URGENT - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WATCH NUMBER 555
NWS STORM PREDICTION CENTER NORMAN OK
415 PM CDT SAT JUL 31 2010

THE NWS STORM PREDICTION CENTER HAS ISSUED A
SEVERE THUNDERSTORM WATCH FOR PORTIONS OF 

       PARTS OF SOUTHWEST NORTH DAKOTA
       MUCH OF WESTERN SOUTH DAKOTA
       PARTS OF NORTHEAST WYOMING

EFFECTIVE THIS SATURDAY AFTERNOON AND EVENING FROM 415 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 70 MILES NORTHEAST OF
LEMMON SOUTH DAKOTA TO 85 MILES WEST SOUTHWEST OF RAPID CITY
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 552...WW 553...WW 554...

DISCUSSION...SCATTERED STRONG/SEVERE THUNDERSTORMS WILL DEVELOP IN
AREA OF LOW LEVEL CONVERGENCE AND MDT INSTABILITY.  WITH STEEP LAPSE
RATES DAMAGING WINDS ALONG WITH LARGE HAIL WILL BE ASSOCIATED WITH
MOST INTENSE STORMS.

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 550. MEAN STORM
MOTION VECTOR 26025.


...HALES

STATUS FOR WATCH 0557 HAS NOT BEEN ISSUED YET