Severe Event March 25th 2021

[Snowstorm920]

In typical HRRR fashion its pretty crazy in the warm sector Thursday

 

 

[WhirlingWx]

So, about the 3km NAM...

[jojo762]

Pending 00z CAM output, it seems quite possible that a rare D2 high risk is going to be in the cards.. Environment will be absolutely primed over a substantial area. Personally i'd probably pull the trigger for parts of Mississippi and Alabama, as long as CAMs do not show a boatload of junk in the warm sector (which is ultimately the main failure mode with this setup given the lack of CINH and large CAPE values).

[hlcater]

They wont do a D2 high at 06z. Not coming up from a D3 ENH. My guess is D2 MDT with a mention of an upgrade in later outlooks

[Bob's Burgers]

The nam3k simulated reflectivity goes absolutely HAM. Usually it gives up on convection and forms a line...the 18z run... not so much. 

[ATDoel]

8 minutes ago, hlcater said:

They wont do a D2 high at 06z. Not coming up from a D3 ENH. My guess is D2 MDT with a mention of an upgrade in later outlooks

Do they ever do a D2 high?  I don't think I've ever seen one.

[hlcater]

2 minutes ago, ATDoel said:

Do they ever do a D2 high?  I don't think I've ever seen one.

4/14/12 is the example that comes to mind

There is no such thing as a D3 high though

[DanLarsen34]

They’ve only issued a high risk in a day 2 outlook twice: 4-14-12, and 4-7-06. 

 

Given some of the discussion that I’ve seen from emergency management planners over social media today that surrounds the planning surrounding events like this, it might make sense for them to consider doing so this time, especially since the models are converging on a high impact, potentially life threatening scenario across the Deep South. 
 

At a minimum, I would expect to see a moderate risk with a strongly worded discussion mentioning the potential for long-track, violent tornadoes if the model runs continue to show a similar set-up to what they’ve been suggesting so far. 

24 minutes ago, hlcater said:

4/14/12 is the example that comes to mind

There is no such thing as a D3 high though

 

[KoalaBeer]

7 minutes ago, DanLarsen34 said:

They’ve only issued a high risk in a day 2 outlook twice: 4-14-12, and 4-7-06. 

 

Given some of the discussion that I’ve seen from emergency management planners over social media today that surrounds the planning surrounding events like this, it might make sense for them to consider doing so this time, especially since the models are converging on a high impact, potentially life threatening scenario across the Deep South. 
 

At a minimum, I would expect to see a moderate risk with a strongly worded discussion mentioning the potential for long-track, violent tornadoes if the model runs continue to show a similar set-up to what they’ve been suggesting so far. 

 

My only gripe with this (no matter if you fall on the more conservative or aggressive side of this forecast) is the absolutely absurd scale in place. What percentage of the population is looking at the discussion compared to just looking at the overall rating? The SPC shouldn’t have to issue a high risk to convey the risk at D2 but I think maybe they should because saying “moderate” doesn’t concern the ceiling of this outbreak at all. Why write in “violent long track tornadoes are possible” if we are just going to say mehhh, this is moderate aka literally meaning average.....

[CryHavoc]

11 minutes ago, KoalaBeer said:

My only gripe with this (no matter if you fall on the more conservative or aggressive side of this forecast) is the absolutely absurd scale in place. What percentage of the population is looking at the discussion compared to just looking at the overall rating? The SPC shouldn’t have to issue a high risk to convey the risk at D2 but I think maybe they should because saying “moderate” doesn’t concern the ceiling of this outbreak at all. Why write in “violent long track tornadoes are possible” if we are just going to say mehhh, this is moderate aka literally meaning average.....

MDT risks are quite rare, esp for D2, and mean anything but average.  MDT risks are enough for local weathermen to start talking about a big weather day, which usually alerts most people to the fact that the day could be really rough.

[KoalaBeer]

8 minutes ago, CryHavoc said:

MDT risks are quite rare, esp for D2, and mean anything but average.

I’m well aware of that, but does that convey the right message to anyone but weather nerds or meteorologists? Does the general public really look at a D2 MOD outlook and say “Shit this could be a really bad time tomorrow?” Talking with my friends and family that’s a huge no. But I’m born and raised in the northeast, perhaps I underestimate the weather folks are prepared for in the Deep South. 

Edit: I feel like these people are also relying on local media instead of the SPC as well, which honestly might be a good thing.

[David Reimer]

I see the hype train is full speed ahead this afternoon. There remain a few ways Thursday's tornado threat could be dampened. Widespread warm sector precipitation thanks to the lack of a stronger EML, a mixed convective mode, etc. Let's see what the 12Z guidance looks like before we all start screaming 'DAY TWO HIGH RISK LIKELY! OMGGGGGGGGGGGG'. Heck, let's see what this evening's 0Z guidance shows. If the Euro, GFS, the HREF, and each of their respective ensemble majorities end up converging on an 'outbreak' solution? Sure, I could see a high risk showing up by Thursday. Does it really matter? No.

[CryHavoc]

17 minutes ago, KoalaBeer said:

I’m well aware of that, but does that convey the right message to anyone but weather nerds or meteorologists? Does the general public really look at a D2 MOD outlook and say “Shit this could be a really bad time tomorrow?” Talking with my friends and family that’s a huge no. But I’m born and raised in the northeast, perhaps I underestimate the weather folks are prepared for in the Deep South. 

Edit: I feel like these people are also relying on local media instead of the SPC as well, which honestly might be a good thing.

Most people do not even know what the SPC is.  And most of those that do are not poring over charts to discern the differences between ENH/MDT/HIGH.  We're in the niche of niches here.

So yeah, while to the average layperson a "Moderate" risk might not sound threatening, I doubt many of them are looking at advanced modeling to determine exactly what that means.  They turn on the weather, see the Mets on TV with their coats off and their serious face on, uttering words like "Potentially historic" or "a long day ahead for much of the viewing area, keep your weather radios on" and assume that things could get really nasty.

 

  

13 minutes ago, David Reimer said:

I see the hype train is full speed ahead this afternoon. There remain a few ways Thursday's tornado threat could be dampened. Widespread warm sector precipitation thanks to the lack of a stronger EML, a mixed convective mode, etc. Let's see what the 12Z guidance looks like before we all start screaming 'DAY TWO HIGH RISK LIKELY! OMGGGGGGGGGGGG'. Heck, let's see what this evening's 0Z guidance shows. If the Euro, GFS, the HREF, and each of their respective ensemble majorities end up converging on an 'outbreak' solution? Sure, I could see a high risk showing up by Thursday. Does it really matter? No.

Jojo is not the type to be overly bullish without reason IMO.   I think they're just pointing out that the ceiling here, if the SPC sees things resolving at the right time and place, is a Day 2 high.  Heck, we might not even have a Day 2 MDT tomorrow (although I think that's much more likely).

[mob1]

If Globals are correct, it might not matter as much if things initiate  a bit early as the storm is much more impressive synoptically than what the mesoscale models have. Euro and GFS have a rather impressive deepening LP  (sub 990 on the Euro and just a tad higher on the GFS) with some pretty insane upper and mid level winds in the warm sector.  

[JasonOH]

There’s a lack of an EML which is usually a sign for me of messy storm mode when it comes to Dixie. Don’t expect a D2 high. 

[KoalaBeer]

17 minutes ago, CryHavoc said:

Most people do not even know what the SPC is.  And most of those that do are not poring over charts to discern the differences between ENH/MDT/HIGH.  We're in the niche of niches here.

So yeah, while to the average layperson a "Moderate" risk might not sound threatening, I doubt many of them are looking at advanced modeling to determine exactly what that means.  They turn on the weather, see the Mets on TV with their coats off and their serious face on, uttering words like "Potentially historic" or "a long day ahead for much of the viewing area, keep your weather radios on" and assume that things could get really nasty.

 

  

Jojo is not the type to be overly bullish without reason IMO.   I think they're just pointing out that the ceiling here, if the SPC sees things resolving at the right time and place, is a Day 2 high.  Heck, we might not even have a Day 2 MDT tomorrow (although I think that's much more likely).

Great points havoc and great conversation, it’s why I love this forum. I would say most people would recognize the SPC maps even if they don’t know the agency by name, maybe that’s a different problem in itself. We are definitely in the niche here and sometimes that’s hard to remember. TV Mets like Spann do a phenomal job putting it into layman’s terms. Having said that I’d still love to see a change up of how the SPC issues it’s enh/mod/high outlooks. About to join a long conference call for work so I’ll have to take off for a while but I hope to hear more suggestions. 

[Bob's Burgers]

Drop the term Moderate. Actually, just drop all the wording together and do a numbered scale 1/5, 2/5... etc. 

[JasonOH]

FWIW the whole SPC thing isn’t even meant for the general public at all. It’s guidance mainly for mets and to a lesser extent, emergency management (controls staffing levels).  It wasn’t designed for general consumption but it’s gone that way over time. The good thing is that lots of TV mets use the 1-5 scale to communicate it.

[Santa Clause]

Storm mode looks very problematic for TOR. Expect ENH or MDT.

[mob1]

7 minutes ago, JasonOH said:

FWIW the whole SPC thing isn’t even meant for the general public at all. It’s guidance mainly for mets and to a lesser extent, emergency management (controls staffing levels).  It wasn’t designed for general consumption but it’s gone that way over time. The good thing is that lots of TV mets use the 1-5 scale to communicate it.

During last week's event, I kept seeing things like "level 4 severe weather event" and had no clue what it was. It's actually a really good system, numbers speak to people. 

[Bob's Burgers]

10 minutes ago, JasonOH said:

FWIW the whole SPC thing isn’t even meant for the general public at all. It’s guidance mainly for mets and to a lesser extent, emergency management (controls staffing levels).  It wasn’t designed for general consumption but it’s gone that way over time. The good thing is that lots of TV mets use the 1-5 scale to communicate it.

Should the SPC evolve the convective outlook in response to the public consuming their products? To me it would make sense for the sake of better hazard communications. 

[hlcater]

32 minutes ago, JasonOH said:

There’s a lack of an EML which is usually a sign for me of messy storm mode when it comes to Dixie. Don’t expect a D2 high. 

I'm not entirely sure what you're seeing. EML is present and accounted for on much of guidance at 15z. Using the HRRR for visualization.

 

[nwohweather]

Insane pattern we’re in here folks. After getting 33 tornadoes last week in one day (absolutely a High risk verified) we’re now looking at potentially another in the same spot? Wild

[jojo762]

2 hours ago, jojo762 said:

Pending 00z CAM output, it seems quite possible that a rare D2 high risk is going to be in the cards.. Environment will be absolutely primed over a substantial area. Personally i'd probably pull the trigger for parts of Mississippi and Alabama, as long as CAMs do not show a boatload of junk in the warm sector (which is ultimately the main failure mode with this setup given the lack of CINH and large CAPE values).

Just to simmer down the controversy, or perhaps explain myself better, I emphasized important parts of my post that appear to maybe have gotten entirely overlooked in lieu of the High Risk mention.

For everyone that is being bearish, its very hard to ignore when the NAM, NAM NEST, GFS, EURO, UKMET, Canadian, etc. (literally all guidance available) shows a top tier parameter space in place. 18z NAM NEST (typically runs toward linear/messy solutions, as we all know too well) featured what would likely be a tornado outbreak with a variety of semi-discrete to discrete convection across the warm sector throughout the day. Guess we'll see what the other CAMs have to say soon, but to see the NAM NEST doing that is quite concerning. I see a similar convective evolution to what we had last Wednesday, albeit with likely more intense supercells than we had then due to a more substantial forecast parameter space (both with kinematics and thermodynamics). Cautious pessimism is almost always good, especially when it comes to concerns about lack of a cap in the south, but guidance just does not indicate that is all that much to worry about right now wrt tornado potential.

[brianc33710]

Spann generally says a #/5 level threat. Moderate doesn't sound scary but a 4/5 level gets the public's attention.

[Bob's Burgers]

1 minute ago, brianc33710 said:

Spann generally says a #/5 level threat. Moderate doesn't sound scary but a 4/5 level gets the public's attention.

 

[CheeselandSkies]

Thursday's gonna be another one of those "respect the polygon" days...
 

 

[JasonOH]

1 hour ago, hlcater said:

I'm not entirely sure what you're seeing. EML is present and accounted for on much of guidance at 15z. Using the HRRR for visualization.

 

I should have clarified more. The EML is not enough (at least on the soundings I’ve grabbed) to provide substantial capping.  The EML isn’t quite warm enough at its base

[Bob's Burgers]

16 minutes ago, CheeselandSkies said:

Thursday's gonna be another one of those "respect the polygon" days...
 

 

This is gold

[jpeters3]

2 hours ago, JasonOH said:

There’s a lack of an EML which is usually a sign for me of messy storm mode when it comes to Dixie. Don’t expect a D2 high. 

This ^^^^^

In general, I don't think issuing day 2 High risks is a good idea.  Especially in the SEUS where there is always the inherent uncertainty regarding storm mode.  So I would argue that a a day 2 High would be an irresponsible move.

Obviously the ceiling on this event is very high. But there is still bust potential, as we have seen in the past with numerous would-be SEUS events.  Parameter space is never the entire story.