747  
ACUS03 KWNS 260835  
SWODY3  
SPC AC 260834  
 
DAY 3 CONVECTIVE OUTLOOK CORR 1  
NWS STORM PREDICTION CENTER NORMAN OK  
0234 AM CST SUN FEB 26 2017  
 
VALID 281200Z - 011200Z  
 
...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS OVER THE OZARK  
PLATEAU INTO SOUTHEASTERN MISSOURI...  
 
...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM NORTHEAST  
TEXAS NORTHEASTWARD INTO THE MIDDLE MISSISSIPPI VALLEY AND OHIO  
VALLEY...  
 
...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS SURROUNDING THE  
SLIGHT RISK...  
 
CORRECTED FOR THE MENTION OF POSSIBLE SEVERE IN THE OHIO VALLEY IN  
THE SUMMARY SECTION  
   
..SUMMARY
 
 
SEVERE THUNDERSTORMS WILL BE POSSIBLE ON TUESDAY AND TUESDAY NIGHT  
FROM EASTERN PORTIONS OF OKLAHOMA AND TEXAS EASTWARD INTO PARTS OF  
THE LOWER AND MIDDLE MISSISSIPPI VALLEY AND OHIO VALLEY.  
   
..SYNOPSIS
 
 
A LARGE-SCALE MID-LEVEL TROUGH OVER THE WESTERN U.S. WILL MOVE INTO  
THE CENTRAL STATES ON TUESDAY AS A BELT OF STRONG SOUTHWESTERLY  
500-MB FLOW INTENSIFIES FURTHER DURING THE PERIOD AS A 100-KT SPEED  
MAX MOVES TO THE LOWER MO VALLEY BY EARLY WEDNESDAY MORNING. IN THE  
LOW LEVELS, A BROAD WARM SECTOR WILL BECOME ESTABLISHED FROM THE  
CENTRAL GULF COAST STATES NORTHWARD INTO THE OH VALLEY AND BOUNDED  
ON THE NORTH WITH AN ADVANCING WARM FRONT. THE WEST EDGE OF THE  
LOW-LEVEL MOISTURE WILL LIKELY BE LOCATED OVER THE EASTERN PORTIONS  
OF TX/OK AS AN ELONGATED AREA OF LOW PRESSURE EXTENDS FROM THE  
MIDDLE MS VALLEY/GREAT LAKES SOUTHWESTWARD INTO OK/KS AND DEVELOPING  
EASTWARD INTO THE OZARKS DURING THE OVERNIGHT.  
 
...EASTERN OK/NORTHEAST TX NORTHEASTWARD INTO THE MS VALLEY AND  
LOWER OH VALLEY...  
COMPLICATED FORECAST SCENARIO WITH SIGNIFICANT UNCERTAINTY IS  
EVIDENT IN BOTH THE COVERAGE AND INTENSITY OF SEVERE THUNDERSTORMS  
ACROSS A LARGE WARM/MOIST SECTOR. STEEP 700-500 MB LAPSE RATES (7-8  
DEGREES C PER KM) ATOP LOWER TO MIDDLE 60S DEWPOINTS OVER AR AND  
DEWPOINTS NEAR 60 DEGREES F IN THE OH VALLEY WILL CONTRIBUTE TO WEAK  
TO MODERATE BUOYANCY. STRONG SHEAR PROFILES (60-70 KT EFFECTIVE  
SHEAR) WILL RESULT IN A SUPERCELL-WIND PROFILE. A WIDE ARRAY OF  
POSSIBILITIES ARE PLAUSIBLE AT THIS TIME, INCLUDING A RISK FOR  
WARM-AIR-ADVECTION STORMS DEVELOPING DURING THE LATE  
AFTERNOON/EVENING OVER PORTIONS OF AR AND THE MS VALLEY AND YIELDING  
A TORNADO AND HAIL RISK. COMPLICATING THIS SCENARIO INCLUDES A  
CIRRUS CANOPY IMPLIED BY MODEL DATA AS WELL AS THE DEGREE OF  
HEATING.  
 
A COLD FRONT IS FORECAST TO MOVE INTO THE WESTERN PORTIONS OF THE  
BROAD OUTLOOK AREA DURING THE EVENING AND OVERNIGHT AND PUSH  
EAST-SOUTHEASTWARD. THUNDERSTORMS ARE LIKELY TO DEVELOP ALONG THE  
FRONT AND SEVERE IS POSSIBLE WITH THIS ACTIVITY AS WELL. DAMAGING  
WINDS AND HAIL WILL BE THE PREDOMINATE RISKS EARLY ON WITH THIS  
ACTIVITY BEFORE UPSCALE GROWTH INTO ONE OR MORE LARGER CONVECTIVE  
LINES AND BOWING SEGMENTS YIELDS A CONTINUED WIND RISK AND PERHAPS A  
LINGERING TORNADO THREAT.  
 
..SMITH.. 02/26/2017  
 

 
 
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