandably so) to make drastic drops in categories in just one or two advisories. It’s a tough balancing act.