752  
ACUS01 KWNS 250554  
SWODY1  
SPC AC 250552  
 
DAY 1 CONVECTIVE OUTLOOK  
NWS STORM PREDICTION CENTER NORMAN OK  
1152 PM CST WED FEB 24 2021  
 
VALID 251200Z - 261200Z  
 
...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS FOR PORTIONS OF  
NORTHERN TEXAS INTO SOUTHERN ARKANSAS...NORTHERN LOUISIANA AND  
CENTRAL MISSISSIPPI...  
   
..SUMMARY
 
 
A COUPLE SEVERE THUNDERSTORMS MAY IMPACT A CORRIDOR ACROSS  
NORTH-CENTRAL TEXAS THROUGH THE ARK-LA-TEX VICINITY TONIGHT, WITH A  
COUPLE INSTANCES OF MARGINALLY SEVERE HAIL OR DAMAGING GUSTS  
POSSIBLE.  
   
..SYNOPSIS
 
 
BROAD CYCLONIC FLOW ALOFT WILL DOMINATE THE UPPER PATTERN ACROSS THE  
CONUS THROUGH TODAY. AN EMBEDDED MID-LEVEL TROUGH WILL TRAVERSE THE  
SOUTHERN PLAINS WHILE A SECOND TROUGH ALOFT IMPINGES ON THE PACIFIC  
NORTHWEST. ACROSS THE SOUTHERN PLAINS INTO PORTIONS OF THE  
MID-SOUTH, A STABLE BOUNDARY LAYER WILL BE IN PLACE FOR MOST OF THE  
PERIOD. NONETHELESS, A 35+ KNOT 850 MB JET IS EXPECTED TO DEVELOP BY  
LATE AFTERNOON/EARLY EVENING IN RESPONSE TO THE APPROACHING UPPER  
TROUGH, TRANSPORTING APPRECIABLE MOISTURE NORTHWARD (EVIDENT VIA 00Z  
LCH/LIX OBSERVED SOUNDINGS), BENEATH 6-7 C/KM MID-LEVEL LAPSE RATES,  
RESULTING IN UP TO 500 J/KG MUCAPE ACROSS PORTIONS OF NORTHERN TX  
INTO CENTRAL MS IN THE 21-12Z TIME FRAME. DEEP-LAYER ASCENT WILL BE  
IN PLACE TO INITIATE ELEVATED CONVECTION, WITH AN 80 KT 500 MB JET  
STREAK OVERSPREADING THE REGION BENEATH THE RIGHT-ENTRANCE REGION OF  
A 300 MB JET STREAK. DESPITE MARGINAL INSTABILITY, STRONG DEEP-LAYER  
DIRECTIONAL AND SPEED SHEAR MAY ENCOURAGE STORM ORGANIZATION AND  
LONGEVITY, WITH A COUPLE OF STRONG TO BRIEFLY SEVERE STORMS  
POSSIBLE.  
 
ACROSS THE NORTHWEST U.S., MEAGER BUOYANCY PRECEDING THE APPROACH OF  
A MID-LEVEL TROUGH AND ASSOCIATED SOURCE OF ASCENT MAY ENCOURAGE  
ISOLATED THUNDERSTORM DEVELOPMENT TO THE LEE OF THE CASCADES.  
ELSEWHERE ACROSS THE CONUS, COOL AND STABLE CONDITIONS WILL SERVE TO  
MITIGATE THUNDERSTORM CHANCES.  
 
...SOUTHERN GREAT PLAINS INTO THE LOWER MISSISSIPPI VALLEY  
TONIGHT...  
WITHIN THE 21-00Z PERIOD, CONVECTIVE INITIATION IS EXPECTED TO OCCUR  
WITHIN A WARM-AIR ADVECTION REGIME AT THE NOSE OF A DEVELOPING  
LOW-LEVEL JET. FORECAST SOUNDINGS SUGGEST THAT THE SOUTHERN PLAINS  
STORMS WILL REMAIN ROOTED ABOVE 850 MB GIVEN THE AFOREMENTIONED  
STABLE LAYER. MAINLY SMALL HAIL IS EXPECTED TO BE THE MAIN THREAT  
WITH THESE STORMS GIVEN SKINNY CAPE PROFILES AS DEPICTED BY FORECAST  
SOUNDINGS, HOWEVER A COUPLE STONES OVER 1 INCH IN DIAMETER CANNOT BE  
RULED OUT GIVEN THE 60+ KNOTS OF EFFECTIVE BULK SHEAR IN PLACE TO  
SUPPORT UPDRAFT ORGANIZATION/LONGEVITY. BY AROUND 06Z, STORMS  
TRACKING EAST TOWARDS MISSISSIPPI WILL ENCOUNTER A MOISTER LOW-LEVEL  
AIRMASS AS THEY TRAVERSE THE 850 MB JET AXIS. WHILE STORMS ARE STILL  
EXPECTED TO BE ELEVATED, THE AVAILABILITY OF DEEPER MOISTURE  
SUGGESTS THAT STORMS MAY ATTEMPT TO ROOT CLOSER TO THE SURFACE,  
POTENTIALLY OBTAINING TRANSIENT SUPERCELLULAR STRUCTURE. A COUPLE  
DAMAGING GUSTS MAY ACCOMPANY THE LONGER-LIVED, STRONGER STORMS THAT  
FORM.  
 
..SQUITIERI.. 02/25/2021  
 

 
 
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