URGENT - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WATCH NUMBER 121
STORM PREDICTION CENTER NORMAN OK
515 PM CDT TUE APR 15 2003
THE STORM PREDICTION CENTER HAS ISSUED A
SEVERE THUNDERSTORM WATCH FOR PORTIONS OF
NORTHWEST IOWA
SOUTHWEST MINNESOTA
NORTH CENTRAL AND NORTHEASTERN NEBRASKA
SOUTHEAST SOUTH DAKOTA
EFFECTIVE THIS TUESDAY AFTERNOON AND EVENING FROM 515 PM UNTIL 1100
PM CDT.
HAIL TO 2 INCHES IN DIAMETER...THUNDERSTORM WIND GUSTS TO 70
MPH...AND DANGEROUS LIGHTNING ARE POSSIBLE IN THESE AREAS.
THE SEVERE THUNDERSTORM WATCH AREA IS ALONG AND 95 STATUTE MILES
EAST AND WEST OF A LINE FROM 35 MILES SOUTHEAST OF BROKEN BOW
NEBRASKA TO 15 MILES NORTHEAST OF BROOKINGS SOUTH DAKOTA.
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 118...WW 119...WW 120...
DISCUSSION...SEVERE THUNDERSTORMS WILL CONTINUE DEVELOPING NWD OUT
OF WRN KS/SWRN NEB AHEAD OF STRONG UPPER TROUGH NOW MOVING INTO THE
HIGH PLAINS. IN ADDITION...WEAKER VORT MAX NOW LIFTING NNEWD
TOWARDS SERN IA SHOULD ENHANCE ASCENT AND THUNDERSTORM DEVELOPMENT
SOUTH OF SURFACE FRONT WHERE SBCAPES FROM 1000-2000 J/KG ARE
CURRENTLY IN PLACE. SHEAR WILL NOT BE IMPRESSIVE...HOWEVER 0-6 KM
SHEAR FROM 35-45 KT SHOULD STILL SUFFICE FOR ORGANIZED
LINES/MULTICELL CLUSTERS WITH PRIMARY THREATS OF LARGE HAIL AND
DAMAGING WINDS.
AVIATION...A FEW SEVERE THUNDERSTORMS WITH HAIL SURFACE AND ALOFT
TO 2 INCHES. EXTREME TURBULENCE AND SURFACE WIND GUSTS TO 60
KNOTS. A FEW CUMULONIMBI WITH MAXIMUM TOPS TO 500. MEAN STORM
MOTION VECTOR 21035.