Severe Weather Threat 4/27-4/28, 2024 - (Saturday, Sunday)

[wx_guy]

Has the nadocast ever gone 60%, let alone such a big area?

That is the 2020 models, though, not sure why they were used. Here's the 12z run of the 2022 models.

 

[jiharris0220]

Mesoscale update

 

[cincywx]

MESOSCALE DISCUSSION 0539
NWS STORM PREDICTION CENTER NORMAN OK
1057 AM CDT SAT APR 27 2024

AREAS AFFECTED...NORTHWEST TX...WESTERN/NORTHERN OK...AND SOUTHEAST
KS

CONCERNING...TORNADO WATCH 144...

VALID 271557Z - 271730Z

THE SEVERE WEATHER THREAT FOR TORNADO WATCH 144 CONTINUES.

SUMMARY...SEVERE THREAT WILL FURTHER INCREASE INTO THE AFTERNOON
FROM PARTS OF NORTHWEST TEXAS INTO SOUTHEAST KANSAS, INCLUDING
POTENTIAL FOR A COUPLE STRONG TORNADIC SUPERCELLS. A BROADER TORNADO
AND/OR MULTIPLE PDS/NON-PDS TORNADO WATCHES WILL BE NEEDED PRIOR TO
THE 18Z EXPIRATION OF WW 144.

DISCUSSION...SURFACE ANALYSIS PLACED THE NEARLY STATIONARY DRYLINE
ACROSS THE EASTERN TX PANHANDLE THROUGH NORTHWEST TX. THE DEEPEST
CONVECTION IS AHEAD OF THE DRYLINE IN WEST-CENTRAL TO NORTH-CENTRAL
OK, WHICH INCLUDES A SUPERCELL IN CLUSTER AND A DOWNSTREAM DISCRETE
SUPERCELL. SURFACE WARMING HAS BEEN MORE PRONOUNCED IN PARTS OF
CENTRAL OK, GENERALLY ALONG AND EAST OF THE I-35 CORRIDOR. THE
LEADING DISCRETE SUPERCELL SHOULD HAVE RELATIVELY UNINTERRUPTED
INFLOW AS IT IMPINGES ON THIS RELATIVELY MAX IN BOUNDARY-LAYER
WARMING. AMID A 45-KT SOUTHERLY LOW-LEVEL JET PER THE TLX VWP DATA,
POTENTIAL WILL EXIST FOR CYCLIC TORNADOES THAT MAY BE STRONG. STRONG
MID-LEVEL ROTATION HAS ALSO BEEN NOTED WITH THE SUPERCELL IN CLUSTER
NOW CENTERED IN DEWEY COUNTY, OK, AND THIS STORM SHOULD POSE A
CONTINUED THREAT FOR ALL HAZARDS.

ADDITIONAL STORMS SHOULD REGENERATE ALONG THE DRYLINE FARTHER SOUTH
INTO NORTHWEST TX THROUGH THE AFTERNOON GIVEN MINIMAL MLCIN. WITH
WEAKER FORCING FOR ASCENT RELATIVE TO FARTHER NORTH, THERE IS SOME
UNCERTAINTY IN HOW QUICKLY THIS ACTIVITY WILL BECOME SEVERE. BUT THE
OVERALL ENVIRONMENT WILL FAVOR DISCRETE SUPERCELL DEVELOPMENT,
ESPECIALLY AS THE BOUNDARY LAYER FURTHER WARMS.

..GRAMS.. 04/27/2024

considering PDS watches for parts of the moderate risk area

 

[Maxis_s]

considering PDS watches for parts of the moderate risk area

Don't wanna sound like a weenie but I think this is gonna be upgraded to a high risk. Cloud cover is gone and the mode is becoming more discrete on models. I don't think there's much of a failure mode left.

 

[Tempestas Tonitrua]

Don't wanna sound like a weenie but I think this is gonna be upgraded to a high risk. Cloud cover is gone and the mode is becoming more discrete on models. I don't think there's much of a failure mode left.

Trey said he could see a small high risk placed over Oklahoma but it all depends on how long the cells can remain discrete

 

[Muwx]

12z cams didn’t inspire a ton of confidence about how this is going to unfold. A high risk would surprise me.

 

[cincywx]

i think they are gonna wait until closer to the 20z outlook to start thinking about that

 

[jiharris0220]

Cap is remaining quite stout for now.

 

[joshoctober16]

Don't wanna sound like a weenie but I think this is gonna be upgraded to a high risk. Cloud cover is gone and the mode is becoming more discrete on models. I don't think there's much of a failure mode left.

only type of bust is the qlsc/ mess bust, ignoring that reason i would say ya... high risk

 

[Avon]

Wouldn't be surprised if this goes high risk. Looking like a classic and very scary set up for monster tornadoes in the risk area.

 

[Clancy]

Not that today will be anything like either of these days, but the current evolution of this morning convection reminds me a bit of the morning-to-midday stuff that went over N AL and southern TN on 4/27/11, as well as 3/2/12. Probably making for a boundary-rider situation, where any cells that move along it could become locally enhanced.

 

[Tempestas Tonitrua]

Not that today will be anything like either of these days, but the current evolution of this morning convection reminds me a bit of the morning-to-midday stuff that went over N AL and southern TN on 4/27/11, as well as 3/2/12. Probably making for a boundary-rider situation, where any cells that move along it could become locally enhanced.

Yep. Those storms are moving north east out of the main risk area later and any storms that fire later on will be able to ride that and take advantage of the rich environment to their east.

 

[wx_guy]

Sticking with MDT looks like. I think that's the best call currently.

 

[cincywx]

DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1125 AM CDT SAT APR 27 2024

VALID 271630Z - 281200Z

...THERE IS A MODERATE RISK OF SEVERE THUNDERSTORMS THIS AFTERNOON
AND EVENING ACROSS PORTIONS OF SOUTHERN KANSAS...MUCH OF
OKLAHOMA...AND NORTHWEST TEXAS....

..SUMMARY

SEVERE THUNDERSTORMS ARE LIKELY TODAY AND TONIGHT ACROSS THE
SOUTHERN AND CENTRAL PLAINS INTO THE LOWER TO MID MISSOURI VALLEY.
THE MOST NUMEROUS/INTENSE STORMS ARE EXPECTED FROM NORTH TEXAS INTO
OKLAHOMA AND SOUTHEAST KANSAS, WHERE STRONG TORNADOES, VERY LARGE
HAIL OF 2-3 INCHES IN DIAMETER AND DAMAGING WINDS OF 60-80 MPH ARE
ALL POSSIBLE.

...A REGIONAL OUTBREAK OF SEVERE THUNDERSTORMS IS FORECAST FOR THIS
AFTERNOON AND EVENING ACROSS PARTS OF KS/OK. VERY LARGE HAIL AND
STRONG TORNADOES ARE POSSIBLE..

..OK/NORTHWEST TX/SOUTH-CENTRAL KS

WATER VAPOR IMAGERY SHOWS THE MAIN UPPER TROUGH IS STILL BACK OVER
SOUTHERN AZ, WITH A RAPIDLY EJECTING MID/UPPER LEVEL JET STREAK
NOSING INTO OK/TX. THIS LEAD FEATURE HAS AIDED IN THE DEVELOPMENT
OF SEVERE STORMS THIS MORNING OVER PARTS OF WEST TX/OK. STORMS WILL
DEVELOP NORTHEASTWARD THROUGH THE AFTERNOON INTO CENTRAL KS, DESPITE
AN EXPANSIVE ANVIL SHIELD FROM THE MORNING CONVECTION. THESE STORMS
WILL POSE A RISK OF VERY LARGE HAIL AND A FEW TORNADOES THROUGH THE
AFTERNOON AND EARLY EVENING.

FARTHER SOUTH, THE AIR MASS ACROSS MUCH OF CENTRAL/WESTERN OK AND
NORTHWEST TX CONTINUES TO WARM/DESTABILIZE AS TEMPERATURES RISE
THROUGH THE MID/UPPER 70S - ELIMINATING CINH. ONLY WEAK UPPER
FORCING THROUGH THE AFTERNOON WILL RESULT IN CHAOTIC DEVELOPMENT OF
DISCRETE SUPERCELLS IN A VERY STRONGLY SHEARED AND VERY UNSTABLE
ENVIRONMENT. FORECAST SOUNDINGS SHOW VERY STEEP MID-LEVEL LAPSE
RATES, AMPLE LOW-LEVEL MOISTURE, AND STRONG/INCREASING SHEAR
PROFILES THROUGH THE DAY. DETAILS OF TIMING AND LOCATION ARE
NEBULOUS, BUT THOSE STORMS THAT DEVELOP WILL POSE A RISK OF VERY
LARGE HAIL AND STRONG AND POSSIBLY LONG-TRACK TORNADOES. THE
STRONGER LARGE-SCALE FORCING WILL ARRIVE AROUND/AFTER DARK, WITH A
GREATER EASTWARD SURGE OF STORMS ACROSS CENTRAL OK EXPECTED. THIS
ACTIVITY MAY ORGANIZE UPSCALE IN BOWING SEGMENTS WILL AN INCREASING
RISK OF DAMAGING WINDS ALONG WITH HAIL AND TORNADOES INTO SOUTHEAST
KS AND NORTHEAST OK TONIGHT.

..SOUTHEAST CO INTO NORTHERN KS

A RATHER STRONG SURFACE BOUNDARY EXTENDS FROM SOUTHEAST CO ACROSS
MUCH OF NORTHERN KS. RELATIVELY STRONG HEATING ALONG THIS BOUNDARY
AND MODERATE INSTABILITY WILL LEAD TO SCATTERED THUNDERSTORM
DEVELOPMENT BY MID-AFTERNOON ALONG THE ENTIRE CORRIDOR. STEEP
MID-LEVEL LAPSE RATES, STRONG DEEP-LAYER SHEAR, AND FAVORABLE
LOW-LEVEL WIND PROFILES IN VICINITY OF THE BOUNDARY WILL POSE A RISK
OF VERY LARGE HAIL AND A FEW TORNADOES THROUGH THE AFTERNOON AND
EARLY EVENING. THIS ACTIVITY IS EXPECTED TO BUILD EASTWARD THIS
EVENING ALONG THE SAME BOUNDARY INTO PARTS OF SOUTHERN IA/NORTHERN
MO, WITH A CONTINUED RISK OF LARGE HAIL ALONG WITH AN INCREASING
THREAT OF DAMAGING WINDS.

..HART/JEWELL.. 04/27/2024

 

[wx_guy]

Point forecast for STORM-NET looking at Ames, Oklahoma, northwest of OKC. For reference, it performed fantastically yesterday. EDIT: If anyone has any locations you want to see, let me know.

 

[jiharris0220]

Much stronger wording though with this update.

 

[TornadoFan]

Much stronger wording though with this update.
View attachment 25823

When they say chaotic development, do they storms so clustered together or just alot of discrete storms in general?

 

[jiharris0220]

Just a a lot of discrete cells that could fire randomly.

 

[wx_guy]

Very energy-rich environment! Surface based CAPE already 3k-4k across most of Oklahoma and eastern Kansas. The 6-hour forecast on the RAP mesoanalysis has a huge area exceeding 4k CAPE and even 4500-5k CAPE.

 

[rushdude]

Fingers crossed that cap remains in place over here in northern TX