Severe Weather Threat - November 29th-30th, 2022

[Shakespeare 2016]

The Storm Prediction Center outlined a moderate risk in their first Day 2 outlook. The 06z HRRR run is near completion.

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I have seen a number of temperatures in the 65F to 71F range and dews in the 63F to 69F range at 10:00 pm on Tuesday . I guess I will assume that is high enough for this time of year.

 

[Shakespeare 2016]

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WOW!!!

 

[Fred Gossage]

It's still early in the game with this one in terms of trying to figure things out with the CAMs, but after looking at the last couple HRRR runs, the WRFs, and the 3k Baron we have in house at the station, I'm definitely getting the vibe that this may be another event with southeast displacement. I could easily see the main corridor of the tornado threat being mainly west central to northeast Mississippi (with a Greenville to Iuka line being the northern boundary) and then that extending over into west central Alabama and maybe portions of northwest Alabama near and south of the Tennessee River.

And I still think we'll need a SLGT expansion down over the MOB CWA for a "sleeper" mini tornadic supercell threat...

 

[Fred Gossage]

https://www.tnvalleyweather.com/pos...awn-wednesday-but-the-threat-isn-t-guaranteed For those of you in northwest Alabama, southern middle Tennessee, and northeast Mississippi, this is a long and detailed (with graphics) read on our thoughts on the forecast desk... and why we think the severe storm and tornado potential in the local area very much isn't set in stone, even though the threat definitely is conditionally there.

 

[Austin Dawg]

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This would be a nightmare scenario for me personally

 

[CheeselandSkies]

06Z HRRR is ugly. Sups galore across MS, northern LA, western TN, even parts of western AL that are currently only in a Marginal risk per SPC. And that's just through 00Z Wednesday, I haven't even gotten into the overnight stuff yet.

 

[Lake Martin EF4]

06Z HRRR is ugly. Sups galore across MS, northern LA, western TN, even parts of western AL that are currently only in a Marginal risk per SPC. And that's just through 00Z Wednesday, I haven't even gotten into the overnight stuff yet.

Do any of those HRRR sups go into Fayette Co, TN?

 

[CheeselandSkies]

Do any of those HRRR sups go into Fayette Co, TN?

The main one I see looks to go a bit north of there, through northern Haywood/southern Crockett. Of course, there's a margin for error on CAM simulations especially at this range. Fayette Co. is very much in the risk area.

 

[tennessee storm chaser]

The main one I see looks to go a bit north of there, through northern Haywood/southern Crockett. Of course, there's a margin for error on CAM simulations especially at this range. Fayette Co. is very much in the risk area.

Getting close my house cheese … see that run. It is ugly … I’m 20 miles east Haywood if that far

 

[Taylor Campbell]

The Nadocast has this-

 

[xJownage]

I'm looking at the Monroe, LA area tomorrow for initiation of something with more high end risk. I'm concerned with crapvection atm. Given the poor lapse rates, it's going to take time for storms to get going - and with the lack of any capping or EML later in the day, I have a feeling storms aren't going to have enough space to mature into stronger supercells that can tap into the low level environment.

That being said, as a 3cape truther, this event looks to be significant.

I think CAMs are overplaying the SFC wind backing in the southern half of MS. I'm not seeing this stronger, high end tor risk down there as I think hodos are going to be more straight than the CAMs are indicating. The environment has stayed pretty static with very minimal shifts in subtropical jet streak, I wouldn't buy a southern shift in storm mode yet, though it's possible since these subtropical jet maximums can be quite finnicky, and are more sensitive to mesoscale processes than amplified polar troughs.

 

[Justin Hindman Hindy]

In my opinion, the mdt needs to be adjusted south.

 

[Justin Hindman]

Can we pin this to the top please

 

[Taylor Campbell]

Can we pin this to the top please

@WesL @StormStalker @KoD
@Lori

 

[KevinH]

New D2 is incoming….

 

[UK_EF4]

Expanded I see

 

[UK_EF4]

From just looking through the latest HRRR, pre frontal confluence zone looks likely to be around the black line, and then moving E through the day. Along it and to the east as well, I'm guessing we will probably see some supercells with tornadoes forming. Even though LLJ may not be some crazy 60-70kt LLJ like some past events, the 45-55kt which is being shown definitely seems to be enough for dangerous storms, especially with some forecast soundings pulling 400 0-1km SRH combined with 1,500 j/kg - not something you ever really want to see forecast with a discrete storm mode. Similarly to what Fred Gossage said, I remember watching a Rich Thompson video where he mentioned how just because instability drops off doesn't mean the storm will instantly die, and I think that could apply here with supercells developing in richer moisture and more instability possibly travelling further E into 60-65f dews and 500-1000j/kg as well.

 

[xJownage]

Another factor worth noting: CAMs are significantly underperforming on thermals right now, which is typical for the cool season. I also think this is why the CAMs, and consequently the ensembles, are missing the northern end of the threat.

 

[StormStalker]

@WesL @StormStalker @KoD
@Lori

Done.

 

[OHWX97]

Here's some good news. Scheduled maintenance on KLZK has been postponed until after tomorrow's event.