StormySquares

Well I think we found the ceiling 

Just now, jpeters3 said:

NAM nest remains stubbornly devoid of convection through much of the warm sector.  However, there do appear more discrete cells close to the triple point than in previous runs.

Would that clearing in MS between 21 and 00z be where discrete cells form? Maybe it's just not picking it up, it's happened before.

1 minute ago, Upper Level LOL said:

Good thread by good follow Tony Lyza on questions about the latest NAM run not initiating isolated supercellular convection. The start of the thread is here:

 

 

Just about to post this. Very good write up, worth a read.

3 minutes ago, jpeters3 said:

IMO, there are still a lot of question marks here.  I think MOD day 3 was a good call by SPC given the potential upper envelope, but if other CAMS show similar trends to the NAM NEST, we won't see an upgrade to HIGH tomorrow.

Isn't linear solutions a bias the 3KMNAM has? Should it be taken with a grain of salt?

1 hour ago, jaxjagman said:

Yeah but with the virus on-going and the stay at home policy ,people living in mobile homes will be  more vulnerable unless you lift the ban so they can seek shelter.Not a good situation to be in right now

I can't imagine the travel ban extends to people who live in mobile homes if a tornado is coming at them. Or why you would yield to the ban in the first place in such an event.

It's probably fair to say it looks similar to 4/27/11 synoptically but that certainly doesn't equal the same outcome. 

2 minutes ago, Quincy said:

Want to try to not get too specific on details this far out, but the synoptic signal is there for a potentially higher-end event. There are some key differences, but 4/27/11 is ranking as a relatively close analog at this stage. 

Speaking of details/trends, the GFS/Euro have been trending a bit slower and to the west. That’ll be something to keep an eye on, which may put AR/LA more into the action, as opposed to AL and areas farther east. If the system slows a bit and remains more neutrally tilted as opposed to negatively tilted, that’s setting off more alarm bells.

The shortwave is looking somewhat more progressive and compact than some historical major events. 4/27/11 and 4/28/14, for example, were more amplified with upper level lows cutting off. If the progs are correct, a northwesterly 100kt 500mb jet will spell trouble.

Remember your MS vicinity climo. Mean MLCAPE for tornadoes is only ~500 to 1000 J/kg and 1000 to 2000 for significant tornadoes. Global models and longer range NAM get you into the latter camp. Wind profiles speak for themselves, very impressive at face value. 

Global models showing a string-of-pearls QPF signal ahead of the cold front is alarming, especially if there is a pre-frontal trough. I try to not look at forecast soundings too much, but a warm nose/cap around 850-750mb during the first half of the day would suppress precipitation and with cooler temperatures aloft penetrating, that’s why you’re seeing seasonably large instability profiles. 

Summary: Don’t get hung up on details. The synoptic signal is alarming. Watch for a slower/westward trend. 

To be clear, a slower/westward trend would be more or less severe?

Wow 0z Nam is rough. More bullish on the EML and even *more* MLCAPE. Also keeps the large expansion of the risk area. Might be a HOF model run

2 minutes ago, crossbowftw3 said:

4/7/06 and 4/14/12

4/7/06 was also the only 60 sig tornado risk. I wonder if we would see that ever again. 

It could be possible for a day 2 high risk. I doubt it with this event, but it has happened. Twice I think, 2006 and 2012.

Something else to watch is warming at 850 and 700 mb between 18z and 0z. This could put a cap in place over much of the warm sector by 0z. 

1 hour ago, nrgjeff said:

Yes models are definitely struggling. Lots of WF rain would anchor the WF. However it's a robust neutral/negatively tilted system which can push WFs around. Models keep it cool. Yet their QPF swaths hint beasts moving from southwest to northeast. Note they did that a couple times last year, and it turned out non-severe rain with thunder; so, it's not set.

One thing upstairs the turning with height is at or greater than 45 deg. That can sometimes push precipitation off boundary triggers. If it were to close up to say, 30 deg, might have a better shot at a rain-out less severe.

I will say that this is no 4/27. That day turning was nearly 90 degrees; and, a true dry line punched through Dixie. It was like a Plains outbreak. Not happening Easter. 

My bearish lean is for our Region only! Deep South could have a nasty day closer to the Gulf Coast. Still no 4/27, but could be a top 1-2 for just this year 2020 and just the Deep South.

Recent runs of the GFS, ECMWF, and UKMet have been warmer. How much do you think this would change things?

It depends on how prolonged the convection is. Much of Tennesee didn't destabilize on 4/27/11 because of prolonged convection. Had it, then the threat area could of reached further north then it did. 

Still some details to work out but severe weather may be returning to the valley this Weekend

2 inch hail in Jeff City MO

Ehh 1730z Day 2 outlook is late, by like 15 minutes.

What should be expected in terms of structure tomorrow? Like would it be easy to see tornadoes from a distance?

I'm not sure if this has been brought up in the past. If your state is under a stay at home order, is there a good excuse to storm chase if a cop would to ask?