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Severe WX Severe Threat 17-18 March 2021

A Vague Planet said:
Hey all, LONG time lurker here. Thought I'd finally saddle up and create an account. Not so much to contribute to any in depth analysis. More so to offer my services as an amateur weather observation location if you can call it that. I don't imagine that TalkWeather has a lot of coverage in the Carolinas so I'd be more than happy to offer my services letting you guys know conditions on the ground here in the Charlotte, NC area, especially since the Day 4 Outlook might throw some stuff my way. Any other time of the year when we have events I'd be happy to report conditions here as well. Thanks so much to all of you for increasing my weather knowledge over the years. It's been a great ride.
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Glad to have you!! @Tyler Penland is from over that neck of the woods as well!
 
I say the following while acknowledging that the ingredients are still there for a significant event. The 00z HRRR really goes bonkers with what looks like quite a bit of mature convection over the warm sector starting in the early afternoon, even if it's a little messy. However, 0-1 km SRH is under 200 m2/s2 for a lot of the area until the end of the run. I'm not saying this to downplay the threat, but I'm wondering if that could limit the higher-end ceiling of this event *until at least the evening/overnight round*, or if the higher-end thermodynamics and instability for the area could compensate. Or conversely, does anyone think that the wind fields and shear will just straight up be stronger than shown by the HRRR? I'm more used to Plains events having the instability and lacking huge shear, not really familiar with Dixie Alley climo in these circumstances, and I'm not an expert by any means.

Again, I stress that I'm not trying to make anyone put their guard down, because that run is still awfully worrisome. Just asking, because obviously a lot of the pretty high-end events (no, I'm not only referring to 4/27/11, of course) in the area that come to mind had notably more shear/SRH than this *one* run shows. I also insist that the end of the run brings more favorable shear across the threat area anyways, so even if storms in the afternoon don't materialize into widespread long-track sigtor producers, the later round still very well could have some, as this will likely be an event with several rounds, as has been widely discussed here already. Regardless, it would be best if the event weren't to verify to that extent.

EDIT: Oh well, another note, I should have thought this through more, but the afternoon part of the event is where boundaries left by earlier storms have a role, I would imagine. We could still have afternoon storms interact with boundaries that locally enhance the shear, even if widespread high helicity values aren't present.
 
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A Vague Planet said:
Hey all, LONG time lurker here. Thought I'd finally saddle up and create an account. Not so much to contribute to any in depth analysis. More so to offer my services as an amateur weather observation location if you can call it that. I don't imagine that TalkWeather has a lot of coverage in the Carolinas so I'd be more than happy to offer my services letting you guys know conditions on the ground here in the Charlotte, NC area, especially since the Day 4 Outlook might throw some stuff my way. Any other time of the year when we have events I'd be happy to report conditions here as well. Thanks so much to all of you for increasing my weather knowledge over the years. It's been a great ride.
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Welcome! Glad to have another Carolina resident, although I'm a bit NW of you up here outside Boone in snow miser country.
 
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WhirlingWx said:
I say the following while acknowledging that the ingredients are still there for a significant event. The 00z HRRR really goes bonkers with what looks like quite a bit of mature convection over the warm sector starting in the early afternoon, even if it's a little messy. However, 0-1 km SRH is under 200 m2/s2 for a lot of the area until the end of the run. I'm not saying this to downplay the threat, but I'm wondering if that could limit the higher-end ceiling of this event *until at least the evening/overnight round*, or if the higher-end thermodynamics and instability for the area could compensate. Or conversely, does anyone think that the wind fields and shear will just straight up be stronger than shown by the HRRR? I'm more used to Plains events having the instability and lacking huge shear, not really familiar with Dixie Alley climo in these circumstances, and I'm not an expert by any means.

Again, I stress that I'm not trying to make anyone put their guard down, because that run is still awfully worrisome. Just asking, because obviously a lot of the pretty high-end events (no, I'm not only referring to 4/27/11, of course) in the area that come to mind had notably more shear/SRH than this *one* run shows. I also insist that the end of the run brings more favorable shear across the threat area anyways, so even if storms in the afternoon don't materialize into widespread long-track sigtor producers, the later round still very well could have some, as this will likely be an event with several rounds, as has been widely discussed here already. Regardless, it would be best if the event weren't to verify to that extent.

EDIT: Oh well, another note, I should have thought this through more, but the afternoon part of the event is where boundaries left by earlier storms have a role, I would imagine. We could still have afternoon storms interact with boundaries that locally enhance the shear, even if widespread high helicity values aren't present.
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Yes, boundaries left by earlier convection with the crazy shear values moving in during the evening would likely spell real trouble.
 
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Clancy said:
18Z hi-res NAM wants to keep things out of NE Alabama and all of North Georgia (even as the night progresses). I'm certainly not smart enough to figure out where/why this may be right or wrong, so I'm curious what those on here think about it.
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Wedge aka cold air damming (CAD).
NAM is really holding the warm front up compared to some other models. Hard to argue against it historically but it's been really off it's game this winter so far (consistently too strong/deep with CAD) so I'm interested to see how this one plays out, particularly since there's not time for a strong high to build in between tomorrow's system and Wednesday. This one will rely more on the SE flow into the low and that gets tricky.
 
TuscWeathergrl said:
I’ve lurked for years but only post once in a blue moon because I have nothing educated and worth while to say. Just throwing out there that I’m in the Tuscaloosa tornado magnet area and will keep everyone updated on what I see here.
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Glad to have you!
 
I'm interested in seeing if the SPC will at least give us a "Moderate" Risk with this system. I'm not saying 'HIGH" because even last Easter was neglected a High risk designation.
 
TuscWeathergrl said:
Thank you!! I really wanted to be a meteorologist, sucked at math. So now I work in nursing and am a weather nerd instead. Also guys, all of the local meteorologists are doing frequent Facebook lives with forecast updates. Which obviously happens the most before a forecasted major event.
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Welcome! Fellow nurse and weather nerd here in Birmingham. You will really enjoy this forum. Sometimes over my head, but I am always learning!
 
Austin Dawg said:
I think that is the reason of many that love weather to not follow that path. Definitely true in my case.
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I am quite the opposite I have had College Algebra, Trigonometry Calculus I, II, and III, Statistics, and Calculus Based Statistics and still have a hard time understanding what you guys are talking about in this forum. I got an A in all of them math classes as well.
 
It's at the tail end of its range but the 00Z HRRR sim ref/UH already looks ominous. Scattered, widely spaced implied supercells in the open warm sector across MS/AL.

This could just be nitpicking but the hodographs on the 00Z NAM forecast soundings don't look quite as perfect to me as they did on the 12Z and 18Z runs. Still plenty favorable for tornadic supercells, though.
 
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I’ll be chasing Wednesday, for the first time in a while, not sure where to set up. Wondering if i should go for the storms that fire near central al, or head to west Mississippi
 
MAMASZ said:
Welcome! Fellow nurse and weather nerd here in Birmingham. You will really enjoy this forum. Sometimes over my head, but I am always learning!
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Sweet, more meteorology healthcare nerds!
A warm welcome from a Huntsville nurse & weather enthusiast. Happy to have y'all here!
 
Equus said:
I think 4/27 has wrecked the idea of what a normal high end outbreak is like. 4/28/14 and Easter Sunday last year were very large high end outbreaks overall and they're an order of magnitude less intense than 4/27/11. Sure we'll have another 4/27-esque event one day in the future but people expecting a dozen violent tornadoes are going to feel that, say, the three we had last April 12 was an underperforming event overall because it didn't match 4/27. Super Outbreaks are rare anomalies.
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Super Tuesday 2008, 4/10/09, 4/24/10, 4/15-16/11, 3/2/12, 11/17/13, etc. were also pretty high end outbreaks that have been overshadowed by 4/27/11. I think people should remember before 4/27, the previous outbreak with double-digit numbers of violent tornadoes was all the way back in 1974 (5/31/85 was *almost* a super outbreak imo, with 9 violent tornadoes, but that's still a 26-year gap).

I think I've made another post on this before, but adjusting for less stringent rating standards in the 60s and 70s, 4/27/11 might actually have had more violent tornadoes than any other recorded outbreak. Holding future outbreaks up to the standard of a possibly world record-breaking super outbreak isn't just an unfair comparison, it's also potentially dangerous. The last thing we want is people to think a tornado threat isn't serious because "it's not as bad as 4/27".
 
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