Severe WX Severe Threat 25 March 2021

[Ingyball]

So one thing about the HRRR, even with the messy storm mode the environment behind it is still more than suitable for strong tornadoes in northern Alabama. You combine that with possible outflow boundaries from the previous storms that discrete cells could ride on and then you're looking at trouble. 1 to 2 hours of destabilization would only add fuel to the fire.

 

[Richardjacks]

IF the 0z nam is right, this will be a high end event. 996mb low near Memphis in late March with readily accessible high Td's and clean warm sector. At face value- recipe for disaster.

 

[Tomcats Forever!]

NAM says what showers at 10am tomorrow...very concerning run.

Ah, crap. I've taken to using the NAM to sniff out flies in the ointment. If it's not seeing any this close...

 

[Kory]

So one thing about the HRRR, even with the messy storm mode the environment behind it is still more than suitable for strong tornadoes in northern Alabama. You combine that with possible outflow boundaries from the previous storms that discrete cells could ride on and then you're looking at trouble. 1 to 2 hours of destabilization would only add fuel to the fire.

Correct...and south of that complex is where discrete convection would take hold in a cleaner warm sector.

 

[Clancy]

IF the 0z nam is right, this will be a high end event. 996mb low near Memphis in late March with readily accessible high Td's and clean warm sector. At face value- recipe for disaster.

Goes to show nothing here is settled yet. Don't write *anything* off, but don't mentally go all in. Still a long way to go and lots more data to take in.

 

[Jacob]

IF the 0z nam is right, this will be a high end event. 996mb low near Memphis in late March with readily accessible high Td's and clean warm sector. At face value- recipe for disaster.

Oddly enough, the actual storm depiction from the 0z NAM is a big nothing-burger for all but extreme N Alabama. It seems to be on an island all by itself in that regard though.

 

[The Nino]

3k nam showing some real high params but not much convection out in front of the QLCS.

 

[Fred Gossage]

The NAM's convective parameterization scheme is explicitly designed to not initiate if the mid-levels are dry.

 

[Richardjacks]

The NAM's convective parameterization scheme is explicitly designed to not initiate if the mid-levels are dry.

You do understand that the NAM isn't a CAM right? It isn't able to process convection/thunderstorms.

 

[Austin Dawg]

Don't sleep on this evening in Texas either. We could definitely see a few tornadoes there.

I expect a watch before 10.

 

[Jacob]

The NAM's convective parameterization scheme is explicitly designed to not initiate if the mid-levels are dry.

Well that certainly explains it. In an odd way, the NAM not showing it could be interpreted as a worse sign. That'd be a fun thing to explain to some.

 

[Keldeo]

This sounding from the NAM is uhhh not good. Northern Mississippi

 

[Richardjacks]

Well that certainly explains it. In an odd way, the NAM not showing it could be interpreted as a worse sign. That'd be a fun thing to explain to some.

Right, but the fact it has nothing tells me ALOT!

 

[Fred Gossage]

You do understand that the NAM isn't a CAM right? It isn't able to process convection/thunderstorms.

And its parameterization scheme to make up for that is explicitly designed to not model activity if there is dry mid-level air. It's an extremely well known bias in the scheme. Rich Thomspon talked about it in detail a few years ago in his tornado forecasting video series.

I think we're actually trying to hint at the same point lol

 

[Richardjacks]

Today's 12z ens run. I am sure the SPC is waiting to see if the 0z run looks anything like this.

 

[HazardousWx]

Today's 12z ens run. I am sure the SPC is waiting to see if the 0z run looks anything like this.

That looks to be the area mainly affected on the 17th, right?

 

[MattPetrulli]

00z CAMs are pretty outbreakish, especially ARW.

 

[Keldeo]

 

[MichelleH]

View attachment 7454
Today's 12z ens run. I am sure the SPC is waiting to see if the 0z run looks anything like this.

That track in Cullman County goes right over my house.

 

[Marshal79344]

At this point, tomorrow is not a question of will the conditions allow a tornado outbreak to occur. It's a question of how severe will the tornado outbreak be. The floor is high, but the ceiling is simply beyond comprehension.