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116
ACUS01 KWNS 220554
SWODY1
SPC AC 220553

DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1153 PM CST SUN DEC 21 2014

VALID 221200Z - 231200Z

...THERE IS A MRGL RISK OF SVR TSTMS ACROSS PORTIONS OF THE GULF
COAST/LOWER MISSISSIPPI VALLEY...

...SUMMARY...
ISOLATED SEVERE STORMS WILL BE POSSIBLE MONDAY INTO EARLY TUESDAY
ACROSS PARTS OF THE LOWER MISSISSIPPI VALLEY AND GULF COAST STATES.

...SYNOPSIS...
THE CENTRAL CONUS UPPER TROUGH WILL CONTINUE TO DEEPEN MONDAY AS A
500 MB 100-KT JET DIVES SOUTH FROM THE PACIFIC NORTHWEST THROUGH THE
CENTRAL/SOUTHERN ROCKIES WITH A CLOSED UPPER LOW DEVELOPING OVER THE
MID-MISSISSIPPI VALLEY. ONE PROMINENT SHORTWAVE WILL ROTATE AROUND
THE EVOLVING UPPER LOW ACROSS THE MID-MISSISSIPPI VALLEY AND GREAT
LAKES WHILE A SOUTHERN SHORTWAVE WILL BE POISED TO MOVE INTO THE
SOUTHERN PLAINS TOWARDS 12Z TUESDAY.

A SURFACE LOW INITIALLY IN THE VICINITY OF EASTERN SOUTH DAKOTA WILL
MOVE TO EASTERN IOWA BY 12Z TUESDAY AS THE ASSOCIATED COLD FRONT
MOVES EAST AND EXTENDS FROM NORTHERN ILLINOIS THROUGH WESTERN
KENTUCKY AND INTO SOUTH TEXAS BY THE END OF THE PERIOD. A WARM FRONT
WILL LIFT NORTHWARD ACROSS THE CENTRAL/EASTERN GULF STATES/LOWER
MISSISSIPPI VALLEY.

...GULF COAST/LOWER MISSISSIPPI VALLEY REGION...
SOME VARIABILITY PERSISTS AMONG NUMERICAL GUIDANCE REGARDING THE
LOCATION OF THE WARM FRONT...INITIALLY JUST SOUTH OF THE
CENTRAL/EASTERN GULF COAST...DURING THE DAY MONDAY. MOST LIKELY
SCENARIO IS FOR THE WARM FRONT TO EXTEND FROM CENTRAL/NORTHERN
MISSISSIPPI INTO SOUTHERN ALABAMA/GEORGIA BY MONDAY EVENING. NORTH
OF THE WARM FRONT...MODEST ELEVATED INSTABILITY WILL EXIST WITH
MUCAPE OF 250 TO 500 J/KG DURING THE AFTERNOON/EVENING. WITH
GENERALLY WEAK ISENTROPIC ASCENT AND LARGE-SCALE LIFT WITH THE
INITIAL SHORTWAVE REMAINING NORTH OF THE AREA...ONLY ISOLATED
THUNDERSTORMS ARE EXPECTED. EFFECTIVE BULK SHEAR OF 50-60 KTS
SUGGESTS A RISK OF MARGINALLY SEVERE HAIL/WIND WILL EXIST WITH THE
STRONGEST STORMS.

NEAR AND SOUTH OF THE WARM FRONT...LOWER TO MID 60S SURFACE DEW
POINTS WILL ADVECT NORTHWARD DURING THE DAY AND CONTRIBUTE TO MUCAPE
OF 500 TO 1000 J/KG IN THE PRESENCE OF 40-50 KNOTS OF EFFECTIVE BULK
SHEAR. LOW-LEVEL SRH WILL BE MAXIMIZED NEAR THE WARM FRONT...AND ANY
STORM THAT DEVELOPS WOULD POSE AT LEAST SOME WIND/TORNADO THREAT.
HOWEVER...WITH THE STRONGEST HEIGHT FALLS/FORCING FOR ASCENT WITH
THE SOUTHERN SHORTWAVE REMAINING UPSTREAM...THUNDERSTORMS SHOULD
REMAIN ISOLATED IN THIS AREA UNTIL AFTER 12Z TUE.

..BUNTING/MARSH.. 12/22/2014





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