WATCHES: Severe Thunderstorm Watch Number 503

WWUS20 KWNS 222249
SEL3
SPC WW 222249
MNZ000-NDZ000-SDZ000-230600-

URGENT - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WATCH NUMBER 503
NWS STORM PREDICTION CENTER NORMAN OK
545 PM CDT SUN JUL 22 2012

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

EXTREME WESTERN MINNESOTA
SOUTHEAST NORTH DAKOTA
NORTHERN AND NORTHEAST SOUTH DAKOTA

EFFECTIVE THIS SUNDAY AFTERNOON AND MONDAY MORNING FROM 545 PM
UNTIL 100 AM CDT.

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 40
STATUTE MILES NORTH AND SOUTH OF A LINE FROM 45 MILES WEST OF
MOBRIDGE SOUTH DAKOTA TO 10 MILES NORTH OF ORTONVILLE MINNESOTA.
FOR A COMPLETE DEPICTION OF THE WATCH SEE THE ASSOCIATED WATCH
OUTLINE UPDATE (WOUS64 KWNS WOU3).

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 502...

DISCUSSION...SEVERAL ROBUST STORMS HAVE ERUPTED ALONG A SLOW MOVING
COLD FRONT ALIGNED WITH THE ND/SD BORDER LATE THIS AFTERNOON.
DESPITE PRONOUNCED MID LEVEL WARM LAYER...SUFFICIENT BOUNDARY LAYER
HEATING AND COMBINATION OF PERSISTENT CONVERGENCE ALONG THE FRONT
AND MOIST AXIS IN THIS AREA...AS WELL AS SUBTLE HEIGHT FALLS
ASSOCIATED WITH AN UPPER SHORT WAVE TROUGH IN CANADA...HAVE ALL
CONTRIBUTED TO THE RECENT INCREASE IN STORM DEVELOPMENT AND
COVERAGE. MODEL GUIDANCE IS NOT CONSISTENT WITH THIS CURRENT
DEVELOPMENT SUGGESTING GREATER UNCERTAINTY IN BOTH STORM PERSISTENCE
AND EVOLUTION. HOWEVER...MAGNITUDE OF CAPE AHEAD OF THE FRONT AND
ONGOING ACTIVITY...ALONG WITH MODEST EFFECTIVE SHEAR SUPPORTIVE OF
SUPERCELL STORM STRUCTURE AND UPDRAFT PERSISTENCE...WARRANT THE
ISSUANCE OF A WATCH. THESE STORMS WILL HAVE THE POTENTIAL TO PRODUCE
HAIL OF 1-2 INCHES IN DIAMETER AND DOWNBURST WINDS TO 60KT.

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 600. MEAN STORM
MOTION VECTOR 30020.


...CARBIN

+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-
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.