Severe WX March 29-30, 2022 Severe Event

[DetectiveWX]

Not to draw comparisions and criticism, but I'm getting the April 4-5, 2011 vibes or more recently the Dec 15 derecho outbreak.

 

[CheeselandSkies]

Speaking on the tornado threat only, I've got a bad feeling that we will see a bad tornado come out of the southern more semi-discrete mode, especially late in the evening in the Mobile and Florida Panhandle region as broken supercells and a semi-discrete mode are expected to interact with better wind shear and kinematic support as the night goes on. There will undoubtedly be multiple spin-ups within the line, but those will probably be very hard to track and see.

HRRR has certainly been...disconcerting in that regard. 00Z run held serve with that look.

 

[MikeP]

Correct me if I'm wrong, but tomorrow seems like it might be very unfortunate for many (at least with power outages). The ground is already quite saturated. Tree root systems are already compromised as a result. Gradient winds, if verified could be a huge problem with regard to tree/power line damage before the main line even arrives. Not feeling too good about it really. Take the T-storm warnings even more seriously tomorrow. Hurricane force winds suck....

 

[Clancy]

00Z HRRR seemed to pull some UH further east than last run.

 

[warneagle]

HRRR has certainly been...disconcerting in that regard. 00Z run held serve with that look.

Yeah we kind of got some of that in the same area with the last system, which is what produced the New Orleans tornado. If we get that kind of broken line structure like that again, it could be even worse given the wind fields. Obviously this system is going to be a big problem regardless due to the straight-line wind damage potential, but the idea of getting semi-discrete storms going in the presence of these dynamics is not a pleasant one to contemplate.

 

[Austin Dawg]

00Z HRRR seemed to pull some UH further east than last run.View attachment 12955

The NAM hodos for LA has been disturbing for tomorrow

 

[brianc33710]

So would NWS offices issue tornado warnings for thunderstorms with 80+ mph winds? James Spann is harping to treat tstm warns like tornadoes Wed nite.

 

[Fred Gossage]

So would NWS offices issue tornado warnings for thunderstorms with 80+ mph winds? James Spann is harping to treat tstm warns like tornadoes Wed nite.

No, these would still be severe thunderstorm warnings. However, if a severe thunderstorm warning is tagged for 80 mph winds, it now triggers the wireless emergency alerts on mobile devices. Many EMA offices and city/county officials will also sound sirens in cases like that.

 

[Blizzard1]

No, these would still be severe thunderstorm warnings. However, if a severe thunderstorm warning is tagged for 80 mph winds, it now triggers the wireless emergency alerts on mobile devices. Many EMA offices and city/county officials will also sound sirens in cases like that.

Yes I was about to say the same thing and I do recall Svr Tstorm Warnings triggering alerts when winds get to certain epic levels in the past.

 

[Fred Gossage]

Yes I was about to say the same thing and I do recall Svr Tstorm Warnings triggering alerts when winds get to certain epic levels in the past.

This is actually a new thing that has just recently started (first made official back in the summer), with the inclusion of tiered impact tags to severe thunderstorm warnings. When a severe thunderstorm warning gets a "destructive" impact tag in the text, either for 80+ mph winds or baseball or larger hail, wireless emergency alerts will now get triggered.

New “Destructive” Severe Thunderstorm Warning category to trigger Wireless Emergency Alerts on mobile phones

www.weather.gov

 

[Equus]

Moderate maintained on new D1; significant expansion of 15 hatch tornado risk, interestingly enough

 

[CheeselandSkies]

Some pretty ominous wording here. Seems like the linear forcing won't be as big a deterrent to isolated supercells as previously thought, at least in SPC's opinion:

...Parts of eastern LA...much of MS...AL...FL Panhandle...
Southern portions of the front/dryline will move much slower
compared to farther north, resulting in a longer duration of
boundary-layer moistening. A line of convection should become
evident by 21Z from southwest MS into parts of southern LA, moving
across MS and into north-central AL by about 03Z. The subtle lift,
combined with ample low-level moisture beneath an intense low-level
jet, will favor tornadic supercells which may peak during the night.
Effective SRH will remain high, averaging 400-500 m2/s2, with proper
hodograph elongation in the mid and high levels. Given the long
duration and slow eastward movement of this line of supercells, and
the magnitude of the forecast hodographs, a few intense tornadoes
could occur. However, the threat will become limited late in the
period due to decreasing instability to the east of about longitude
86W.

 

[JBishopwx]

High Wind Warnings are in effect for much of Mississippi and western Alabama until this evening.

 

[WesL]

Well good morning from Springdale, AR….

 

[brianc33710]

This is actually a new thing that has just recently started (first made official back in the summer), with the inclusion of tiered impact tags to severe thunderstorm warnings. When a severe thunderstorm warning gets a "destructive" impact tag in the text, either for 80+ mph winds or baseball or larger hail, wireless emergency alerts will now get triggered.

New “Destructive” Severe Thunderstorm Warning category to trigger Wireless Emergency Alerts on mobile phones

www.weather.gov

Great! I had actually asked about severe storm "levels" at Basic Skywarn Training last week (advanced was last night, great timing) & there are 3 not just 2. So all EMAs follow the 80+ mph wind/2.75" hail emergency rules. Baseball size hail probably won't be a problem this go round though. I had asked/wondered about a PDS Severe Thunderstorm Watch for this system as the wind threat is there. But given the likelihood of embedded tornadoes that might not work. The last PDS tstm watch had 95/90 wind threats but just 20/20 tornadoes. 95/90 winds but with 50 torn probs is more likely today-tonight. Could/Would the SPC issue a PDS Tornado watch but for straight line winds & not tornadoes?

 

[brianc33710]

Moderate maintained on new D1; significant expansion of 15 hatch tornado risk, interestingly enough

View attachment 12956

Yeah I thought that the SPC might expand Moderate a little further east. Birmingham is basically there (west Jeffco & Bessemer is) but I thought at least to Pell City & Sylacauga would go Mod. The SPC has split Jeffco AL a lot lately. I guess by now we know that they won't go High for just extreme straight line winds threats today & tonight.

 

[CheeselandSkies]

HRRR is pretty consistent on the idea that the New Orleans area north/west to Baton Rouge needs to be on their toes again today.

 

[Richardjacks]

I am late to the party on this one but sure looks like a very active afternoon and evening. Typically in these setups a bow/comma head forms and creates the highest straight line winds, but today it could have a lewp appearance and even tornado threat. That comma head/lewp could form fairly late near Al/Ms border or east and really accelerate eastward and I could see it targeting the Bham metro area. This would be seperate from the tornado risk further south.

 

[Blizzard1]

This is actually a new thing that has just recently started (first made official back in the summer), with the inclusion of tiered impact tags to severe thunderstorm warnings. When a severe thunderstorm warning gets a "destructive" impact tag in the text, either for 80+ mph winds or baseball or larger hail, wireless emergency alerts will now get triggered.

New “Destructive” Severe Thunderstorm Warning category to trigger Wireless Emergency Alerts on mobile phones

www.weather.gov

Without a doubt I know the alerts coming out on cell phones are newer so to say, I guess I’m referring to earlier days when there was a time or two they did the whole tornado sirens procedure when it was “just” a high end severe thunderstorm with high winds. I recall there even being a debate on when to go there with tstorm winds alone but this was years ago.

 

[Marshal79344]

The more I look at southern, more coastal Dixie Alley, the more I get concerned about big tornadoes there tonight.