

879 

WWUS20 KWNS 130316

SEL5

SPC WW 130316

NDZ000-SDZ000-131000-



URGENT - IMMEDIATE BROADCAST REQUESTED

SEVERE THUNDERSTORM WATCH NUMBER 605

NWS STORM PREDICTION CENTER NORMAN OK

1020 PM CDT THU AUG 12 2010



THE NWS STORM PREDICTION CENTER HAS ISSUED A

SEVERE THUNDERSTORM WATCH FOR PORTIONS OF



       SOUTH CENTRAL NORTH DAKOTA

       NORTH CENTRAL SOUTH DAKOTA



EFFECTIVE THIS THURSDAY NIGHT AND FRIDAY MORNING FROM 1020 PM

UNTIL 500 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 80

STATUTE MILES EAST AND WEST OF A LINE FROM 40 MILES NORTH OF

BISMARCK NORTH DAKOTA TO 75 MILES SOUTHWEST OF ABERDEEN 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 604...



DISCUSSION...MCS OVER SW ND/NW SD WILL LIKELY PERSIST AND MOVE EWD

THROUGH THE OVERNIGHT HOURS ALONG A CORRIDOR OF REMAINING

MODERATE-STRONG INSTABILITY AND FORCING FOR ASCENT IN ADVANCE OF THE

PRIMARY EJECTING SHORTWAVE TROUGH FROM WY.  THE STEEP LAPSE RATES

ALOFT AND EFFECTIVE BULK SHEAR OF 40-50 KT WILL SUPPORT A CONTINUED

THREAT FOR 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 27035.





...THOMPSON

