ATL: DELTA - Models

[Steve]

00z runs will be the one to watch with the extra data that will be ingested, 18z don’t really matter right now, big runs will be tonight hopefully models start nailing it down

They had been getting a steady diet. What I want to know from the 00z runs is what happens with the push of the ridge. Any stronger and it's going to be on the western edge of the expected tracks. No doubt the flow will eventually pick it up, but it could be more Beaumont/Lake Charles if it is stronger. If it's weaker (and we aren't talking by much at all), it's New Iberia or Morgan City. Weaker and Houma over to New Orleans or Slidell could be a landfall point. They've mostly been close with an eastern or western outlier, but this is the most consensus they've had in advance for a while.

[Emmett_Brown]

Maybe it’s just me but the further west these shifts seem to happen the more pronounced the hook back N and NE becomes. If that’s the case it may become more of a trajectory of landfall for those in the bullseye... or if it slows down upon approach that could send it much further East as it closes in on land. Just my thoughts considering it’s October and that usually seems to favor stronger right turns

I agree, in some setups this can happen. However, this time the west trend has been because the ridge over FL has been getting progressively stronger on each run, and the trough that is supposed to turn it NE has been getting progressively weaker and later. So I think in this case, the west trend may be legit. This could certainly change of course... interaction and absorption of Gamma is still a wild card in my mind.

[Steve]

Climo is certainly against a Texas hit, but Delta certainly has me keeping an eye on the model runs. Not as much as it was for Laura (I think I am storm fatigued). But at any rate, the gut feel is Delta stays well east of TX. Somewhere south of Lafayette (Pecan Island area).

You know old friend, I would agree with you 100 percent in all years but this one. This one is for the record books. To have an October storm, this strong, is mind boggling. To be into the Greek alphabet for only the second time, is mind tripping. I am saying, throw climo out the door...I think 2020 took it, burned it and spread it for compost..LOL

You know it. Here's what we have going against it getting out to say 95W. Note on the upper water-vapor loop below that the existing boundary/front is being pushed by a new airmass coming down. Their boundaries are almost together. Flow to the south and southeast of that is out of the southwest. What I think is happening is the cut off low off California is feeding the upper trough moving down into New Mexico with the east side coming up straight out of the SW and from the Pacific. Unless the trough was to split and the eastern side lift out, it simply can't get all the way to the Texas coast from the east or southeast. Front is going to be held up for a few days as we are kind of in Indian summer. Nothing is in a hurry to move in the upper atmosphere across the USA. Plus, the ridging coming in through Florida is blocking the pattern from the east. You can see that the dry line has already cleared the coast in extreme SE FL. This is the stuff to watch the next 2-3 days if you're on either side of the periphery of the cone.

https://www.star.nesdis.noaa.gov/GOES/conus.php?sat=G16

[HeeBGBz]

I have a very hard time believing Delta will not hook NE
before reaching anywhere near Lake Charles. IMO

It always seems to hook east. I'm watching to see when it's going to do a turn.

[Tireman4]

Climo is certainly against a Texas hit, but Delta certainly has me keeping an eye on the model runs. Not as much as it was for Laura (I think I am storm fatigued). But at any rate, the gut feel is Delta stays well east of TX. Somewhere south of Lafayette (Pecan Island area).

You know old friend, I would agree with you 100 percent in all years but this one. This one is for the record books. To have an October storm, this strong, is mind boggling. To be into the Greek alphabet for only the second time, is mind tripping. I am saying, throw climo out the door...I think 2020 took it, burned it and spread it for compost..LOL

You know it. Here's what we have going against it getting out to say 95W. Note on the upper water-vapor loop below that the existing boundary/front is being pushed by a new airmass coming down. Their boundaries are almost together. Flow to the south and southeast of that is out of the southwest. What I think is happening is the cut off low off California is feeding the upper trough moving down into New Mexico with the east side coming up straight out of the SW and from the Pacific. Unless the trough was to split and the eastern side lift out, it simply can't get all the way to the Texas coast from the east or southeast. Front is going to be held up for a few days as we are kind of in Indian summer. Nothing is in a hurry to move in the upper atmosphere across the USA. Plus, the ridging coming in through Florida is blocking the pattern from the east. You can see that the dry line has already cleared the coast in extreme SE FL. This is the stuff to watch the next 2-3 days if you're on either side of the periphery of the cone.

https://www.star.nesdis.noaa.gov/GOES/conus.php?sat=G16

I know. I agree with you. You are correct in all you say. We just watch and wait on the NE turn.

[Steve]

ICON has a landfall in SWLA at 7pm Friday @ 982mb on the Rockefeller Wildlife Refuge near Pecan Island. Recall it and the EC have been on the western side with Delta.
https://www.tropicaltidbits.com/analysi ... 0618&fh=78

[N2FSU]

18z GFS
with some interesting subtle changes:

* slightly slower to the Gulf coast

*stays stronger inland after landfall on Gulf coast

*now goes due east across northern Miss, northern AL and makes it into northern GA before ejecting up and out





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[bella_may]

18z GFS https://uploads.tapatalk-cdn.com/20201006/86de09c0ff338daba683257f0a3e83d8.jpg
with some interesting subtle changes:

* slightly slower to the Gulf coast

*stays stronger inland after landfall on Gulf coast

*now goes due east across northern Miss, northern AL and makes it into northern GA before ejecting up and out

https://uploads.tapatalk-cdn.com/20201006/8c24bb2167d1dc167052746d0f7ef434.jpg
https://uploads.tapatalk-cdn.com/20201006/5d1f425e01f449f6af17d6f775736f15.jpg


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Stronger trough?

[Steve]

GFS landfalls at 7pm Friday which is the same time as ICON but shows it stronger (965mb vs. 982) and farther east over by New Iberia.
https://www.tropicaltidbits.com/analysi ... 0618&fh=78

[N2FSU]

Here is the 12z GFS for comparison:





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[Steve]

18z GFS https://uploads.tapatalk-cdn.com/20201006/86de09c0ff338daba683257f0a3e83d8.jpg
with some interesting subtle changes:

* slightly slower to the Gulf coast

*stays stronger inland after landfall on Gulf coast

*now goes due east across northern Miss, northern AL and makes it into northern GA before ejecting up and out

https://uploads.tapatalk-cdn.com/20201006/8c24bb2167d1dc167052746d0f7ef434.jpg
https://uploads.tapatalk-cdn.com/20201006/5d1f425e01f449f6af17d6f775736f15.jpg


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Stronger trough?

No. It's been very consistent with landfall and upper patterns from 00-06-12-18. This is set to 78 hours which is landfall. If you only click on the times of the previous model runs, it will back up that many hours to show you where it had it at the same actual time on a prior run. So if you click 12z, 06z, 00z, and as far back as you want to go, it will still bring you to Friday at 7pm. So check it out.
https://www.tropicaltidbits.com/analysi ... 0618&fh=78

Edit to say N2 is right about after landfall things have evolved. I'm just talking about landfall since you're 'over there on the MS Gulf Coast probably somewhat nervous like the rest of us.

[N2FSU]

Yes sorry for any confusion, I was really talking about movement after landfall. It just emphasizes that the front IS out there, and any significant slowdown of Delta approaching the coast would mean an eastern shift of the landfall.


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[Steve]

No worries. Here are some thoughts on the Gulf period starting tomorrow afternoon. I was watching WWL met Chris Franklin's update from an hour or so ago, and he offered a couple of cautions with the track. He was the one guy on tv yesterday who said don't expect any further shifts east - if anything, they would be west. So not only does he have some credibility, he was good recently with this storm.

His idea is that the system may not weaken and could easily landfall as a major. He said that he feels like the fast motion (it's currently going 17mph WNW) across the Gulf will not allow the deeper, cooler waters to weaken it all that much. He said that a faster moving storm also might not turn as sharply which certainly brings points a little farther west than the NHC's track into play if that occurs. Also, the deeper water is warmer in the Western Gulf than it is on a line from the Yucatan up to Louisiana. We'll see how it plays out.

Meanwhile, HMON has an eastern component at 92.5W once up to 27.5N. It basically comes up around 92.7 but starts fading back. Landfall is approximately 91.8W heading NNE. It hits between the 3 hour plots, so it's clearly got it moving pretty fast at landfall Friday night in the upper 940's.

[supercane4867]

Both HWRF and HMON have a sub-940 strong CAT4 in the Gulf

[Nimbus]

Both HWRF and HMON have a sub-940 strong CAT4 in the Gulf

18Z takes Delta way west of 93 as a real surge monster so Texas may get flood warnings.
I'm not familiar with the surge modeling for Galveston island area?

[Steve]

Yeah, it's coming up about half a degree farther west than the HMON and looks to be similar to the EC and ICON though possibly split between the western models and the ones going in near Morgan City.

[supercane4867]

No weakening prior to landfall. 945mb 110kts

[stormlover2013]

Yep, hwrf shift west

[SoupBone]

Will tonight's HMON/HWRF have the balloon data?

[Steve]

Solid Cat 3 for the HWRF Friday night right at Pecan Island. Look out Lafayette, New Iberia and similar. There are about 500,000 people who live in the Lafayette metropolitan area which is double and a half again what they have in Lake Charles (roughly 200k).