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531 

WWUS20 KWNS 230101

SEL7

SPC WW 230101

IAZ000-MNZ000-NEZ000-SDZ000-230900-



URGENT - IMMEDIATE BROADCAST REQUESTED

SEVERE THUNDERSTORM WATCH NUMBER 387

NWS STORM PREDICTION CENTER NORMAN OK

800 PM CDT TUE JUN 22 2010



THE NWS STORM PREDICTION CENTER HAS ISSUED A

SEVERE THUNDERSTORM WATCH FOR PORTIONS OF



       EXTREME NORTHWEST IOWA

       SOUTHWEST MINNESOTA

       FAR NORTHEAST NEBRASKA

       CENTRAL AND EASTERN SOUTH DAKOTA



EFFECTIVE THIS TUESDAY NIGHT AND WEDNESDAY MORNING FROM 800 PM

UNTIL 400 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 80

STATUTE MILES NORTH AND SOUTH OF A LINE FROM 45 MILES WEST

SOUTHWEST OF PIERRE SOUTH DAKOTA TO 30 MILES NORTH OF WORTHINGTON

MINNESOTA.  FOR A COMPLETE DEPICTION OF THE WATCH SEE THE

ASSOCIATED WATCH OUTLINE UPDATE (WOUS64 KWNS WOU7).



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 382...WW 383...WW

385...WW 386...



DISCUSSION...A BAND OF SEVERE STORMS IN SWRN SD ARE EXPECTED TO

SPREAD NEWD THIS EVENING...WITH LARGE HAIL THE MAIN THREAT IN THE

MODERATELY UNSTABLE ENVIRONMENT. HOWEVER...APPROACHING UPPER TROUGH

AND LINE OF CONVECTION IN WRN SD ARE EXPECTED TO RACE EWD LATER

TONIGHT WITH A HIGH CHANCE FOR A LINEAR MCS. THE POSSIBILITY EXISTS

FOR  WIDESPREAD DAMAGING WINDS SPREADING EWD ACROSS THE WW...

ESPECIALLY AFTER 04Z.



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 25035.





...IMY

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