SamuelG

Absolutely perfect MD!

At this point, where would we draw a line between a shelf cloud and a wall cloud? A lot of it is semantics really, but interesting topic nonetheless

Not at all actually, my obsession kicked off before I could even remember(which seems unusual these days?)

I’m glad I’m not the only one on this train

The only proper target today

Cold front probably lifted out that warm nose and shear increased rougly to 300m2/s2 0-1SRH!

Composite Reflectivity from the 12z NSSL MPAS HN model, from pivotal weather.

Composite Reflectivity from the 12z NSSL MPAS HT model, from pivotal weather.

Now if the MPAS models verify...

Further north and west, closer to the low, weaker mid level winds will be present, yielding for lower SRI and smaller updrafts. Further south and east in the zone with higher winds, stronger SRI and somewhat larger updrafts may develop, leading to potentially stronger tornadoes.

The level of destabilization will depend on the extent of daytime heating in this area. Assuming HRRR is correct, very strong low level instability would develop and bring a pretty decent chance of tornadoes. It is one of the more impressive cold core setups I have seen.

500mb windspeeds with geopotential height and wind barbs. Image from aguacerowx.com

18z HRRR upper air sounding taken from north central Illinois on March 19, 2025 at 21 UTC.

Pretty solid cold-core setup in northern and eastern Illinois tomorrow. Impressive moisture return will allow for low to mid 50s F dewpoints in northern/eastern Illinois. On top of this moisture plume, ~-20C temperatures will allow for strong low and mid level lapse rates to develop.

Is there a particular reason why HRRR(rather the entire ARW core in general) tends to overmix?

An ensemble breaking a pressure record 6 days out is a feat by itself

Same energy as NE NE.

When was the last time all ensembles across the board had such a deep low this far out?

No matter what, the consequences are very worrying.

Seeing the cold front interacting with the smoke plume is very interesting!

I believed that without the EML/warm nose on 2/26 being as strong as it was, the tornado threat would have been much weaker. This event is much different since the EML is much weaker and it’s firing after dark and along a NE/SW oriented cold front, so it’s a very difficult forecast.

Destabilization may be a concern as the convection fires only 2-3 hours after the prior convection moves through, but given a potent dry slot it should allow for at least some destabilization.

2m AGL Dewpoint plot from PivotalWeather, valid 20z on Sunday the 2nd. From the RAP model.

Upper Air Sounding valid 20z on Sunday, in far southwest Oklahoma.

A coldcore-ish setup will be in place in the TX panhandle/SW OK tomorrow. Despite the lack of quality moisture, morning convection will allow for higher moisture amounts in the area. A very convergent/vorticious zone will allow for some tornado potential for supercells that form.

I wonder how the ones who release the weather balloons every morning and evening are doing, I’m worried on what is to come

Need more of this kind of energy!

May lead to an epic sunset here(hopefully)

I feel Waldo is not talked about aa much as it should be. Photogenic rope/wedge, hitting nothing, and with a pretty unique environment

HRRR F00 upper-air sounding valid May 6, 2024 at 22z, taken in Watonga, Oklahoma.

Surface analysis map centered on Wichita, KS valid 2207z on May 6, 2024.

-very unstable airmass along/near the dryline, yet storms were still having outflow dominance issues. Perhaps it was the somewhat weak low-level shear and/or the almost SSWerly surface winds?

This only makes me wonder even more why something like May 6 underperformed; my impression this entire time to why May 6 didn't do much was that you needed that very moist airmass right along the dryline, as many large synoptic plains outbreaks have. This one instead had that somewhat dry but-

Water Vapor Satellite Imagery valid 16:51UTC.

Water Vapor imagery depicts much higher water vapor in NW OK and the TX panhandle. This mass is moving east and will be impacting us OKC/Norman folks soon, probably in the form of a mix/snow.

Although the majority consensus is steadily trending toward the NAM, they still have a less significant severe event due to displacement of mid level flow and diffluence from the warm sector. HRRR wind profiles show a lack of mid level shear across the warm sector, and more veered profiles.

Currently, the NAM model has a much more potent shortwave across Arkansas. There’s much more diffluence across the northern edge of the warm sector compared to other models(HRRR, GFS, EURO), in which case would raise the severe and tornado threat.

Tomorrow has a pretty intriguing severe setup; a very strong low level atop an unstable (~1k J/kg CAPE) airmass. It is currently unclear on the extent of the warm sector and the geometry of the system, but a change in these factors could greatly impact the severe risk.

A plot displaying differences between observed temperatures and the 12z HRRR model temperatures.

Andy Wade's temperature verification website is wonderful for this!