

710 

WWUS20 KWNS 171904

SEL6

SPC WW 171904

COZ000-NEZ000-WYZ000-180100-



URGENT - IMMEDIATE BROADCAST REQUESTED

TORNADO WATCH NUMBER 596

NWS STORM PREDICTION CENTER NORMAN OK

100 PM MDT FRI JUL 17 2009



THE NWS STORM PREDICTION CENTER HAS ISSUED A

TORNADO WATCH FOR PORTIONS OF



       NORTHEASTERN COLORADO

       WESTERN NEBRASKA

       EXTREME SOUTHEASTERN WYOMING



EFFECTIVE THIS FRIDAY AFTERNOON AND EVENING FROM 100 PM UNTIL 700

PM MDT.



TORNADOES...HAIL TO 3 INCHES IN DIAMETER...THUNDERSTORM WIND

GUSTS TO 80 MPH...AND DANGEROUS LIGHTNING ARE POSSIBLE IN THESE

AREAS.



THE TORNADO WATCH AREA IS APPROXIMATELY ALONG AND 55 STATUTE

MILES EAST AND WEST OF A LINE FROM 15 MILES NORTHWEST OF

SCOTTSBLUFF NEBRASKA TO 55 MILES SOUTHEAST OF LIMON COLORADO.

FOR A COMPLETE DEPICTION OF THE WATCH SEE THE ASSOCIATED WATCH

OUTLINE UPDATE (WOUS64 KWNS WOU6).



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 592...WW 593...WW

594...WW 595...



DISCUSSION...STORMS ARE DEVELOPING OVER THE HIGHER TERRAIN OF SERN

WY/NRN CO...AND SHOULD ALSO DEVELOP ALONG AN OUTFLOW BOUNDARY IN ERN

CO LATER THIS AFTERNOON. THE MOIST BOUNDARY LAYER...DEWPOINTS IN THE

MID AND UPPER 50S...COMBINED WITH STEEP MID LEVEL LAPSE RATES WAS

RESULTING IN STRONG INSTABILITY...MUCAPES UP TO 3000 J/KG. THIS

AMOUNT OF INSTABILITY AND STRONGLY VEERING WIND PROFILES WILL BE

FAVORABLE FOR INTENSE SUPERCELLS. THE PRIMARY THREAT WILL BE VERY

LARGE HAIL...THOUGH STORMS NEAR THE BOUNDARY IN ERN CO/WRN NEB MAY

INGEST ENOUGH LOW LEVEL SHEAR/HELICITY FOR TORNADOES.



AVIATION...TORNADOES AND A FEW SEVERE THUNDERSTORMS WITH HAIL

SURFACE AND ALOFT TO 3 INCHES. EXTREME TURBULENCE AND SURFACE

WIND GUSTS TO 70 KNOTS. A FEW CUMULONIMBI WITH MAXIMUM TOPS TO

500. MEAN STORM MOTION VECTOR 34025.





...IMY

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