

620 

WWUS20 KWNS 030141

SEL0

SPC WW 030141

IAZ000-MNZ000-SDZ000-030800-



URGENT - IMMEDIATE BROADCAST REQUESTED

SEVERE THUNDERSTORM WATCH NUMBER 650

NWS STORM PREDICTION CENTER NORMAN OK

840 PM CDT SUN AUG 2 2009



THE NWS STORM PREDICTION CENTER HAS ISSUED A

SEVERE THUNDERSTORM WATCH FOR PORTIONS OF



       PARTS OF NORTHWEST IOWA

       MUCH OF SOUTHERN MINNESOTA

       PARTS OF SOUTHEAST SOUTH DAKOTA



EFFECTIVE THIS SUNDAY NIGHT AND MONDAY MORNING FROM 840 PM UNTIL

300 AM CDT.



HAIL TO 2.5 INCHES IN DIAMETER...THUNDERSTORM WIND GUSTS TO 80

MPH...AND DANGEROUS LIGHTNING ARE POSSIBLE IN THESE AREAS.



THE SEVERE THUNDERSTORM WATCH AREA IS APPROXIMATELY ALONG AND 60

STATUTE MILES NORTH AND SOUTH OF A LINE FROM 20 MILES WEST

NORTHWEST OF SIOUX FALLS SOUTH DAKOTA TO 25 MILES EAST SOUTHEAST

OF MINNEAPOLIS MINNESOTA.  FOR A COMPLETE DEPICTION OF THE WATCH

SEE THE ASSOCIATED WATCH OUTLINE UPDATE (WOUS64 KWNS WOU0).



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 648...WW 649...



DISCUSSION...STORMS ARE INCREASING IN NUMBER AND INTENSITY IN

ADVANCE OF FAST MOVING S/W TROUGH DAKOTAS.  WITH NOW A MDTLY

UNSTABLE AND FAVORABLY SHEARED AIR MASS POTENTIAL FOR STORMS TO

BECOME SEVERE ACROSS THE WATCH AREA WITH DAMAGING WINDS BECOMING THE

PRIMARY THREAT.  SUPERCELLS ARE ALSO POSSIBLE WITH AN ENHANCED

THREAT OF LARGE HAIL/DAMAGING WINDS AND BRIEF TORNADOES.



AVIATION...A FEW SEVERE THUNDERSTORMS WITH HAIL SURFACE AND ALOFT

TO 2.5 INCHES. EXTREME TURBULENCE AND SURFACE WIND GUSTS TO 70

KNOTS. A FEW CUMULONIMBI WITH MAXIMUM TOPS TO 550. MEAN STORM

MOTION VECTOR 26040.





...HALES

