Severe WX Severe Weather threat for 7/19-7/22/18

[Argus]

Meanwhile, according to the models, the threat increases for north Georgia including Athens.

 

[Mike S]

 

[akt1985]

Almost all of Tennessee is under a tornado watch as a separate watch is in effect for eastern Tennessee until 4am Eastern.

 

[rolltide_130]

Satellite trends are not encouraging for anyone hoping for storm development. Looks like the cap will hold. I'm fairly confident in saying the severe weather threat is now diminishing for North AL.

 

[HazardousWx]

Satellite trends are not encouraging for anyone hoping for storm development. Looks like the cap will hold. I'm fairly confident in saying the severe weather threat is now diminishing for North AL.

Maybe they will take us out of the watch. I have several people on standby to go in. I don't like that when there aren't even any storms approaching.

 

[MichelleH]

Storms are starting to fire up in Arkansas.

 

[rolltide_130]

Maybe they will take us out of the watch. I have several people on standby to go in. I don't like that when there aren't even any storms approaching.

Satellite is quiet as a mouse save for some upper level clouds to our NW. By now, we need to see something developing. Wouldn't be surprising to see them cancel the watch around midnight or so at this rate.

 

[akt1985]

Forget storms, will it even rain in north Alabama tonight?

 

[Taylor Campbell]

I just got to Athens, AL.

 

[Bama Ravens]

The storms in east-central Arkansas will be an issue for MS probably, but likely not AL.

 

[Taylor Campbell]

Echo popping up to my north near Parsons, TN.

 

[Taylor Campbell]

Most models don’t show things cranking up till around 04z or after. It’s only 02z.

 

[akt1985]

The storms in east-central Arkansas will be an issue for MS probably, but likely not AL.

A severe thunderstorm watch was just issued for parts of the Mississippi Delta.

 

[Chris3024]

Looks like some sort of boundary passed over the Evansville, Indiana radar. Looks like storms are starting to form along and west of that boundary

 

[KoD]

AFD Huntsville update from 9pm

Area Forecast Discussion
National Weather Service Huntsville AL
909 PM CDT Fri Jul 20 2018

.NEAR TERM...(Tonight)
Issued at 909 PM CDT Fri Jul 20 2018

The TN Valley is still playing the waiting game this evening.
Regional 00Z soundings and Univ. of Alabama-Huntsville soundings all
continue to indicate a highly unstable atmosphere. There is some
deep-layer shear in place but little low-level shear--at least for
now. Both UAH and BMX soundings show a very small cap around 800-825
mb, while the OHX sounding has it almost completely eroded. All that
is missing is some lift to erode this cap and realize the instability.
Severe convection so far has been limited to east Tennessee, but
convective initiation is occurring across Arkansas as of 02Z/9pm.

Convection-allowing models have been all over the place today. There
are signs that the 00Z CAM runs are beginning to get a better handle
on the situation but it is tough to put a lot of faith in them.
Several CAMs suggest explosive development over central/eastern
Arkansas, which then brushes NW Alabama in the 04-06Z timeframe. The
latest HRRR puts very little over the area for the entire overnight
period--but also is not resolving current upstream conditions very
well. So the 00Z CAM consensus is about the best available option
for right now. Instability is not a concern at this point, and deep-
layer shear should be fairly robust. Low-level shear will increase
over the next 2-4 hours as a low-level jet kicks into place around
the parent low, so the tornado watch seems reasonable for now.

 

[RollTide18]

Looks like some storms are beginning to pop in Middle Tennessee

 

[Bama Ravens]

Well, BMX isn’t impressed with where things stand for the overnight threat:

 

[Equus]

0-1km SRH is on the rapid rise, but gotta break the cap to get anything going. Am thinking the threat looks more isolated rather than a widespread threat for our region now, at least if the HRRR continues to have a decent handle on things.

 

[rolltide_130]

0-1km SRH is on the rapid rise, but gotta break the cap to get anything going. Am thinking the threat looks more isolated rather than a widespread threat for our region now, at least if the HRRR continues to have a decent handle on things.

Yeah that's the problem - the HRRR failed today. It failed MISERABLY today. In fact Jason Simpson even publicly joked about it on air.

I think that's a wrap on any sort of threat for North AL. There's just not much lift in TN underneath the already stout cap, and the one storm that tried immediately got shut down. The stuff in AR may make things interesting for W AL later tonight, but North AL is done.

 

[bwalk]

Better hope that cap holds. Sig Tor parameters at 9pm (cst)