Severe WX Severe Threat 17-18 March 2021

[The Nino]

I really don't know what people expect. Models are models based upon endless variables and are a statistical approach to predicting reality. The job of the SPC or mets are to relay there being an increased probability of an outcome. The only fools are the ones who take these predictions as predetermined reality.

 

[Equus]

I do not trust QLCS in Dixie, never, not at all. Never. We get a ridiculous percentage of our tornadoes here, even strong ones, from nocturnal QLCS, and in a setup this dynamic if the LLJ has started is just asking for trouble. Hopefully it'll stay tame but there's definitely that risk.

 

[Chris3024]

looks like a meso low up near aberdeen

 

[Clancy]

It looks like SPC just pushed out a new D1 outlook. Can't see the changes yet, though.

 

[Evan]

We shouldn't forget about the possibility of localized nocturnal flash-flooding. Even though the line is moving faster than expected there's been some torrential rain in many areas today with more on the way.

 

[Tennie]

Several flash flood warnings around Alabama and Mississippi this evening due to the heavy rain.

Oh boy, just wait for those times when the Tornado and Flash Flood Warnings overlap...

 

[sak]

Natural selection will eventually take care of stupidity.

Meanwhile, I'll be glad a violent tornado didn't sweep away my house (so far) and be able to sleep peacefully for the first time since this event came onto the mid range guidance. Big relief. I feel like there wouldn't be this many (incorrect) bust calls if this had stayed a moderate and the central MS portion wasn't included.

I'm not sure that anyone is really saying it was a "bust" on the technical outcome. But it is definitely busting in terms of overall outbreak violence. Dozens of tornado reports mean it didn't bust, but if someone told you we'd have less than 5 EF3s (or, less than say, 50 miles of EF3 tornado damage paths... as it is entirely possible some storms dropped 2 or 3 or even more EF2s/EF3s in fairly quick succession as the storms seemed to cycle quite a bit today) which seems pretty likely at this point, I think you would call that at least a little surprising.

I don't think it's fair to sit here and criticize and dismiss people who expressed some level of skepticism 4-6 hours ago based on how it was unfolding in LA/ARK/W MS, and the junk convection that was effecting northern AL. Seemed like some pretty reasonable nowcasting to be quite honest.

 

[WhirlingWx]

DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0744 PM CDT WED MAR 17 2021

VALID 180100Z - 181200Z

...THERE IS A HIGH RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF
ALABAMA...

..SUMMARY

THE POTENTIAL FOR SIGNIFICANT TORNADOES CONTINUES TONIGHT. MUCH OF
THE GREATEST RISK IS OVER ALABAMA.

..01Z UPDATE

LLJ IS STRENGTHENING ACROSS THE CENTRAL GULF STATES THIS EVENING
AHEAD OF A STRONG MID-LEVEL SHORT-WAVE TROUGH THAT IS PROGRESSING
INTO THE LOWER MS VALLEY. LARGE-SCALE FORCING APPEARS TO BE
CONTRIBUTING TO AN ELONGATED MCS THAT IS GROWING UPSCALE FROM
EASTERN MS INTO SOUTHEASTERN LA. WHILE THIS MCS IS GRADUALLY
MATURING, NUMEROUS EMBEDDED MESOS ARE NOTED ALONG THIS CORRIDOR AND
THE STRENGTH OF THE WIND FIELDS CONTINUE TO FAVOR THE POTENTIAL FOR
SUPERCELLS. OF MORE CONCERN ARE THE DISCRETE STORMS THAT CONTINUE
AHEAD OF THE MCS, AND THE POTENTIAL FOR NEW SUPERCELLS.
STRENGTHENING WIND FIELDS FAVOR TORNADOES WITH THIS ACTIVITY. THE
PRIMARY CHANGES AT 01Z ARE TO LOWER SEVERE PROBABILITIES IN THE WAKE
OF THE EVOLVING MCS.

..DARROW.. 03/18/2021

 

[speedbump305]

I’m just gonna sum up the outbreak. We have a high risk. Several tornadoes have touched down and have reported to have done damage. It hasn’t really been a bust, we still have one more round, and another outbreak is possible tomorrow. Mississippi has kinda busted, but the storms earlier packed a punch in mississippi. But anyways, we will just have to wait and see just how bad the outbreak was

 

[Clancy]

High Risk stays.

 

[MattPetrulli]

Is that an mcv north of meridian?

Probably gonna need a tornado warning on that soon given radar trends. Pretty sure this is the cell with the intense UH track projected by 23z HRRR

 

[Equus]

I'm not sure that anyone is really saying it was a "bust" on the technical outcome. But it is definitely busting in terms of overall outbreak violence. Dozens of tornado reports mean it didn't bust, but if someone told you we'd have less than 5 EF3s which seems pretty likely at this point, I think you would call that at least a little surprising.

I don't think it's fair to sit here and criticize and dismiss people who expressed some level of skepticism 4-6 hours ago based on how it was unfolding in LA/ARK/W MS, and the junk convection that was effecting northern AL. Seemed like some pretty reasonable nowcasting to be quite honest.

Oh it's definitely underperformed compared to the higher ceiling potential, we probably didn't get a single violent or long tracked tornado; I think it classifies as verification regardless due to the quantity of tornadoes and the fact that some were pretty strong. I can totally see where the bust calls come from as today never got higher than 66 here thus far with heavy rain but take that monster wedge that crossed the state line in SW AL and place it over, say, downtown Birmingham and people would be singing a different tune.

 

[Clancy]

Tornado probs are now max 30%. They still seem confident in more tornadoes through tonight.

 

[GA Stormchaser]

Tornado Warning for cell about to enter AL (Dekalb Co MS), and I suspect the lead cell north of Livingston will go tornado warned soon also. TWINS...heading towards Tuscaloosa.

 

[TuscWeathergrl]

It’s a tale as old as time here.

That’s sad. And unnecessary. There’s a difference between being fascinated by meteorology and wishing death and destruction on people.

 

[KevinH]

DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0744 PM CDT WED MAR 17 2021

VALID 180100Z - 181200Z

...THERE IS A HIGH RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF
ALABAMA...

..SUMMARY

THE POTENTIAL FOR SIGNIFICANT TORNADOES CONTINUES TONIGHT. MUCH OF
THE GREATEST RISK IS OVER ALABAMA.

..01Z UPDATE

LLJ IS STRENGTHENING ACROSS THE CENTRAL GULF STATES THIS EVENING
AHEAD OF A STRONG MID-LEVEL SHORT-WAVE TROUGH THAT IS PROGRESSING
INTO THE LOWER MS VALLEY. LARGE-SCALE FORCING APPEARS TO BE
CONTRIBUTING TO AN ELONGATED MCS THAT IS GROWING UPSCALE FROM
EASTERN MS INTO SOUTHEASTERN LA. WHILE THIS MCS IS GRADUALLY
MATURING, NUMEROUS EMBEDDED MESOS ARE NOTED ALONG THIS CORRIDOR AND
THE STRENGTH OF THE WIND FIELDS CONTINUE TO FAVOR THE POTENTIAL FOR
SUPERCELLS. OF MORE CONCERN ARE THE DISCRETE STORMS THAT CONTINUE
AHEAD OF THE MCS, AND THE POTENTIAL FOR NEW SUPERCELLS.
STRENGTHENING WIND FIELDS FAVOR TORNADOES WITH THIS ACTIVITY. THE
PRIMARY CHANGES AT 01Z ARE TO LOWER SEVERE PROBABILITIES IN THE WAKE
OF THE EVOLVING MCS.

..DARROW.. 03/18/2021

How do you see this before it is even updated on the SPC website? LOL

 

[Richardjacks]

I fear this is about to get very serious. I am familiar with this look.

 

[Evan]

How do you see this before it is even updated on the SPC website? LOL

One option is:

SPC Products Page

 

[KevinH]

I fear this is about to get very serious. I am familiar with this look.

@Richardjacks please elaborate?

 

[CheeselandSkies]

Meso near Gainsville, AL sure could use at least a SVR.