

867 

WWUS20 KWNS 292100

SEL5

SPC WW 292100

COZ000-KSZ000-NEZ000-300400-



URGENT - IMMEDIATE BROADCAST REQUESTED

SEVERE THUNDERSTORM WATCH NUMBER 235

NWS STORM PREDICTION CENTER NORMAN OK

400 PM CDT SAT MAY 29 2010



THE NWS STORM PREDICTION CENTER HAS ISSUED A

SEVERE THUNDERSTORM WATCH FOR PORTIONS OF



       NORTHEAST COLORADO

       SMALL PART OF NORTHWEST KANSAS

       LARGE PART OF CENTRAL AND WESTERN NEBRASKA



EFFECTIVE THIS SATURDAY AFTERNOON AND EVENING FROM 400 PM UNTIL

1100 PM 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 90

STATUTE MILES EAST AND WEST OF A LINE FROM 30 MILES NORTH

NORTHEAST OF AINSWORTH NEBRASKA TO 50 MILES SOUTH SOUTHEAST OF

AKRON COLORADO.  FOR A COMPLETE DEPICTION OF THE WATCH SEE THE

ASSOCIATED WATCH OUTLINE UPDATE (WOUS64 KWNS WOU5).



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 232...WW 233...WW 234...



DISCUSSION...AIR MASS ALONG/E OF COLD FRONT NOW VERY UNSTABLE AND

ONLY WEAKLY CAPPED.  WITH APPROACH OF S/WV TROUGH FROM CENTRAL

ROCKIES...AND CONVERGENCE...SEVERE THUNDERSTORMS WILL INITIALIZE

VICINITY COLD FRONT NEB.  EVENTUALLY UPSLOPE WILL DEEPEN

SUFFICIENTLY N OF FRONT IN NERN CO FOR ADDITIONAL THUNDERSTORM

DEVELOPMENT.  SHEAR AND STEEP LAPSE RATES SUPPORT BOTH MULTICELLULAR

AND ISOLATED SUPERCELLS. WHILE BRIEF TORNADOES WILL BE POSSIBLE WITH

ANY SUPERCELL...LARGE HAIL IS PRIMARY THREAT.



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 500. MEAN STORM

MOTION VECTOR 24025.





...HALES

