

770 

WWUS20 KWNS 170412

SEL1

SPC WW 170412

NDZ000-SDZ000-171000-



URGENT - IMMEDIATE BROADCAST REQUESTED

SEVERE THUNDERSTORM WATCH NUMBER 331

NWS STORM PREDICTION CENTER NORMAN OK

1110 PM CDT WED JUN 16 2010



THE NWS STORM PREDICTION CENTER HAS ISSUED A

SEVERE THUNDERSTORM WATCH FOR PORTIONS OF



       SOUTHERN NORTH DAKOTA

       NORTHERN SOUTH DAKOTA



EFFECTIVE THIS WEDNESDAY NIGHT AND THURSDAY MORNING FROM 1110 PM

UNTIL 500 AM CDT.



HAIL TO 2 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 60

STATUTE MILES EAST AND WEST OF A LINE FROM 30 MILES NORTH

NORTHWEST OF JAMESTOWN NORTH DAKOTA TO 30 MILES EAST SOUTHEAST OF

PIERRE SOUTH DAKOTA.  FOR A COMPLETE DEPICTION OF THE WATCH SEE

THE ASSOCIATED WATCH OUTLINE UPDATE (WOUS64 KWNS WOU1).



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 326...WW 327...WW

329...WW 330...



DISCUSSION...SMALL COMPLEX OF INTENSE AND LONG-LIVED STORMS REMAINS

ANCHORED ALONG THE WARM FRONT ACROSS SD LATE THIS EVENING. THERE IS

SOME INDICATION IN REFLECTIVITY TRENDS THAT A SEVERE MCS MAY BE

EVOLVING...WITH SOME POTENTIAL TO BEGIN TO FORWARD PROPAGATE. THIS

ACTIVITY EXISTS IN A VERY UNSTABLE ENVIRONMENT AND LIFT ACROSS THE

REGION SHOULD PERSIST AS HEIGHT FALLS DEVELOP EAST FROM THE NRN HIGH

PLAINS AND NOCTURNAL LOW LEVEL JET CONTINUES TO INTENSIFY. SHEAR

WILL CONTINUE TO SUPPORT STORM ORGANIZATION WITH HIGH WINDS AND

LARGE HAIL BEING THE PRIMARY SEVERE WEATHER THREATS. EXTREME

RAINFALL WILL ALSO REMAIN A DANGER...ESPECIALLY FROM

BACKBUILDING/TRAINING CONVECTION DEVELOPING ALONG FLANKING OUTFLOWS

ORIENTED FAVORABLY WITH LOW LEVEL MASS AND MOISTURE INFLOW.



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

TO 2 INCHES. EXTREME TURBULENCE AND SURFACE WIND GUSTS TO 70

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

MOTION VECTOR 23025.





...CARBIN

