Severe WX Severe Wx Outbreak March 1st- 3rd, 2023 - Southern States, MS/OH/TN Valley

[CheeselandSkies]

GFS is the definition of consistency with it's last 6 runs.

A potential significant event is on the horizon. View attachment 18179

Except that the 12Z GFS is now back to the ultra-progressive solution, with the warm sector east of Alabama by noon Friday.

Same issue as with the upcoming system negating a significant early-season tornado event for the Midwest on Monday...thing just moves too darn fast.

 

[UncleJuJu98]

Except that the 12Z GFS is now back to the ultra-progressive solution, with the warm sector east of Alabama by noon Friday.

I'm not talking about Alabama in particular more so for the southeast this threat could end up more Georgia and east Alabama than just the state of Alabama. Just a lot of consensus with the GFS for a potential severe event in the southeast.

But yeah I'm not so sure this will be as progressive as modeled with the 12z seems unlikely a surface low will bomb out over west Tennessee lol. It would break the record by a longshot for deepest surface pressure. Probably see a mid-upper 980s with a less
progressive push if I had to guess.

Wait I'm probably thinking of something else when you say progressive are you talking about a more west to east motion with the system? If so yeah it wouldn't be much of a warm sector to work with lol

 

[UncleJuJu98]

Except that the 12Z GFS is now back to the ultra-progressive solution, with the warm sector east of Alabama by noon Friday.

Same issue as with the upcoming system negating a significant early-season tornado event for the Midwest on Monday...thing just moves too darn fast.

I see what you mean on a progressive system being detrimental to a severe event. Lol I had to do some research Always learning new stuff. Usually a lagging cold front is best.

Always so much new stuff learned and too learn when it comes to weather hahah

 

[UncleJuJu98]

Are we dealing with a dryline or cold front?

 

[UK_EF4]

Are we dealing with a dryline or cold front? View attachment 18181View attachment 18182

A cold front. Almost always drylines will have very little temperature difference on each side, but a strong dew point gradient. Typically cold fronts will have strong wind shifts as well.

 

[JPWX]

The 12z GFS has dewpoints near 70 at 126 hours.

 

[Tennie]

Take a look at that hodo (over N GA at 21Z Friday 3/03). I think it's trying to escape.

View attachment 18177

I can practically hear that hodograph yelling out, "MY PEOPLE NEED MEEEEEE!"

 

[UncleJuJu98]

12z euro operational still with that snow look.
It's ensembles moved a tad more east with the ejection.

While the 12z GFS ensembles moved a tad more east.

 

[UncleJuJu98]

I would like to note even with progressive systems significant outbreaks still can occur. Was doing some research. Super Tuesday was progressive as well as the Easter 2020.

With the warm sector possibly being already ripe like the picture jpwx showed above with dew points near 70 before the event the previous day. Due to a semi stationary warm front to the north, instability could already be there.

Although I'm not liking that the euro ensemble's are nudging east on ejection usually the euro has been my backbone on reliable trough ejection forecasting lol

 

[UK_EF4]

I would like to note even with progressive systems significant outbreaks still can occur. Was doing some research. Super Tuesday was progressive as well as the Easter 2020.

With the warm sector possibly being already ripe like the picture jpwx showed above with dew points near 70 before the event the previous day. Due to a semi stationary warm front to the north, instability could already be there.

Although I'm not liking that the euro ensemble's are nudging east on ejection usually the euro has been my backbone on reliable trough ejection forecasting lol

It isn't just the fact that a trough is progressive, the main issue here from the trough being progressive is that all the favourable parameters are during the early-mid morning, which helps to lower the severe threat. Easter and Super Tuesday (while being long-duration) both benefited from parameters at peak heating, while some of the storms continued into the morning after (especially Easter to my memory). Doesn't mean severe can't happen though as you say, just reduces the maximum potential.

 

[UncleJuJu98]

It isn't just the fact that a trough is progressive, the main issue here from the trough being progressive is that all the favourable parameters are during the early-mid morning, which helps to lower the severe threat. Easter and Super Tuesday (while being long-duration) both benefited from parameters at peak heating, while some of the storms continued into the morning after (especially Easter to my memory). Doesn't mean severe can't happen though as you say, just reduces the maximum potential.

I'm not sure what the disagreement here is lol. You don't have to reach max potential to have a significant event, and you don't always have to have peak heating to have those events but it does help. Peak heating isn't the only thing that produces instability, a deep surface low produces significant height falls to the southeast of it which also heightens instability along as having a very strong LLJ in the gulf.
With those two events we didn't have a deep surface low breathing down our neck lol.

Anyways timing will tinker like it always does leading up to a event. Good post though.

 

[UK_EF4]

I'm not sure what the disagreement here is lol. You don't have to reach max potential to have a significant event, and you don't always have to have peak heating to have those events but it does help. Peak heating isn't the only thing that produces instability, a deep surface low produces significant height falls to the southeast of it which also heightens instability along as having a very strong LLJ in the gulf.
With those two events we didn't have a deep surface low breathing down our neck lol.

Anyways timing will tinker like it always does leading up to a event. Good post though.

Haha didn't think it was a disagreement I just meant to add a bit extra on to your post

But back to my initial point, in a situation like some of the runs, especially the last few GFS runs, the background synoptic pattern, including height falls and a strong low as you say, with sufficient moisture, do have a naturally pretty significant parameter space. Yet having no/very little solar heating can really limit CAPE, and while you are right it is definitely not essential as CAPE is not just about surface temp etc, that extra heating can lead to that 1500-2000j/kg of CAPE which makes an event a lot worse especially with the stronger wind shear. And While I'm sure that if current GFS runs verified perfectly there would be a significant QLCS at least, it realistically wouldn't be bad as if all that happened during peak heating.

But as you say just because an event doesn't reach its peak potential doesn't mean its not significant, and as both you and I have been saying these long range events are bound to change in timing - hence why I haven't been making a big thing of this timing issue and only mentioning it as a bit of side note being one of the only main limiting factors I see at this stage if some of the GFS runs were to verify.

And a small side note: Going by some ensembles and trends, I wouldn't even be *too* surprised to see the main focus of this event possibly shifting to the evening of the 2nd, though that isnt supposed to be any sort of forecast haha

 

[UncleJuJu98]

I've always had a hard time wrapping my head around height falls but this is a general diagram I guess.

 

[UncleJuJu98]

Haha didn't think it was a disagreement I just meant to add a bit extra on to your post

But back to my initial point, in a situation like some of the runs, especially the last few GFS runs, the background synoptic pattern, including height falls and a strong low as you say, with sufficient moisture, do have a naturally pretty significant parameter space. Yet having no/very little solar heating can really limit CAPE, and while you are right it is definitely not essential as CAPE is not just about surface temp etc, that extra heating can lead to that 1500-2000j/kg of CAPE which makes an event a lot worse especially with the stronger wind shear. And While I'm sure that if current GFS runs verified perfectly there would be a significant QLCS at least, it realistically wouldn't be bad as if all that happened during peak heating.

But as you say just because an event doesn't reach its peak potential doesn't mean its not significant, and as both you and I have been saying these long range events are bound to change in timing - hence why I haven't been making a big thing of this timing issue and only mentioning it as a bit of side note being one of the only main limiting factors I see at this stage if some of the GFS runs were to verify.

And a small side note: Going by some ensembles and trends, I wouldn't even be *too* surprised to see the main focus of this event possibly shifting to the evening of the 2nd, though that isnt supposed to be any sort of forecast haha

For sure, it could effect Georgia and portions of the Carolinas the most. Somewhere in the southeast will likely see some bad weather; Not exactly sure where. but I'm gunna stick on middle ground right through the bootheel and Memphis as the middle of both ensembles

 

[UncleJuJu98]

Good golly lol seems like the GFS showing broken convection from missippi to Georgia as it moves east on the semi broken line. 850mb vertical vorticity lines up with simulated maybe this is a hint at supercells along a broken line. *Seems like winds aren't backed much though so it might not be a heightened tornado threat at some points.*

Vertical vorticity at 850mb is good to tell wether something is possibly supercellular if it lines up with simulated radar.

Elevated and not backed in the low levels probably because of a the elongated low.

 

[UK_EF4]

This is a sounding I pulled from S Arkansas on the 18z GFS at 00z. This is what I meant when I said possibly focus of event could shift to include the 2nd as well - but at least on this particular GFS run we could be dealing with a bimodal threat of initially supercells and also a QLCS. Either way too far out for details, and this post is mainly just for 'fun' (event tracking and to look back on purposes) rather than a forecast or to raise alarm bells, but the synoptic pattern is favourable for significant severe nevertheless.

 

[CheeselandSkies]

Yeah, the 18Z GFS would suggest a significant severe threat potentially from roughly I-45 in TX to I-55 in MS (pending possible capping issues apparent on soundings in some areas) on the afternoon/evening of the 2nd, then it's incredible how much the system speeds up overnight...now has the front entirely off the east coast by 00Z 3/4.

By comparison, the core of the threat area on April 26, 2011 was from E TX to LA, then the famous event in E MS/AL/E TN/NW GA on the 27th. That's about what you'd expect for a more typical west to east progression of one of these setups in a 24 hour period.

 

[UncleJuJu98]

Yeah, the 18Z GFS would suggest a significant severe threat potentially from roughly I-45 in TX to I-55 in MS (pending possible capping issues apparent on soundings in some areas) on the afternoon/evening of the 2nd, then it's incredible how much the system speeds up overnight...now has the front entirely off the east coast by 00Z 3/4.

By comparison, the core of the threat area on April 26, 2011 was from E TX to LA, then the famous event in E MS/AL/E TN/NW GA on the 27th. That's about what you'd expect for a more typical west to east progression of one of these setups in a 24 hour period.

GFS wants to do a big ole risk area west to east like easter 2020 lol.

 

[KevinH]

Posting this here in case people did not know and can go VOTE:

PLEASE READ - Vote on a new policy concerning severe weather threads

Good day everyone. In the past few weeks, we tested a new concept of allowing long-term threads for multiple events (i.e. last half of April). Several of you have spoken out against this with some very valid reasons around being able to go back and find information from an event quickly...

talkweather.com

 

[Taylor Campbell]

The last several runs of the GFS have certainly not tone down this threat. Especially the threat level change for Thursday. Widespread instances of extreme severe from the Mid South to the East Coast.