698  
ACUS01 KWNS 050556  
SWODY1  
SPC AC 050555  
 
DAY 1 CONVECTIVE OUTLOOK  
NWS STORM PREDICTION CENTER NORMAN OK  
1155 PM CST SUN DEC 04 2016  
 
VALID 051200Z - 061200Z  
 
...THERE IS A SLGT RISK OF SVR TSTMS ACROSS PARTS OF THE CENTRAL  
GULF COAST REGION...  
 
...THERE IS A MRGL RISK OF SVR TSTMS ACROSS PARTS OF THE LOWER  
MISSISSIPPI VALLEY AND CENTRAL GULF COAST REGION...  
   
..SUMMARY
 
 
A FEW STRONG TO SEVERE STORMS WITH POTENTIAL FOR DAMAGING WINDS AND  
A COUPLE TORNADOES ARE POSSIBLE THIS AFTERNOON INTO TONIGHT OVER THE  
CENTRAL GULF COAST STATES.  
   
..CENTRAL GULF COAST STATES
 
 
AN UPPER-LEVEL LOW WILL MOVE INTO THE SOUTHERN PLAINS TODAY AND  
BECOME A NEGATIVELY-TILTED UPPER-LEVEL TROUGH BY AFTERNOON.  
THUNDERSTORMS ASSOCIATED WITH WARM ADVECTION WILL FORM AHEAD OF THE  
SYSTEM IN THE LOWER MISSISSIPPI VALLEY DURING THE DAY WITH ISOLATED  
CONVECTION POSSIBLE FURTHER TO THE EAST ALONG THE GULF COAST. THE  
SEVERE THREAT SHOULD REMAIN MARGINAL THIS MORNING INTO EARLY  
AFTERNOON AS THE HIGHER QUALITY LOW-LEVEL MOISTURE REMAINS OFFSHORE.  
IN THE CENTRAL GULF COAST STATES...THE STRONGER MOISTURE ADVECTION  
WILL OCCUR IN THE MID TO LATE AFTERNOON INTO EVENING AS MID-LEVEL  
HEIGHTS BEGIN TO FALL AHEAD OF THE APPROACHING SYSTEM. SURFACE  
DEWPOINTS ARE FORECAST TO INCREASE INTO THE MID TO UPPER 60S  
FAHRENHEIT THROUGH THE LATE AFTERNOON INTO THE EVENING ACROSS  
SOUTHERN MISSISSIPPI AND SOUTH-CENTRAL ALABAMA. IN ADDITION...THE  
WIND SHEAR ENVIRONMENT WILL MARKEDLY IMPROVE AS LOW-LEVEL FLOW  
STRENGTHENS LATE IN THE DAY. THIS MAY BE ENOUGH FOR A SEVERE THREAT  
DURING THE MID TO LATE AFTERNOON WITH A GRADUAL INCREASE IN THE  
SEVERE THREAT DURING THE EVENING. ANY WARM ADVECTION RELATED  
DISCRETE CELLS THAT MOVE INLAND COULD HAVE A WIND DAMAGE AND OR  
ISOLATED TORNADO THREAT.  
 
THE GREATEST SEVERE THREAT IS EXPECTED TO DEVELOP DURING THE LATE  
EVENING AND OVERNIGHT PERIOD AS LARGE-SCALE ASCENT INCREASES AHEAD  
OF THE APPROACHING UPPER-LEVEL TROUGH. SURFACE DEWPOINTS ARE  
FORECAST TO REACH THE MID 60S INTO CENTRAL ALABAMA WITH NEAR 70  
POSSIBLE AT MOBILE AS A 40 TO 55 KNOT LOW-LEVEL JET MOVES INTO THE  
CENTRAL GULF COAST STATES AFTER MIDNIGHT. THIS INCREASE IN LOW-LEVEL  
MOISTURE AND SHEAR SHOULD RESULT IN AN INCREASED TORNADO THREAT WITH  
WIND DAMAGE POSSIBLE AS CONVECTIVE COVERAGE INCREASES DURING THE 06Z  
TO 12Z TIME-FRAME ACROSS SOUTHERN MISSISSIPPI AND SOUTHERN TO  
CENTRAL ALABAMA. FORECAST SOUNDINGS SUGGEST THAT 0-3 KM STORM  
RELATIVE HELICITY WILL INCREASE INTO THE 300 TO 350 M2/S2 RANGE OVER  
THE CENTRAL PART OF THE SLIGHT RISK AREA SUGGESTING A COUPLE  
TORNADOES WILL BE POSSIBLE WITH THE DISCRETE CELLS THAT MOVE  
NORTHEASTWARD ACROSS THE SOUTHERN HALF OF ALABAMA AND THE FLORIDA  
PANHANDLE. DUE TO THE LONGER DURATION OF THE SEVERE WEATHER THREAT  
AND FOCUSED NATURE OF THE THREAT AS THE UPPER-LEVEL SYSTEM  
APPROACHES LATE TONIGHT...HAVE EXTENDED THE SLIGHT RISK AREA  
NORTHWARD TO BETWEEN BIRMINGHAM AND MONTGOMERY.  
 
..BROYLES/GLEASON.. 12/05/2016  
 

 
 
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