437  
ACUS02 KWNS 260638  
SWODY2  
SPC AC 260637  
 
DAY 2 CONVECTIVE OUTLOOK  
NWS STORM PREDICTION CENTER NORMAN OK  
1237 AM CST MON FEB 26 2024  
 
VALID 271200Z - 281200Z  
 
...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM EAST-CENTRAL  
MISSOURI INTO ILLINOIS...INDIANA...NORTHWEST OHIO AND SOUTHERN LOWER  
MICHIGAN...  
   
..SUMMARY
 
 
SCATTERED STRONG TO SEVERE THUNDERSTORMS, ASSOCIATED WITH LARGE HAIL  
(SOME NEAR 2 INCH DIAMETER), DAMAGING GUSTS, AND A FEW TORNADOES  
WILL BE POSSIBLE FROM LATE TUESDAY AFTERNOON, INTO THE EVENING AND  
OVERNIGHT FROM PARTS OF THE MID MISSISSIPPI VALLEY, AND SOUTHWESTERN  
GREAT LAKES.  
   
..MID-MS VALLEY/SOUTHWEST GREAT LAKES VICINITY
 
 
AN UPPER TROUGH OVER THE NORTHERN ROCKIES/INTERMOUNTAIN WEST WILL  
SHIFT EAST ON TUESDAY, BECOMING ORIENTED FROM THE UPPER MS VALLEY  
AND MID-MO VALLEY BY WEDNESDAY MORNING. FAST DEEP-LAYER  
SOUTHWESTERLY FLOW AHEAD OF THIS FEATURE WILL OVERSPREAD THE OZARK  
PLATEAU INTO THE GREAT LAKES. AT THE SURFACE, A LOW WILL DEEPEN AS  
IT SHIFTS EAST FROM MN TOWARD SOUTHERN ONTARIO. A COLD FRONT  
ATTENDANT TO THE LOW WILL QUICKLY SHIFT EAST/SOUTHEAST ACROSS THE  
PLAINS AND THE MID/UPPER MS VALLEY DURING THE AFTERNOON AND INTO THE  
OVERNIGHT PERIOD. INITIAL THUNDERSTORM ACTIVITY MAY DEVELOP IN WARM  
ADVECTION REGIME NEAR THE QUASI-WARM FRONT/MOISTURE GRADIENT FROM  
NORTHERN IL INTO IN/NW OH/SOUTHERN MI AROUND 21-00Z. ADDITIONAL  
ACTIVITY WILL THEN DEVELOP ALONG THE COLD FRONT AS IT DEVELOPS EAST  
AND THE MAIN UPPER WAVE EJECTS INTO THE REGION AROUND 00-03Z.  
 
WARM ADVECTION AND SOUTHERLY LOW-LEVEL FLOW AHEAD OF THE FRONT WILL  
ALLOW FOR MODEST AIRMASS MODIFICATION INTO THE MIDWEST. HOWEVER,  
FORECAST DEWPOINTS ARE ONLY EXPECTED TO REACH INTO THE 50S TO NEAR  
60 F. NEVERTHELESS, A PLUME OF STEEP MIDLEVEL LAPSE RATES WILL  
OVERSPREAD THE IL/IN/MI/OH VICINITY FROM AFTERNOON INTO THE EVENING.  
THIS WILL SUPPORT MODEST DESTABILIZATION WITH MLCAPE GENERALLY  
FORECAST TO BE LESS THAN 1000 J/KG, THOUGH A NARROW CORRIDOR OF UP  
TO 1500 J/KG MLCAPE MAY BE POSSIBLE FOR A BRIEF PERIOD AROUND 00Z.  
FORECAST SOUNDINGS ACROSS THE REGION INDICATE MOST OF AVAILABLE  
INSTABILITY WILL BE LOCATED ABOVE THE 850-700 MB LAYER.  
 
INITIAL THUNDERSTORM ACTIVITY MAY BE SLIGHTLY ELEVATED AS SOME  
FORECAST SOUNDINGS INDICATE A WARM NOSE BETWEEN 850-700 MB DURING  
LATE AFTERNOON/EARLY EVENING. NEVERTHELESS, EFFECTIVE SHEAR GREATER  
THAN 50 KT, AND ENLARGED LOW-LEVEL HODOGRAPHS BECOMING ELONGATED  
ABOVE 3 KM INDICATE INITIAL SUPERCELLS WILL BE POSSIBLE NEAR THE  
QUASI-WARM FRONT/MOISTURE GRADIENT FROM NORTHEAST IL INTO NORTHERN  
IN AND VICINITY. WITH MOST INSTABILITY FOCUSED ABOVE THE 850-700 MB  
LAYER, AND IN CONJUNCTION WITH POOR BOUNDARY-LAYER DEWPOINTS, THE  
TORNADO RISK MAY BE SOMEWHAT LOWER THAN TYPICALLY EXPECTED GIVEN  
SHEAR PROFILES IN THE 0-2 KM LAYER. NEVERTHELESS A COUPLE TORNADOES  
ARE POSSIBLE, ESPECIALLY IF GREATER MOISTURE THAN FORECAST CAN MAKE  
IT THIS FAR NORTH. LARGE HAIL, WITH A FEW INSTANCES NEAR 2 INCH  
DIAMETER, WILL BE POSSIBLE WITH ANY SEMI-DISCRETE SUPERCELLS, ALONG  
WITH DAMAGING GUSTS.  
 
ONCE LINEAR FORCING ALONG THE FRONT INCREASES IN THE 00-03Z PERIOD,  
A LINE OF STORMS IS FORECAST TO DEVELOP EAST FROM THE MID-MS VALLEY  
TOWARD THE LOWER OH VALLEY DURING THE NIGHTTIME HOURS. DAMAGING  
GUSTS WILL BE THE MAIN CONCERN WITH THIS ACTIVITY.  
 
..LEITMAN.. 02/26/2024  
 

 
 
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