ATL: CLAUDETTE - Models

[cycloneye]

 https://twitter.com/AnthonyMweather/status/1404204945734307840

[JW-_-]

[Steve]

12Z ICON is the first one to run through. Looks like a broad/weak low coming up to the SWLA coast with a lot of rain along the coast and over to SELA and coastal Mississippi. Chance of some heavy rain after landfall in northern AL and GA per ICON.

https://www.tropicaltidbits.com/analysi ... 412&fh=120

most of the heaviest rainfall on ICON is offshore in the Gulf.
https://www.tropicaltidbits.com/analysi ... 412&fh=180

GFS is out to 96 hours and is a little tighter on the circulation than the ICON. I'll post that when it runs and the CMC.

MJO looks to take a quick trip into Phases II and III, so it shouldn't be a surprise if we do get some genesis.

[Steve]

GFS is a little tighter than ICON though we may see competing centers until it gets near the coast. GFS takes it down to 1003mb and has coming in on a NNE-NE heading into SCLA. Landfall is Saturday afternoon with most of the weather out front.

https://www.tropicaltidbits.com/analysi ... 412&fh=126

GFS does have a pretty significant strip of rainfall running into Houma or so.
https://www.tropicaltidbits.com/analysi ... 412&fh=144

[Steve]

CMC doesn't really consolidate the heaviest rain with the center. It pinwheels convection on the east side up north and northeast of the center. Looks like that's where it believes the strongest weather will be.
https://www.tropicaltidbits.com/analysi ... 412&fh=144

CMC says a foot or so of rain from about Destin westward across coastal Mississippi.
https://www.tropicaltidbits.com/analysi ... 412&fh=144

[Steve]

Looking at rainfall rates from CMC, ICON and GFS before I go to sleep.

CMC
A foot or two of rain from SELA across coastal MS, coastal AL, northern Escambia County, FL, all of southern Alabama and a swath of southern Georgia.
https://www.tropicaltidbits.com/analysi ... 500&fh=168

ICON is determined to leave most of the heaviest precipitation offshore of LA, MS, AL, FL. A coastal waters/maritime storm from the ICON
https://www.tropicaltidbits.com/analysi ... 500&fh=180

GFS hasn't run as far out for total precip. However, it's completely different and focuses the heaviest rain across southern AL and then GA. Like the CMC, it shows a pretty eastern/ene hook after landfall or at least the rain that's NE of the center as that part of the system gets caught up in the westerlies.
https://www.tropicaltidbits.com/analysi ... 500&fh=144

[Steve]

I'm sticking with the rainfall forecasts since it's pretty obvious 92L isn't going to get all that strong. Most of the 10m winds are less than 30 knots on the global models. Not sure if the high-res EC has more.

CMC - at least a foot of rain across the Gulf Coast from New Orleans to Destin including all of Escambia, Santa Rosa and Okaloosa Counties.
https://www.tropicaltidbits.com/analysi ... _us_23.png

GFS - much less rain than the CMC. SCLA, SE MS and S AL.
https://www.tropicaltidbits.com/analysi ... 512&fh=150

ICON - most rain offshore. A few inches on land.
https://www.tropicaltidbits.com/analysi ... 512&fh=150

[aspen]

The most recent NAM run peaks 92L as a mid-low 990s TS near the time of landfall. That is the strongest mesoscale run so far and the NAM is known for over-estimating intensity, but none of the other models go out as far, and 993 mbar is not what I would call excessive.

[Ubuntwo]

I'm sticking with the rainfall forecasts since it's pretty obvious 92L isn't going to get all that strong. Most of the 10m winds are less than 30 knots on the global models. Not sure if the high-res EC has more.

CMC - at least a foot of rain across the Gulf Coast from New Orleans to Destin including all of Escambia, Santa Rosa and Okaloosa Counties.
https://www.tropicaltidbits.com/analysi ... _us_23.png

GFS - much less rain than the CMC. SCLA, SE MS and S AL.
https://www.tropicaltidbits.com/analysi ... 512&fh=150

ICON - most rain offshore. A few inches on land.
https://www.tropicaltidbits.com/analysi ... 512&fh=150

10m wind peaks at 34.4 kt on the 12z hires euro. Though it's usually best to take model wind forecasts with a mound of salt.

[Steve]

For sure ub. I didn't want to discount its output since that's an important model. The other 3 globals seem to like winds in the 20's. I didn't really see gales on the 12z runs otherwise.

aspen,

That's interesting at 993 (assuming the 12km run?). I don't think it'll get that deep, but you never know. I think ICON had it around 1002mb coming into Louisiana. NAM gets rightfully trashed, but I always look at those too once in range. Many hints have been derived from NAM outputs.

[Hammy]

The most recent NAM run peaks 92L as a mid-low 990s TS near the time of landfall. That is the strongest mesoscale run so far and the NAM is known for over-estimating intensity, but none of the other models go out as far, and 993 mbar is not what I would call excessive.

NAM seems to overestimate intensification rate, and gets worse the quicker the actual rate is, so it tends to do better with systems that are intensifying more slowly or steady state so this looks like a fairly realistic forecast.

[Steve]

00Z look at the GFS, ICON and CMC

GFS - Brings a broad but slightly tightening low into Cameron Parish, LA. Its heaviest squalls are NE of the point of landfall into SELA and southern MS. Then the convection fires up more in northern MS/AL/GA before washing out and merging with a front coming down near the GA/SC border. It backed off some on the rainfall which is now centered in Hancock and Pearl River Counties, MS. GFS shows more or less depression windspeeds off the LA/MS Coasts. Here's the total accumulated rainfall:
https://www.tropicaltidbits.com/analysi ... 600&fh=180

ICON - ICON brings a broad center north which then consolidates closer to shore (incoming). I feel like it's been underdoing rainfall on land the last several runs. This one brings a swath of 3-5" from SCLA up through Livingston/Tangipahoa Parishes, LA and up through most of the state of MS into Tennessee.
https://www.tropicaltidbits.com/analysi ... 600&fh=120

Canadian - CMC doesn't really consolidate a center that well. The worst convection comes up through southern MS & AL and NWFL into southern GA. It almost looks like it comes up as a warm-front. But it's really just part of a wave and/or the western push of Atlantic high pressure interacting with the low pressure to its west and SW. It doesn't consolidate low pressure in that area, just the strongest convection.

Valid 11am Saturday: https://www.tropicaltidbits.com/analysi ... 1600&fh=90

ICON had been keeping most of the rainfall offshore. However, the 00z run does drop a foot to a foot and a half across most of coastal Alabama and all of NW FL.
https://www.tropicaltidbits.com/analysi ... 600&fh=120

[JW-_-]

https://imgur.com/8BgTIjX
Bom sees roughly 70 mph gusts atm on its 00z.



https://imgur.com/SdDLdzP
Precip forecast atm.

[Steve]

12z NAM 12km

Landfall as a tightening 993mb system in Cameron/Vermilion Parishes Saturday afternoon. I think NAM 12km might be too slow. It meanders and loops the center a couple of times which is why it's slower than the globals. Most rain is offshore and around coastal Louisiana.
https://www.tropicaltidbits.com/analysi ... 1612&fh=78

3km, FV3 Hi-Res should be finished shortly but both only run out 60 hours.

[Steve]

NAM 3km is a little closer to the Texas coast and at 993mb. It's a little out of range for 3km, so either this little loop is right before it lifts North or NNE per the 12km.
https://www.tropicaltidbits.com/analysi ... 1612&fh=60

FV3 High Resolution is looser and a bit east of the NAM's position in 60 hours (valid for 7pm Friday)
https://www.tropicaltidbits.com/analysi ... 1612&fh=60

ICON (already out to 33 hours), GFS, CMC, Euro are next up.

[hurricane2025]

models will suck till we have a center

[Steve]

models will suck till we have a center

They're probably not going to suck that badly. This isn't going to be a powerful system where a few miles one way or the other could put an area in jeopardy. Would you suggest they sucked up to this point considering most of the globals called this area weekend before last? I'd say that's progress. Otherwise, it's just fine point details. So they won't suck for this system.
---------
TT has a gap between 60 and 87 hours for the ICON. Appears to hit SWLA as a decent east-weighted system (which we've known it would be for a week). Total Accumulated Precipitation (which is what I'm interested in since I'm tracking the outputs) has the heaviest rainfall in coastal MS through 96 hours.

https://www.tropicaltidbits.com/analysi ... 1612&fh=87

Rainfall
https://www.tropicaltidbits.com/analysi ... 1612&fh=96

[Steve]

GFS 12z landfalls SWLA 7am Saturday
https://www.tropicaltidbits.com/analysi ... 1612&fh=72

Heaviest rainfall is through southern Mississippi and up the MS/AL border.
https://www.tropicaltidbits.com/analysi ... 1612&fh=96

[BobHarlem]

12 HWRF got suckered into the East Pacific, HMON seems to have the right area though. These 12Z models are very questionable init at least from what I see on the satellite. The EPAC is really confusing it.

[eastcoastFL]

Who’s up for some spaghetti ?