

884 

WWUS20 KWNS 212302

SEL1

SPC WW 212302

IAZ000-KSZ000-MOZ000-NEZ000-220600-



URGENT - IMMEDIATE BROADCAST REQUESTED

SEVERE THUNDERSTORM WATCH NUMBER 371

NWS STORM PREDICTION CENTER NORMAN OK

600 PM CDT MON JUN 21 2010



THE NWS STORM PREDICTION CENTER HAS ISSUED A

SEVERE THUNDERSTORM WATCH FOR PORTIONS OF



       SOUTHWESTERN IOWA

       NORTHEASTERN KANSAS

       NORTHWESTERN MISSOURI

       SOUTHEASTERN NEBRASKA



EFFECTIVE THIS MONDAY NIGHT AND TUESDAY MORNING FROM 600 PM UNTIL

100 AM 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 APPROXIMATELY ALONG AND 60

STATUTE MILES NORTH AND SOUTH OF A LINE FROM 30 MILES EAST

SOUTHEAST OF LAMONI IOWA TO 40 MILES SOUTHWEST OF BEATRICE

NEBRASKA.  FOR A COMPLETE DEPICTION OF THE WATCH SEE THE

ASSOCIATED WATCH OUTLINE UPDATE (WOUS64 KWNS WOU1).



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 367...WW 368...WW

369...WW 370...



DISCUSSION...STORMS ARE EXPECTED TO DEVELOP THROUGH THE EVENING

ALONG A WEAK BOUNDARY STRETCHING FROM NRN KS EWD TO THE MO/IA

BORDER... ESPECIALLY AS LOW LEVEL JET STRENGTHENS.  THE COMBINATION

OF A VERY UNSTABLE AIR MASS AND EFFECTIVE SHEAR AT 30-40 KT WILL BE

FAVORABLE FOR SUPERCELLS WITH LARGE HAIL. THE STORMS ARE LIKELY TO

TRAIN/BACKBUILD NEAR THE BOUNDARY...SO A FEW LOCATIONS MAY RECEIVE

MORE THAN ONE SEVERE STORM.  WHILE A BRIEF TORNADO MAY BE POSSIBLE

FOR THE NEXT HOUR OR SO AS STORMS FORM...THE VERY WEAK LOW LEVEL

SHEAR SUGGESTS THE TORNADO THREAT SHOULD BE LOW.



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 550. MEAN STORM

MOTION VECTOR 26020.





...IMY

