

000 

WWUS20 KWNS 212014

SEL6

SPC WW 212014

COZ000-KSZ000-NEZ000-220500-



URGENT - IMMEDIATE BROADCAST REQUESTED

TORNADO WATCH NUMBER 156

NWS STORM PREDICTION CENTER NORMAN OK

310 PM CDT SAT APR 21 2007



THE NWS STORM PREDICTION CENTER HAS ISSUED A

TORNADO WATCH FOR PORTIONS OF



       EASTERN COLORADO

       WESTERN KANSAS

       SOUTHWEST NEBRASKA



EFFECTIVE THIS SATURDAY AFTERNOON FROM 310 PM UNTIL MIDNIGHT CDT.



TORNADOES...HAIL TO 2.5 INCHES IN DIAMETER...THUNDERSTORM WIND

GUSTS TO 70 MPH...AND DANGEROUS LIGHTNING ARE POSSIBLE IN THESE

AREAS.



THE TORNADO WATCH AREA IS APPROXIMATELY ALONG AND 80 STATUTE

MILES EAST AND WEST OF A LINE FROM 40 MILES WEST NORTHWEST OF

MCCOOK NEBRASKA TO 20 MILES WEST OF LIBERAL KANSAS.  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 154...WW 155...



DISCUSSION...TSTMS EXPECTED TO FORM IN THE NEXT HOUR OR SO ALONG LEE

TROUGH/DRY LINE SEGMENTS IN ERN CO/NE NM.  STORMS SHOULD QUICKLY

BECOME SUPERCELLS AND POSE A THREAT FOR TORNADOES/LARGE HAIL AS THEY

MOVE TOWARD HEATED/INCREASINGLY MOIST ENVIRONMENT ALONG WRN EDGE OF

STRATOCU FIELD IN WRN KS.  ARRIVAL OF STRENGTHENING WIND FIELD AND

LARGE SCALE ASCENT WITH POTENT NM UPR VORT WILL FAVOR EVENTUAL

DEVELOPMENT OF BROKEN LINES OF SUPERCELLS.  BUT STRENGTH OF LOW

LEVEL SHEAR AND POTENTIAL INCREASE IN SAME WITH NOCTURNAL DECOUPLING

OF LLJ MAY EXTEND TORNADO THREAT INTO MID/LATE EVENING IN ERN PARTS

OF WW.



AVIATION...TORNADOES AND 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

500. MEAN STORM MOTION VECTOR 22040.





...CORFIDI

