

000 

WWUS20 KWNS 302108

SEL5

SPC WW 302108

NDZ000-SDZ000-310400-



URGENT - IMMEDIATE BROADCAST REQUESTED

SEVERE THUNDERSTORM WATCH NUMBER 775

NWS STORM PREDICTION CENTER NORMAN OK

310 PM MDT WED JUL 30 2008



THE NWS STORM PREDICTION CENTER HAS ISSUED A

SEVERE THUNDERSTORM WATCH FOR PORTIONS OF



       WESTERN NORTH DAKOTA

       NORTHWEST SOUTH DAKOTA



EFFECTIVE THIS WEDNESDAY AFTERNOON AND EVENING FROM 310 PM UNTIL

1000 PM MDT.



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 75

STATUTE MILES EAST AND WEST OF A LINE FROM 65 MILES NORTHWEST OF

MINOT NORTH DAKOTA TO 95 MILES SOUTH OF LEMMON SOUTH DAKOTA.  FOR

A COMPLETE DEPICTION OF THE WATCH SEE THE ASSOCIATED WATCH

OUTLINE UPDATE (WOUS64 KWNS WOU5).



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 774...



DISCUSSION...HIGH-BASED CONVECTION IS DEVELOPING ALONG A PRE-FRONTAL

TROUGH FROM WRN ND INTO NW SD.  THIS ACTIVITY WILL LIKELY INCREASE

IN COVERAGE/INTENSITY THROUGH THE AFTERNOON/EVENING...WITH

SUPERCELLS POSSIBLE GIVEN 40-50 KT EFFECTIVE BULK SHEAR AND MODERATE

INSTABILITY.  LARGE HAIL AND DAMAGING WINDS WILL BE THE MAIN

THREATS.  STORMS SHOULD SPREAD ESEWD ACROSS ND TOWARD THE INCREASING

MOISTURE/INSTABILITY ACROSS CENTRAL SD...WHERE ANOTHER WATCH COULD

BE NEEDED LATER THIS EVENING.



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 29025.





...THOMPSON

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