WATCHES: Tornado Watch Number 669

WWUS20 KWNS 062210
SEL9
SPC WW 062210
NEZ000-SDZ000-070500-

URGENT - IMMEDIATE BROADCAST REQUESTED
TORNADO WATCH NUMBER 669
NWS STORM PREDICTION CENTER NORMAN OK
410 PM MDT THU AUG 6 2009

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

PARTS OF WESTERN NEBRASKA AND THE PANHANDLE
PARTS OF WESTERN AND SOUTH-CENTRAL SOUTH DAKOTA

EFFECTIVE THIS THURSDAY AFTERNOON AND EVENING FROM 410 PM UNTIL
1100 PM MDT.

TORNADOES...HAIL TO 2 INCHES IN DIAMETER...THUNDERSTORM WIND
GUSTS TO 70 MPH...AND DANGEROUS LIGHTNING ARE POSSIBLE IN THESE
AREAS.

THE TORNADO WATCH AREA IS APPROXIMATELY ALONG AND 70 STATUTE
MILES EAST AND WEST OF A LINE FROM 20 MILES EAST NORTHEAST OF
RAPID CITY SOUTH DAKOTA TO 20 MILES EAST SOUTHEAST OF SIDNEY
NEBRASKA. FOR A COMPLETE DEPICTION OF THE WATCH SEE THE
ASSOCIATED WATCH OUTLINE UPDATE (WOUS64 KWNS WOU9).

REMEMBER...A TORNADO WATCH MEANS CONDITIONS ARE FAVORABLE FOR
TORNADOES AND 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.

OTHER WATCH INFORMATION...CONTINUE...WW 666...WW 667...WW 668...

DISCUSSION...TSTMS DEVELOPING OVER ERN WY AND THE NEB PNHDL ARE
EXPECTED TO INTENSIFY THIS EVENING WHILE PROGRESSING EWD INTO A
WARM/UNSTABLE AIR MASS WITH MLCAPE OF 1500-2500 J/KG. REGIONAL VWPS
AND PROFILER DATA INDICATE THAT VERTICAL SHEAR IS ALREADY SUFFICIENT
FOR SUPERCELLS CAPABLE OF LARGE HAIL AND DAMAGING WINDS. LOW-LEVEL
SHEAR IS FORECAST TO STEADILY INCREASE THIS EVENING IN CONJUNCTION
WITH STRENGTHENING LLJ...SUGGESTING A THREAT FOR TORNADOES.

AVIATION...TORNADOES AND 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 28020.

...MEAD/HALES

+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-
To unsubscribe from WX-STORM send e-mail to LISTSERV@LISTSERV.ILLINOIS.EDU with
"unsub wx-storm" in the body of your message. For more information write cnovy@cox.net.