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WWUS20 KWNS 140359

SEL9

SPC WW 140359

MNZ000-NDZ000-SDZ000-141100-



URGENT - IMMEDIATE BROADCAST REQUESTED

SEVERE THUNDERSTORM WATCH NUMBER 469

NWS STORM PREDICTION CENTER NORMAN OK

1100 PM CDT TUE JUL 13 2010



THE NWS STORM PREDICTION CENTER HAS ISSUED A

SEVERE THUNDERSTORM WATCH FOR PORTIONS OF



       NORTHWEST MINNESOTA

       CENTRAL AND EASTERN NORTH DAKOTA

       NORTHWEST SOUTH DAKOTA



EFFECTIVE THIS TUESDAY NIGHT AND WEDNESDAY MORNING FROM 1100 PM

UNTIL 600 AM CDT.



HAIL TO 3 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 EAST AND WEST OF A LINE FROM 20 MILES NORTHWEST OF

HALLOCK MINNESOTA TO 50 MILES WEST SOUTHWEST OF MOBRIDGE SOUTH

DAKOTA.  FOR A COMPLETE DEPICTION OF THE WATCH SEE THE ASSOCIATED

WATCH OUTLINE UPDATE (WOUS64 KWNS WOU9).



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.



DISCUSSION...LARGE SCALE FORCING ASSOCIATED WITH UPPER TROUGH OVER

MT HAS RECENTLY SPREAD INTO ND. STORMS ARE EXPECTED TO INCREASE IN

COVERAGE AND INTENSITY THROUGH THE OVERNIGHT HOURS. GIVEN THE VERY

STRONG DEEP LAYER SHEAR AT 60-70 KT AND MODERATE INSTABILITY...

INTENSE SUPERCELLS ARE ANTICIPATED. ALTHOUGH STORMS WILL LIKELY

POSSESS STRONG MID LEVEL ROTATION...THE STORMS ARE EXPECTED TO BE

LOCATED MOSTLY BEHIND AN EASTWARD MOVING FRONT. WHILE A BRIEF

TORNADO IS POSSIBLE...THE MAIN THREAT SHOULD BE VERY LARGE HAIL AND

DAMAGING WINDS.



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

TO 3 INCHES. EXTREME TURBULENCE AND SURFACE WIND GUSTS TO 70

KNOTS. A FEW CUMULONIMBI WITH MAXIMUM TOPS TO 500. MEAN STORM

MOTION VECTOR 27030.





...IMY

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