WATCHES: Severe Thunderstorm Watch Number 626

WWUS20 KWNS 210114
SEL6
SPC WW 210114
IAZ000-210700-

URGENT - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WATCH NUMBER 626
NWS STORM PREDICTION CENTER NORMAN OK
810 PM CDT MON AUG 20 2007

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

WESTERN AND CENTRAL IOWA

EFFECTIVE THIS MONDAY NIGHT AND TUESDAY MORNING FROM 810 PM UNTIL
200 AM CDT.

HAIL TO 1.5 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 25 MILES NORTH
NORTHWEST OF SPENCER IOWA TO 5 MILES EAST SOUTHEAST OF LAMONI
IOWA. FOR A COMPLETE DEPICTION OF THE WATCH SEE THE ASSOCIATED
WATCH OUTLINE UPDATE (WOUS64 KWNS WOU6).

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 622...WW 623...WW
624...WW 625...

DISCUSSION...LINEAR MCS NOW NEAR OMA SHOULD CONTINUE E INTO VERY
UNSTABLE/HI PW AIR OVER W CNTRL/SW IA...WITH AN ATTENDANT THREAT FOR
HIGH WIND/HEAVY RAIN AND POSSIBLY SVR HAIL AND/OR A BRIEF SPIN-UP
TORNADO. FARTHER N... OTHER STORMS EXPECTED TO DEVELOP/SPREAD E
INTO NW IA...WHERE SLIGHTLY STRONGER DEEP WNWLY SHEAR IS PRESENT
CLOSER TO MAIN UPR JET...BUT LOW-LVL INSTABILITY IS MORE LIMITED.
THIS ACTIVITY MAY REMAIN SEMI-DISCRETE FOR A COUPLE HOURS AND POSE A
THREAT FOR HAIL/LOCALLY DAMAGING WIND AND POSSIBLY A BRIEF TORNADO
BEFORE MERGING INTO A SMALL CLUSTER OR TWO WITH HEAVY RAIN/LOCALLY
DAMAGING WIND.

AVIATION...A FEW SEVERE THUNDERSTORMS WITH HAIL SURFACE AND ALOFT
TO 1.5 INCHES. EXTREME TURBULENCE AND SURFACE WIND GUSTS TO 60
KNOTS. A FEW CUMULONIMBI WITH MAXIMUM TOPS TO 500. MEAN STORM
MOTION VECTOR 27025.

..CORFIDI

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