Severe WX Severe Weather Threat 3/14-3/16

[Bulkshear]

This post isn’t directed at you, but it made me think of this.

While it will be hard to match the sheer violence of an 1884/1932/1974/2011 type outbreak, Alabama did have its #1 (4/27/11), #2 (4/15/11), and #4 (4/28/14) largest outbreaks within the span of 1,100 ish days. I don’t know what my point is other than #2 and #4 aren’t remembered as vividly, but boy they sure did produce a lot of tornadoes in one day and they occurred relatively close in time.

This was simply all I was pointing out as well

 

[UncleJuJu98]

This post isn’t directed at you, but it made me think of this.

While it will be hard to match the sheer violence of an 1884/1932/1974/2011 type outbreak, Alabama did have its #1 (4/27/11), #2 (4/15/11), and #4 (4/28/14) largest outbreaks within the span of 1,100 ish days. I don’t know what my point is other than #2 and #4 aren’t remembered as vividly, but boy they sure did produce a lot of tornadoes in one day and they occurred relatively close in time.

Ah good point!

 

[KevinH]

Yeah, 18Z holds serve and if anything makes the threat for the Southeast worse. Just some absurdness going on.
View attachment 34823View attachment 34825View attachment 34826View attachment 34827

What in the WORLD?

 

[MichelleH]

If anyone wants to see what I consider to be the absolute apex of meteorological discussion: go check out the 4/27/11 thread on AmericanWX forums. Fred and two other Mets (CUMet and Baroclinic_Instability) give a masterclass on meteorological discussion as the model outputs come through leading up to the event. Fred pretty much nailed the event 3-4 days out, especially with 4/27 being the main event day.

He did here too. Sharing this in case any of the newer members haven't seen it. Full archived thread of the discussion leading up to and beyond of Voldemort.

Archive - Severe threat April 26-27, 2011

This thread is a real-time re-creation of the April 27, 2011 event thread. Posts in this thread will be made at the same date and time as the original thread in 2011. Replies will not be allowed in this thread, instead we ask that you use the April 27, 2011 discussion thread instead...

talkweather.com

 

[Bulkshear]

What in the WORLD?

It’s called bad news

 

[KevinH]

This is the 18z GFS sounding for Monroe County, MS for Saturday.

That OFF THE CHARTS hodo, and SRH

 

[ColdFront]

Correct me if this is incorrect but with that much shear couldn’t the updrafts get ripped apart since we are struggling with instability?

I wouldn’t necessarily say we are struggling with instability. Check out the 3/2/2012 outbreak for reference. While the supercells were pretty mature at that point, the 2 Eastern KY discrete cells were operating in some insane shear with very meager instability. I think it was close to 800+ SRH with only around 500 K/J of cape. Not to mention the nocturnal inversion was starting to cap things off. The west liberty EF3 was actually Kentucky’s longest tracked tornado until Mayfield

 

[tennessee storm chaser]

Would you extend that threat north into TN for the tornado threat specifically or do you think this will be more of an AL and MS event for tornadoes? What’s your thoughts on how far north this threat may go?

If euro and Ukie are correct it be big tornado outbreak for west most central Tennessee . Gfs would be further southeast some . But for this gfs run is a outlier

 

[UncleJuJu98]

I wouldn’t necessarily say we are struggling with instability. Check out the 3/2/2012 outbreak for reference. While the supercells were pretty mature at that point, the 2 Eastern KY discrete cells were operating in some insane shear with very meager instability. The west liberty EF3 was actually Kentucky’s longest tracked tornado until Mayfield

Yeah, some events tear them apart some don't. My preference would be too see 1500-2000j of cape to be sufficient for my liking.

 

[KevinH]

Just the consistency of it all. But I said major downtrend. As in, the event turning into basically nothing but another wind bag.
Right now its looking like a tornado outbreak.

Yeah I don’t think you are wrong…

Have much flip flopping have the models been doing about this event for the last two weeks? One week?

 

[Bulkshear]

Yeah, some events tear them apart some don't. My preference would be too see 1500-2000j of cape to be sufficient for my liking.

For that much of a sheared environment, absolutely

 

[JPWX]

Would you extend that threat north into TN for the tornado threat specifically or do you think this will be more of an AL and MS event for tornadoes? What’s your thoughts on how far north this threat may go?

I believe Tennessee gets in on this threat too but how much of a threat is the main question. Overall, this will be a regional wide outbreak meaning basically the entire Southeast Region and extending as far north as Indiana. SPC already has SE Iowa into Illinois in the Friday threat so there's no reason why Saturday's threat wouldn't extend east from there into Indiana/Ohio and vicinity.

 

[ColdFront]

Yeah, some events tear them apart some don't. My preference would be too see 1500-2000j of cape to be sufficient.

A lot of that is hard to model too. Even on 4/27/11 with its insane Cape values, you can see it took a few storms to actually merge their updrafts together to sustain themselves in the stronger shear areas. And a few tornados took a while to actually get fully condensed to the ground due to the insane low level shear if you see video of their beginning phases (Cullman especially, Hackleburg, Rainsville)

I’ve seen this happen in both set ups though. Sometimes they “topple over”, other times it fuels them

 

[UncleJuJu98]

I want to note as well, the huge sickle hodgraphs is favorable for stream wise vorticity. Your more favorable hodograph, not necessary but it's optimum, that hodograph from Mississippi that was shared earlier was very impressive.

 

[Justin Hindman]

I look at these models, but it’s all blank to me until it’s 24-48 hours out. Last three systems have been big hyped . This one does looks the strongest so far I will say

 

[wx_guy]

18z GFS some soundings:

1) Southeast LA at 18z Saturday --->








2) Near Jackson MS at 21Z on Satuday --->





3) 21Z Saturday near Tuscaloosa --->



And finally, 4) A BOX sounding of Western AL and Eastern MS (entire states from north to south)







Takeaways: Holy ****, SRH is off the charts, CAPE is higher than in recent events, 3CAPE of 50-150 is on the table, and just all around bad news. Of note, on the box sounding that encompasses a huge area, a) The SARS sounding analogs match 13 loose matches (enough to be statistically valid) and have a whopping 77% of those analogs producing tornadoes. That gives very high confidence of tornado events. and b) On all of these soundings, notice the box plots for STP ---> see how the line is near/crossing the horizontal line in the middle of the EF4+ box plot? That means of all EF4+ tornadoes that are recorded in the statistics for this box plot, the STP's depicted here are at/near/exceeding the STPs of those events in over half of the cases. The through line can't be understated: A high end tornado event is possible.

 

[tennessee storm chaser]

18z GFS some soundings:

1) Southeast LA at 18z Saturday --->


View attachment 34833





2) Near Jackson MS at 21Z on Satuday --->


View attachment 34834


3) 21Z Saturday near Tuscaloosa --->

View attachment 34835

And finally, 4) A BOX sounding of Western AL and Eastern MS (entire states from north to south)


View attachment 34836




Takeaways: Holy ****, SRH is off the charts, CAPE is higher than in recent events, 3CAPE of 50-150 is on the table, and just all around bad news. Of note, on the box sounding that encompasses a huge area, a) The SARS sounding analogs match 13 loose matches (enough to be statistically valid) and have a whopping 77% of those analogs producing tornadoes. That gives very high confidence of tornado events. and b) On all of these soundings, notice the box plots for STP ---> see how the line is near/crossing the horizontal line in the middle of the EF4+ box plot? That means of all EF4+ tornadoes that are recorded in the statistics for this box plot, the STP's depicted here are at/near/exceeding the STPs of those events in over half of the cases. The through line can't be understated: A high end tornado event is possible.

These hodos are based off the 18z gfs correct ?

 

[Bulkshear]

I look at these models, but it’s all blank to me until it’s 24-48 hours out. Last three systems have been big hyped . This one does looks the strongest so far I will say

This one also correlates with a TNI above 2! You also have this storm happening in the correct phase too, well this only matters if you think ENSO heavily dictates major outbreaks.

 

[wx_guy]

These hodos are based off the 18z gfs correct ?

All are 18z GFS yep

 

[KevinH]

Nah this event won't compare, lot more pieces that would need to come together. This event could be dangerous but you probably won't see another April 27th until about 2040-2050 I would guess.

You are going to end up eating your words

Super Outbreaks only happening once every 35-40 years is no longer the case. Not saying this weekend will be a Super Outbreak, but we will see one well before 2040