

000 

WWUS20 KWNS 222024

SEL9

SPC WW 222024

NEZ000-SDZ000-WYZ000-230300-



URGENT - IMMEDIATE BROADCAST REQUESTED

SEVERE THUNDERSTORM WATCH NUMBER 729

NWS STORM PREDICTION CENTER NORMAN OK

225 PM MDT TUE JUL 22 2008



THE NWS STORM PREDICTION CENTER HAS ISSUED A

SEVERE THUNDERSTORM WATCH FOR PORTIONS OF



       PARTS OF THE NEBRASKA PANHANDLE

       PARTS OF WESTERN SOUTH DAKOTA

       PARTS OF EASTERN WYOMING



EFFECTIVE THIS TUESDAY AFTERNOON AND EVENING FROM 225 PM UNTIL

900 PM MDT.



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 60

STATUTE MILES EAST AND WEST OF A LINE FROM 80 MILES NORTHWEST OF

RAPID CITY SOUTH DAKOTA TO 40 MILES WEST OF SIDNEY NEBRASKA.  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 725...WW 726...WW

727...WW 728...



DISCUSSION...VERY UNSTABLE SELY UPSLOPE FLOW COUPLED WITH STEEP

LAPSE RATES AND VEERING SHEAR PROFILES SUPPORT DEVELOPMENT OF SLOW

MOVING SEVERE THUNDERSTORMS INCLUDING POSSIBLE SUPERCELLS.  PRIMARY

THREAT WILL BE LARGE HAIL AND DAMAGING DOWNBURST WINDS AND POSSIBLY

BRIEF TORNADOES WITH ANY SUPERCELL.



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 550. MEAN STORM

MOTION VECTOR 27010.





...HALES

