Severe Threat May 15-16, 2025

[warneagle]

18z NAM has a monstrous long tracked supercell on Friday initiating in MO and tracking through the afternoon into KY along the Ohio River.

I've seen this movie before. I remember how this ends.

 

[Ozonelayer]

I've seen this movie before. I remember how this ends.

I think most of us have, the ending was awaited but it honestly seemed like it never came. To be fair, I doubt we will have another Mayfield-like tornado for a while.

 

[ColdFront]

I think most of us have, the ending was awaited but it honestly seemed like it never came. To be fair, I doubt we will have another Mayfield-like tornado for a while.

Agreed. this isn’t hyperbole but there’s a much higher chance of a super outbreak occurring again before we get a confirmed 160+ mile tornado

 

[Cyclonic Paracosm]

Agreed. this isn’t hyperbole but there’s a much higher chance of a super outbreak occurring again before we get a confirmed 160+ mile tornado

Especially of the intensity of said 160+ mile nado.

 

[JPWX]

12z Euro is still very aggressive Friday evening across North MS as far as Dewpoint and CAPE values. Bulk shear is lower, but increases thereafter.

All times valid at 7pm Friday.

Would not surprise me in the least if we see that current Slight Risk at Day 4 expand further south and east/west with potential for a Enhanced Risk within the Slight Risk area. Tornado threat overall dependent upon storm mode, but a tornado threat WILL BE there.

 

[AJS]

Agreed. this isn’t hyperbole but there’s a much higher chance of a super outbreak occurring again before we get a confirmed 160+ mile tornado

I still can’t believe the Mayfield Tornado even happened. It felt like an EAS scenario type event. Truly unreal to still think about to this day.

 

[James Sm.]

For what it's worth, the RRFS has a somewhat similar idea to the nam3k for thurs evening: View attachment 41377

Same story for the MPAS-RT and the new MPAS-G:

 

[CheeselandSkies]

Notable slowdown of the system across 18Z hi-res guidance. One of my main concerns with previous runs of models such as the GFS was their wanting to sweep the cold front practically all the way to Lake Michigan by 21Z (4 PM) Thursday (if nothing else, for the simple fact of giving me enough time to get on a storm after getting off work at 1 PM). SPC noted in their Day 4 outlook yesterday that it was possibly exhibiting its fast bias, and so far things would indeed seem to be trending in that direction.

 

[Clancy]

12z Euro is still very aggressive Friday evening across North MS as far as Dewpoint and CAPE values. Bulk shear is lower, but increases thereafter.

All times valid at 7pm Friday.

Would not surprise me in the least if we see that current Slight Risk at Day 4 expand further south and east/west with potential for a Enhanced Risk within the Slight Risk area. Tornado threat overall dependent upon storm mode, but a tornado threat WILL BE there.

It's a weird setup down in these parts. I'm used to February/March/April systems and all their complications, but this one poses different forecasting challenges. There's a chance no one in MS/AL/GA will see even a drop from anything other than a shower during the day Friday, but if even one storm were to take root, it could become quite dangerous. Even with somewhat unidirectional shear, the strong instability could account for it.

 

[CheeselandSkies]

Many forecasters noting concerns with dry EML and mixing for Thursday; however, the difference in CAM initiation at this range between that and April 28 is quite stark. 3K NAM, MPAS and RRFS all develop discrete convection with pronounced UH swaths.

Very bizarre seeing that be the main failure mode; around here 99 times out of 100 it'll be excessive early convection working over the atmosphere and preventing destabilization.

 

[Sky_I565]

It's trying. Its spinning

 

[Atlantic]

Either this is going to be a bu$T in the end, or we will be throttling here in a few days.

May’s gone up the ladder halfway and has to decide whether to go up further (a big storm system like this one coming up possibly) or go down the ladder again (trend down the threat hopefully)

 

[Kds86z]

Either this is going to be a bu$T in the end, or we will be throttling here in a few days.

May’s gone up the ladder halfway and has to decide whether to go up further (a big storm system like this one coming up possibly) or go down the ladder again (trend down the threat hopefully)

My prediction is 50/50 it could go either way.,

 

[Grand Poo Bah]

Man, the RAP is really not painting a pretty picture



It's just absolutely pounding Arkansas with cells. I'd bet that'll congeal into a QLCS fairly quickly though. I'd imagine it's the cells up in Missouri that''ll cause the bigger issues.



Here's some soundings from Arkansas and Missouri. The RAP doesn't seem to think the cap is really hindering anything.

 

[Kds86z]

Where’s @wx_guy been? We may need him this week lol..

 

[Grand Poo Bah]

Wisconsin convection finally showing on 00Z HRRR, and it's also showing the lowest pressure system yet at 976mb.




Every single cell is spinning....

 

[Grand Poo Bah]

A fun feature of tropical tidbits is it lets you grab soundings from models that Nexlab doesn't. And it has a map!

Wisconsin is interesting because these soundings don't look super tornadic, but a lot of the hodographs are showing an almost perfectly uniform 540-720 degrees of rotation with height. So it'll be really interesting to see how that plays out if true. If tornadoes do form, they'll be skyscrapers and extremely photogenic! Hope you can get us some pictures @CheeselandSkies and @James Sm.! If you aren't being bombarded with 5 inch hail that is! lol



Can't quite see far enough to know what the model is projecting for Kentucky yet, but if the very last frame of the 00z HRRR is anything to go by, it won't be pretty.

 

[CheeselandSkies]

Box-averaged RAP sounding (almost forgot I could do those now I've finally forked over for Pivotal Plus) for southern WI at 21Z Thursday:



Very interesting that one analog date is quite notorious and the other is...in late July.

Here's one valid for an hour later:

 

[Grand Poo Bah]

Box-averaged RAP sounding (almost forgot I could do those now I've finally forked over for Pivotal Plus) for southern WI at 21Z Thursday:

Very interesting that one analog date is quite notorious and the other is...in late July.

Here's one valid for an hour later:

I'm really starting to think the cap is going to help tornado outbreak potential rather than hurt it. That analog has popped up one too many times for me to think it will be an issue.

Where's @jiharris0220 at?! This set up is right up their alley!

 

[joshoctober16]

meanwhile other spots have it too wet

i know it says PDS but the psbl haz is of course not perfect.
there is one large obvious issue and its the whole MLCINH not being at -1 to -49 its at 0 , obviously causing a huge mess of too much convections.

the LowRH is a bit high as well.