Severe WX Severe Threat 17-18 March 2021

[Mike S]

first big lightning strike IMBY (Providence area of Huntsville) about 10 minutes ago. Shook the building.

 

[Richardjacks]

Could the storm mode be a bit messier than expected because the latest HRRR/NAM show a more positively tilted trough vs. earlier runs?

I am just pondering aloud as to just what could hopefully limit the potential of this event.

actual soundings show a stronger cap than modeled, this should suppress a bit more

 

[The Nino]

does anyone have map of current warm front placement. I know its fairly easy to pick up on radar but curious still.

 

[JayF]

3k 12z nam has SBLi's in central Miss approaching -10!!

That is intense

 

[KevinH]

Also this in the newest SPC discussion; even if you're not in the enhanced risk, don't count yourself out if you're in the west metro, these storms definitely won't care about the risk categories.
View attachment 7033

That would be me. I live right on the AL/GA border in Columbus.

*sigh*

 

[CheeselandSkies]

1KM EHIs across west Alabama actually increase from 00Z to 03Z on the 12Z NAM. Probably a sign of the LLJ kicking in.

 

[Casuarina Head]

actual soundings show a stronger cap than modeled, this should suppress a bit more

But could the more positively tilted trough on the latest HRRR/NAM runs reduce the potential for numerous discrete long-trackers?*

*At least before sunset

 

[Kory]

But could the weaker, more positively tilted trough on the latest HRRR/NAM runs reduce the potential for numerous discrete long-trackers?*

*At least before sunset

A positively tilted trough is what favors isolated convection due to subtle forcing over the warm sector versus a negative tilt trough with a lot of forcing.

 

[NorthGaWeather]

does anyone have map of current warm front placement. I know its fairly easy to pick up on radar but curious still.

Just a quick look would lead me to believe it is sitting somewhere just north and east of TCL-MGM-TOI.

 

[speedbump305]

All the towns in the april 27 outbreak are in this outbreak let’s pray that it doesn’t affect some of the same places. prayers from texas

 

[CheeselandSkies]

One thing I'm noticing is a relative lack of analogs on the 12Z NAM forecast soundings valid for 21Z and 00Z (Thursday). Most of them show "No Quality Matches." @Fred Gossage , what if anything is the significance of that?

Among the few notable ones that I can find are:

11/15/1987 at KGGG (East Texas Regional Airport): Tornadoes caused 10 fatalities in Texas that day.
5/30/2004 at KIND: Numerous tornadoes in Indiana, F2 hit Indianapolis itself.

These appear on forecast soundings from both the "regular" and "nest" or 3KM NAMs.

 

[Casuarina Head]

A positively tilted trough is what favors isolated convection due to subtle forcing over the warm sector versus a negative tilt trough with a lot of forcing.

I thought so. Anyway, I would like to amend my earlier post: the vortex is actually deeper on the latest runs, hence stronger wind fields.

 

[Kory]

After looking at the 12z WRF suite and 13z HRRR, make sure there is a way to get warnings and you respond quickly to them. They are flat out ugly.

 

[The Nino]

What is the latest thoughts on the Huntsville area? Looks like all the models have the wedge holding out over NE Alabama. Hope that holds.

 

[TuscWeathergrl]

Nasty cell that cuts through Tuscaloosa

Let’s not summon the cell here. That model can kiss my booty

 

[Jimruns]

 

[Jpgood97]

Are we seeing more lingering convection this morning is N AL and southern TN than what was forecasted, or are we still on par with forecasted model guidance?

 

[MNTornadoGuy]

13Z HRRR is terrifying. It has multiple discrete supercells tracking through AL. Let's hope that doesn't happen.

 

[sak]

seems like the wedge progressed a bit further west than expected. i realize it is still forecasted to lift out of the birmingham metro, but really seems that unless it starts hauling butt, the threat will be diminished for places like atlanta, chattanooga, and rome, ga. maybe even as far SW as places like gadsden, alabama

i know there could be a sharp cutoff of severe weather parameters. here’s to hoping it is 50 miles further southwest than was suggested yesterday.

 

[The Nino]