SPC Severe Thunderstorm Watch 583

WW 583 SEVERE TSTM IL IN KY MO 162030Z - 170400Z
URGENT - IMMEDIATE BROADCAST REQUESTED SEVERE THUNDERSTORM WATCH NUMBER 583 NWS STORM PREDICTION CENTER NORMAN OK 330 PM CDT THU AUG 16 2012 THE NWS STORM PREDICTION CENTER HAS ISSUED A SEVERE THUNDERSTORM WATCH FOR PORTIONS OF SOUTHERN ILLINOIS SOUTHERN INDIANA WESTERN KENTUCKY SOUTHEAST MISSOURI EFFECTIVE THIS THURSDAY AFTERNOON AND EVENING FROM 330 PM UNTIL 1100 PM CDT. HAIL TO 1.5 INCHES IN DIAMETER...THUNDERSTORM WIND GUSTS TO 75 MPH...AND DANGEROUS LIGHTNING ARE POSSIBLE IN THESE AREAS. THE SEVERE THUNDERSTORM WATCH AREA IS APPROXIMATELY ALONG AND 75 STATUTE MILES EAST AND WEST OF A LINE FROM 35 MILES NORTH NORTHEAST OF BLOOMINGTON INDIANA TO 40 MILES SOUTH OF PADUCAH KENTUCKY. FOR A COMPLETE DEPICTION OF THE WATCH SEE THE ASSOCIATED WATCH OUTLINE UPDATE (WOUS64 KWNS WOU3). REMEMBER...A SEVERE THUNDERSTORM WATCH MEANS CONDITIONS ARE FAVORABLE FOR SEVERE THUNDERSTORMS IN AND CLOSE TO THE WATCH AREA. PERSONS IN THESE AREAS SHOULD BE ON THE LOOKOUT FOR THREATENING WEATHER CONDITIONS AND LISTEN FOR LATER STATEMENTS AND POSSIBLE WARNINGS. SEVERE THUNDERSTORMS CAN AND OCCASIONALLY DO PRODUCE TORNADOES. OTHER WATCH INFORMATION...CONTINUE...WW 582... DISCUSSION...STORMS ARE CONSOLIDATING ALONG A COLD FRONT MOVING SEWD FROM IL/WRN IND SWWD TO MO THIS AFTERNOON. A VERY WARM AND MOIST AIRMASS AHEAD OF THE FRONT WILL RESULT IN SUFFICIENT INSTABILITY TO SUSTAIN STRONG TO SEVERE STORMS AS THE FRONT SETTLES SEWD TOWARD THE LOWER OH VALLEY AND CONFLUENCE OF THE OH/MS RIVERS THROUGH THIS EVENING. DEEP-LAYER WLY FLOW IS FORECAST TO STRENGTHEN COINCIDENT WITH THE FRONTAL ADVANCE AND SHOULD SUPPORT AND INCREASE IN STORM MOTION AND ORGANIZATION...ESPECIALLY ACROSS ERN IL AND SRN IND. SLIGHTLY WEAKER MID LEVEL FLOW WITH SWD/SWWD EXTENT WILL LIKELY BE COMPENSATED FOR BY GREATER DESTABILIZATION IN THESE AREAS TO SUPPORT VIGOROUS STORMS WITH SOME HAIL AND SEVERE WIND POTENTIAL. AVIATION...A FEW SEVERE THUNDERSTORMS WITH HAIL SURFACE AND ALOFT TO 1.5 INCHES. EXTREME TURBULENCE AND SURFACE WIND GUSTS TO 65 KNOTS. A FEW CUMULONIMBI WITH MAXIMUM TOPS TO 600. MEAN STORM MOTION VECTOR 31030. ...CARBIN Read more

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