

000 

WWUS20 KWNS 020201

SEL9

SPC WW 020201

NDZ000-020900-



URGENT - IMMEDIATE BROADCAST REQUESTED

SEVERE THUNDERSTORM WATCH NUMBER 789

NWS STORM PREDICTION CENTER NORMAN OK

900 PM CDT FRI AUG 1 2008



THE NWS STORM PREDICTION CENTER HAS ISSUED A

SEVERE THUNDERSTORM WATCH FOR PORTIONS OF



       WESTERN NORTH DAKOTA



EFFECTIVE THIS FRIDAY NIGHT AND SATURDAY MORNING FROM 900 PM

UNTIL 400 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 70

STATUTE MILES EAST AND WEST OF A LINE FROM 45 MILES WEST OF

BISMARCK NORTH DAKOTA TO 50 MILES NORTH OF MINOT NORTH 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.



OTHER WATCH INFORMATION...CONTINUE...WW 788...



DISCUSSION...TSTMS ARE EXPECTED TO INCREASE IN COVERAGE OVERNIGHT

WITHIN WAA REGIME ALONG NOSE OF STRENGTHENING...NOCTURNAL LLJ.  THE

COMBINATION OF STEEP LAPSE RATES...MODERATE CONVECTIVE INSTABILITY

AND 40-50 KT OF EFFECTIVE BULK SHEAR SUGGEST THE POTENTIAL FOR

SUPERCELLS AND/OR BOWING STRUCTURES CAPABLE OF DAMAGING WINDS AND

LARGE HAIL.



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.





...MEAD/CORFIDI

