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WWUS20 KWNS 052154

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URGENT - IMMEDIATE BROADCAST REQUESTED

SEVERE THUNDERSTORM WATCH NUMBER 600

NWS STORM PREDICTION CENTER NORMAN OK

450 PM CDT TUE JUL 5 2011



THE NWS STORM PREDICTION CENTER HAS ISSUED A

SEVERE THUNDERSTORM WATCH FOR



       A SMALL PART OF NORTHEAST COLORADO

       WESTERN IOWA

       NORTHERN KANSAS

       PARTS OF NORTHWEST MISSOURI

       CENTRAL AND SOUTHERN NEBRASKA



EFFECTIVE THIS TUESDAY AFTERNOON AND WEDNESDAY MORNING FROM 450

PM UNTIL 100 AM 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 65

STATUTE MILES NORTH AND SOUTH OF A LINE FROM 30 MILES NORTH

NORTHEAST OF SAINT JOSEPH MISSOURI TO 35 MILES NORTHWEST OF

IMPERIAL NEBRASKA.  FOR A COMPLETE DEPICTION OF THE WATCH SEE THE

ASSOCIATED WATCH OUTLINE UPDATE (WOUS64 KWNS WOU0).



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.



DISCUSSION...BAND OF ELEVATED TSTMS IN CNTRL/ERN NEB HAS BEEN

PRESENT SINCE EARLIER TODAY AND APPEARS TO BE BASED AROUND 800-700

MB.  THE STORMS SHOULD BECOME INCREASINGLY SFC-BASED OVER THE NEXT

FEW HOURS AS SFC HEATING CONTINUES IN AREA ALONG AND S OF STALLED

W/E BOUNDARY LOCATED BENEATH THE BAND OF STORMS.  30-40 KT NWLY DEEP

SHEAR...MODEST BUT SUSTAINED LOW LVL ELY FLOW...AND PRESENCE OF

AMPLE MOISTURE/DEEP EML SUGGEST POSSIBILITY FOR A FEW SUPERCELLS

WITH LARGE HAIL/DMGG WIND AND POSSIBLY A TORNADO.  THE STORMS SHOULD

MERGE INTO ONE OR TWO SE-MOVING MCSS THAT EXTEND THE SVR THREAT INTO

NRN KS/NW MO.  OTHER STORMS MAY FORM IN STRONGLY HEATED UPSLOPE

ENVIRONMENT INVOF FRONT AND PRE-FRONTAL CONFLUENCE AXES IN CNTRL/WRN

NEB AND NW KS...WHERE VERY STEEP LOW LVL LAPSE RATES MAY COMPENSATE

FOR SOMEWHAT WEAKER DEEP SHEAR TO YIELD SCTD STORMS WITH SVR

WIND/HAIL.



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 31020.





...CORFIDI

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