Severe Weather Threat 5/25-5/26, 2024

[MattPetrulli]

00z Suite paints a volatile solution for both of these days.

 

[Fred Gossage]

Those are yesterday's maps. Here is the morning update for today from SPC:

DAY 4-8 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0356 AM CDT WED MAY 22 2024

VALID 251200Z - 301200Z

..DISCUSSION

..DAY 4/SAT - CENTRAL/SOUTHERN PLAINS TO MID-MS VALLEY

AN UPPER SHORTWAVE TROUGH OVER AZ/NM IS FORECAST TO SPREAD EASTWARD
ACROSS THE CENTRAL/SOUTHERN PLAINS TO THE OZARKS VICINITY ON
SATURDAY. AS THIS OCCURS, SOUTHWESTERLY MID/UPPER FLOW WILL
INCREASE. HEIGHT FALLS WILL INDUCE SURFACE CYCLOGENESIS OVER WESTERN
KS AND THE OK/TX PANHANDLES DURING THE DAYTIME. IN RESPONSE, A WARM
FRONT WILL LIFT NORTHWARD ACROSS CENTRAL/EASTERN OK/KS AND MUCH OF
THE MID-MS VALLEY. A SURFACE DRYLINE WILL EXTEND SOUTH FROM THE
SURFACE LOW NEAR THE OK/TX BORDER THROUGH EVENING. DURING THE
NIGHTTIME HOURS, THE SURFACE LOW IS FORECAST TO DEVELOP
EAST/NORTHEAST INTO MO WHILE A COLD FRONT OVERSPREADS PARTS OF THE
CENTRAL/SOUTHERN PLAINS BY SUNDAY MORNING.

A VERY MOIST AND UNSTABLE AIRMASS WILL DEVELOP OVER THE REGION AS
THE WARM FRONT LIFTS NORTH, ALLOWING FOR STRONG DESTABILIZATION. AS
LARGE-SCALE ASCENT AND VERTICAL SHEAR INCREASE DURING THE
AFTERNOON/EVENING, WIDESPREAD THUNDERSTORM DEVELOPMENT IS EXPECTED.
INITIAL SUPERCELLS APPEAR POSSIBLE NEAR THE DRYLINE AND SURFACE LOW
OVER OK/KS. WITH TIME, AN MCS MAY DEVELOP OVER PART OF THE REGION
AND SPREAD EAST INTO AR/MO DURING THE EVENING/OVERNIGHT HOURS. ALL
SEVERE HAZARDS APPEAR POSSIBLE AT THIS TIME, AND HIGHER
PROBABILITIES MAY BE NEEDED IN SUBSEQUENT OUTLOOKS AS MESOSCALE
FEATURES BECOME BETTER RESOLVED FOR HIGHLIGHTING ANY CORRIDORS OF
GREATER SEVERE RISK WITHIN THE BROADER REGION.

..DAY 5/SUN - OZARKS TO THE MID-MS/LOWER OH/TN VALLEYS

A SYNOPTICALLY CONCERNING PATTERN IS EVIDENT ON SUNDAY ACROSS A
BROAD REGION OF THE CENTRAL U.S. THE UPPER TROUGH FROM THE DAY 4/SAT
PERIOD WILL CONTINUE TO SHIFT EAST ACROSS THE MIDWEST ON SUNDAY.
THIS WILL ALLOW STRONG MID/UPPER SOUTHWESTERLY FLOW TO OVERSPREAD
THE REGION AS A DEEPENING SURFACE LOW MOVES FROM MO TOWARD LAKE
MICHIGAN. STRONG TO SEVERE THUNDERSTORMS MAY BE ONGOING ACROSS PARTS
OF MO/THE OZARKS VICINITY. AHEAD OF THIS ACTIVITY, A RAPIDLY
MOISTENING BOUNDARY LAYER WITH UPPER 60S TO LOW 70S F DEWPOINTS IS
EXPECTED TO ENVELOP MUCH OF THE MID-MS/OH/TN VALLEYS. STRONG
DESTABILIZATION AND FAVORABLE VERTICAL SHEAR, ALONG WITH AN
EASTWARD-PROGRESSING COLD FRONT WILL SUPPORT BOTH SUPERCELL STORMS,
AND POSSIBLY A DEVELOPING QLCS, CAPABLE OF ALL HAZARDS. WHILE
DETAILS REGARDING MORNING CONVECTION AND STORM MODE REMAIN SOMEWHAT
UNCERTAIN, HIGHER-END SEVERE POTENTIAL APPEARS POSSIBLE WITH THIS
PATTERN ACROSS PORTIONS OF THE REGION FROM MIDDAY INTO THE NIGHTTIME
HOURS.

..DAYS 6-8/MON-WED

SPREAD AMONG MODEL GUIDANCE INCREASES QUITE A BIT BY MONDAY. SOME
SEVERE POTENTIAL IS POSSIBLE ANYWHERE FROM THE SOUTHERN STATES TO
THE MID-ATLANTIC AS THE UPPER TROUGH LIFTS EAST/NORTHEAST. HOWEVER,
DETAILS REGARDING STORM EVOLUTION ON DAY 5/SUN INTO EARLY MONDAY,
ALONG WITH DIFFERING EVOLUTION OF THE SURFACE PATTERN BY VARIOUS
GUIDANCE RESULTS IN LOW PREDICTABILITY.

BY TUESDAY AND WEDNESDAY, AN UPPER RIDGE IS EXPECTED TO MOVE FROM
THE WESTERN U.S. INTO THE PLAINS. THIS SHOULD MOSTLY SHUT DOWN
SEVERE POTENTIAL WEST OF THE MS RIVER.

..LEITMAN.. 05/22/2024

Based of current guidance, I'd be surprised if there isn't eventually an Enhanced Risk with time that comes as far southeast as north Mississippi and north Alabama for the Sunday part of this.

 

[Clancy]

SPC's wording is rather robust regarding D5. Definitely not mincing words.

...Day 5/Sun - Ozarks to the Mid-MS/Lower OH/TN Valleys...

A synoptically concerning pattern is evident on Sunday across a
broad region of the central U.S. The upper trough from the Day 4/Sat
period will continue to shift east across the Midwest on Sunday.
This will allow strong mid/upper southwesterly flow to overspread
the region as a deepening surface low moves from MO toward Lake
Michigan. Strong to severe thunderstorms may be ongoing across parts
of MO/the Ozarks vicinity. Ahead of this activity, a rapidly
moistening boundary layer with upper 60s to low 70s F dewpoints is
expected to envelop much of the Mid-MS/OH/TN Valleys. Strong
destabilization and favorable vertical shear, along with an
eastward-progressing cold front will support both supercell storms,
and possibly a developing QLCS, capable of all hazards. While
details regarding morning convection and storm mode remain somewhat
uncertain, higher-end severe potential appears possible with this
pattern across portions of the region from midday into the nighttime
hours.

 

[Clancy]

CSU's ML outlooks painting some pretty extraordinary probabilities.

 

[CheeselandSkies]

Whiffed yesterday in IA, looks like I get another crack at it Sunday. Never really chased much south of Peoria in Illinois, or east into Indiana, but I have Monday off for Memorial Day so why not?

 

[Wind Driven Coconut]

Liz Leitman has been writing the extended forecasts for the last week. She didn’t pull the trigger on 30% for Iowa yesterday until day 4 probs so must be a pretty concerning look to pull it for day 5 this morning. I’ve always considered her to be a bit measured in forecasts. Another serious week ahead it appears.

 

[CheeselandSkies]

Liz Leitman has been writing the extended forecasts for the last week. She didn’t pull the trigger on 30% for Iowa yesterday until day 4 probs so must be a pretty concerning look to pull it for day 5 this morning. I’ve always considered her to be a bit measured in forecasts. Another serious week ahead it appears.

Just as long as she gets the day of the week right this time...

 

[Wind Driven Coconut]

Just as long as she gets the day of the week right this time...

A little off topic but I do think it’s wild that the SPC folks flip back and forth from day shifts to overnight shifts every few weeks. I can’t imagine what that 7th consecutive overnight shift is like when your body rhythms are set to regular hours.

 

[jiharris0220]

I’d like to remind people that even after may, prolific severe weather outbreaks can easily occur in June/July.

Literally last year and 2014 had their worst tornado outbreaks occur in those months. 2024 potentially could still have a lot more to offer in the summer.

 

[treypops]

I’d like to remind people that even after may, prolific severe weather outbreaks can easily occur in June/July.

Literally last year and 2014 had their worst tornado outbreaks occur in those months. 2024 potentially could still have a lot more to offer in the summer.

Yes they can easily occur and have occurred.

But they are not as frequent or common. There has to be some pretty unique dynamics in place for it to happen.

 

[kcyalater]

there’s a saucy little supercell with a TOR SSE of Tulsa just doing it’s thing at 8:24am.

 

[kcyalater]

just realized i posted in the wrong thread ^^^ apologies!

 

[JPWX]

Yes they can easily occur and have occurred.

But they are not as frequent or common. There has to be some pretty unique dynamics in place for it to happen.

Right and all you have to do is look at Summer 2023 across the Deep South with the big hail

 

[tennessee storm chaser]

Yes they can easily occur and have occurred.

But they are not as frequent or common. There has to be some pretty unique dynamics in place for it to happen.

June into July start see best dynamics move north , northern plains to upper Midwest …. As the main jet starts migrate north during summer

Right and all you have to do is look at Summer 2023 across the Deep South with the big hail

i was pointing more tornadoes

 

[treypops]

June into July start see best dynamics move north , northern plains to upper Midwest …. As the main jet starts migrate north during summer

i was pointing more tornadoes

Yes, and location has a lot to do with this and I should have clarified. In the Mid-South/Deep South, it's rarer. In the upper midwest and rust belt, it's a little more common.

 

[Clancy]

Yes, and location has a lot to do with this and I should have clarified. In the Mid-South/Deep South, it's rarer. In the upper midwest and rust belt, it's a little more common.

If I remember correctly, protracted periods of broad zonal flow had a lot to do with some of last year's Southern summer events and didn't look quite like the normal summer synoptics this region of the US is used to. Come summer a lot of the notable events happen through the Midwest and Upper Plains.

 

[jiharris0220]

The mods are going to have a field day with organizing this.

 

[tennessee storm chaser]

sunday afternoon , the atmosphere from about memphis tn to southern illinois is about as violtile of a atmosphere you can get with the dynamics latest models r showing... beter hope mid level cap can hold firm. waiting for euro now

 

[JBishopwx]

The mods are going to have a field day with organizing this.
View attachment 27491

Sorry for any confusion on the thread i started, but its one of those you can't make everyone happy.

 

[Brice W]

Sorry for any confusion on the thread i started, but its one of those you can't make everyone happy.

I think we both made a thread around the same time and it kinda through everything off, my apologies to you sir!