Severe WX March 30th- April 1st 2023 (South, Southeast, Ohio Valley, Upper Midwest)

[CheeselandSkies]

Yeah, 3/28/20 a lot of potential was wasted on the northern end by junk convection going most of the day. I didn't think things would even really fire in this area, so I didn't chase. Things did get going in northern IL and produce a few tornadoes as you can see on the SPC image, but it was toward dusk and it was also during the highly discombobulating early days of the COVID-19 lockdown.

 

[JPWX]

I've been working closely with our EMA director for Monroe County MS and the mayor of Amory sending them weather updates concerning Friday and will continue to next week. Here's my latest one: "Friday Storm Timing Update: General Thunderstorm Timing: 4pm Friday through 3am Saturday morning with Severe Storm Timing: 6pm Friday through 1am Saturday morning. This will be addressed in tomorrow's weather text. I have no changes on the overall threats, but I am more concerned about the damaging wind/tornado threat than the threat for large hail. Rainfall amounts will be in the half inch to 1 inch range with locally higher amounts possible."

 

[CheeselandSkies]

Now this one @Casuarina Head I will give you is going to have a fairly narrow instability axis...but it might not matter as it's going to be moving with the storms. This threw me off last year with the Winterset setup as I didn't consider that could be the case. Assumed the storms would just move out of it and die off as usually happens.

 

[MattPetrulli]

Nice

 

[CheeselandSkies]

Even more pretty colors up on the northern end (Midwest view). This model also implies a much higher threat for southern WI and northern IL than the NAMs so far.

 

[notsoencrypted]

Even more pretty colors up on the northern end (Midwest view). This model also implies a much higher threat for southern WI and northern IL than the NAMs so far.

I was just noticing this myself.

 

[CheeselandSkies]

I was just noticing this myself.

View attachment 19322

Yeah, that is...eyebrow raising, in the face of everything else with this setup.

There's better model agreement than I've seen in a long time. GFS, NAM, 3KM NAM, RAP and now HRRR all have a significant setup in pretty much the same place, but they still do differ in important details that will determine the ceiling of this event and where the most dangerous storm(s) occur.

 

[notsoencrypted]

Yeah, that is...eyebrow raising, in the face of everything else with this setup.

There's better model agreement than I've seen in a long time. GFS, NAM, 3KM NAM, RAP and now HRRR all have a significant setup in pretty much the same place, but they still do differ in important details that will determine the ceiling of this event and where the most dangerous storm(s) occur.

I think it was a MKX forecast discussion from this afternoon that indicated the cooling effect of Lake Michigan at this time of year is not often well represented by the models, which meant they had more doubts for more northern threats. I'll go see if I can find what they actually said...

Edit: Yeah, it was MKX, though I look forward to seeing what they will have to say in their next discussion.

However, this is spring time in the Midwest and the setup for severe is conditional. Still has some concern with a few factors that may limit southern WI potential. The first and biggest concern is a tale as old as time; the battle between Lake Michigan cold air and the warm front. Historically during the early spring season the lake has a great deal of impact on the warm front up in our area and how far north it progresses. Global models tend to not handle this all that well and can see hints of the warm front progression being limited in the 12z CMC model. So there is still some uncertainty from that aspect which would limit severe more to elevated convection than surface based. On top the warm front position, there is some models hinting at limited instability as well. The 06z GEFS and EPS only have medium to high probabilities of CAPE exceeding 500 J/kg in the southwestern part of our CWA.

 

[Clancy]

00Z HRRR depicts two distinct areas of supercell development, one in the Arklatex, Southern Missouri and Illinois, and another in parts of Iowa, Wisconsin and northern Illinois.

 

[jiharris0220]

The soundings this hrrr run has got to be the most robust in quite a long time. vast areas of helicity values of 500/1000+, overlapping with cape values in the 1000-3000+ range.
Vertical wind profiles are pretty much veered throughout the entirety of the cold front with temps in the mid 60s/70s and dews in the 60s and up.
A semi discreet mode is apparent all along the cold front too, and to my surprise it actually seems like the hrrr has a completely discreet mode near the cold core section of the cyclone.
Jesus.

 

[CentralKyWeather]

Oz Hrrr guidance is pretty telling of a significant outbreak. Southeast Illinois, Southwest Indiana, and Northwest KY looks like the Hotspot. Latest guidance is showing pretty considerable daytime heating in this area.
Usually with this type of setup in this general area with ample instability/shear it usually equates to an outbreak imo.

 

[TornadoFan]

Excuse me?

 

[JPWX]

My latest concerning Friday focusing solely on North MS:

A significant severe weather/tornado outbreak is expected across North MS into parts of Central MS Friday into early Saturday morning with additional severe storms expected next week. More on that later after we get through Friday. Let's break it down.

Storm Timing: 4pm Friday through 3am Saturday morning.

Severe Storm Timing: 6pm Friday through 1am Saturday morning.

Cities/Towns In The Greatest Severe Risk Zone: Tupelo, Smithville, Amory, Fulton, and Nettleton.

Primary Threats: tornadoes (some strong), damaging winds of 70 to 80mph, and golf ball size hail.

Additional Hazards: Non-thunderstorm winds to 20mph gusts to 35mph.

 

[ColdFront]

Even more pretty colors up on the northern end (Midwest view). This model also implies a much higher threat for southern WI and northern IL than the NAMs so far.

That’s the first thing that caught my eye on the 0Z HRRR. Upper Midwest getting in on the action

 

[ColdFront]

Just saw a 4/17/98 00z BMX analog off a sounding in North Eastern Illinois on Friday.

 

[andyhb]

It’s not just the HRRR that went nuts at 00z. Every CAM has a solution with multiple supercells from IL/WI/IA to Arkansas tracking through a highly sheared warm sector. One of the more dangerous sets of HREF members that I’ve ever seen frankly.

 

[JPWX]

@andyhb just curious what your thoughts are concerning North MS area particularly Northeast MS for Friday?

 

[ColdFront]

I know FV3 is considered the supercell printer… but goodness gracious

 

[JPWX]

I know FV3 is considered the supercell printer… but goodness gracious
View attachment 19325

 

[TornadoFan]

I know FV3 is considered the supercell printer… but goodness gracious
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