

920 

WWUS20 KWNS 120601

SEL0

SPC WW 120601

IAZ000-KSZ000-NEZ000-121200-



URGENT - IMMEDIATE BROADCAST REQUESTED

SEVERE THUNDERSTORM WATCH NUMBER 300

NWS STORM PREDICTION CENTER NORMAN OK

105 AM CDT SAT JUN 12 2010



THE NWS STORM PREDICTION CENTER HAS ISSUED A

SEVERE THUNDERSTORM WATCH FOR PORTIONS OF



       SOUTHWEST IOWA

       EXTREME NORTH CENTRAL KANSAS

       MUCH OF SOUTHERN AND EASTERN NEBRASKA



EFFECTIVE THIS SATURDAY MORNING FROM 105 AM UNTIL 700 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 65

STATUTE MILES NORTH AND SOUTH OF A LINE FROM 75 MILES WEST

SOUTHWEST OF KEARNEY NEBRASKA TO 25 MILES EAST OF OMAHA 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.



OTHER WATCH INFORMATION...THIS SEVERE THUNDERSTORM WATCH REPLACES

TORNADO WATCH NUMBER 299. WATCH NUMBER 299 WILL NOT BE IN EFFECT

AFTER 105 AM CDT.



DISCUSSION...TWO LARGE CLUSTERS OF THUNDERSTORMS WILL LIKELY PERSIST

FOR SEVERAL MORE HOURS WHILE DEVELOPING GENERALLY EWD ACROSS S

CENTRAL AND SE NEB.  THE STORMS WILL BE MAINTAINED BY AN INFLUX OF

LOW 70 DEWPOINTS ON THE NOSE OF A 40+ KT LLJ.  THOUGH DEEP-LAYER

VERTICAL SHEAR WILL BE RELATIVELY WEAK OVER ERN NEB...THE REMAINING

STRONG INSTABILITY AND SUBSTANTIAL LOW-LEVEL SHEAR SHOULD SUPPORT

SOME ORGANIZED EMBEDDED BOWING STRUCTURES WITH THE POTENTIAL FOR

DAMAGING WINDS AND ISOLATED LARGE HAIL.



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 550. MEAN STORM

MOTION VECTOR 27025.





...THOMPSON

