

000 

WWUS20 KWNS 211914

SEL2

SPC WW 211914

NDZ000-220400-



URGENT - IMMEDIATE BROADCAST REQUESTED

SEVERE THUNDERSTORM WATCH NUMBER 282

NWS STORM PREDICTION CENTER NORMAN OK

215 PM CDT MON MAY 21 2007



THE NWS STORM PREDICTION CENTER HAS ISSUED A

SEVERE THUNDERSTORM WATCH FOR PORTIONS OF



       A LARGE PART OF NORTH DAKOTA



EFFECTIVE THIS MONDAY AFTERNOON AND EVENING FROM 215 PM UNTIL

1100 PM CDT.



HAIL TO 2.5 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 85

STATUTE MILES EAST AND WEST OF A LINE FROM 75 MILES NORTHEAST OF

MINOT NORTH DAKOTA TO 25 MILES EAST OF LEMMON SOUTH DAKOTA.  FOR

A COMPLETE DEPICTION OF THE WATCH SEE THE ASSOCIATED WATCH

OUTLINE UPDATE (WOUS64 KWNS WOU2).



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...TSTMS/POSSIBLE SUPERCELLS EXPECTED TO FORM IN THE NEXT

HOUR OR TWO ALONG NNE/SSW PREFRONTAL TROUGH IN WRN PART OF WW.

OTHER STORMS MAY FORM A BIT LATER ALONG ACTUAL COLD FRONT IN FAR WRN

ND.  STRENGTHENING DEEP SSWLY SHEAR DOWNSTREAM FROM APPROACHING UPR

LOW...COUPLED WITH CONTINUED SFC HEATING...WILL CREATE SETUP

FAVORABLE FOR A FEW SUSTAINED SUPERCELLS WITH LARGE HAIL/HIGH WIND

AND POSSIBLY A TORNADO.  ACTIVITY SHOULD EVOLVE FAIRLY QUICKLY INTO

A BROKEN LINE...WITH EMBEDDED LEWP STRUCTURES CONTINUING TO POSE A

THREAT FOR HAIL/WIND AND PERHAPS A TORNADO.



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

TO 2.5 INCHES. EXTREME TURBULENCE AND SURFACE WIND GUSTS TO 60

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

MOTION VECTOR 22030.





...CORFIDI

