

942 

WWUS20 KWNS 142028

SEL1

SPC WW 142028

IAZ000-NEZ000-150400-



URGENT - IMMEDIATE BROADCAST REQUESTED

SEVERE THUNDERSTORM WATCH NUMBER 391

NWS STORM PREDICTION CENTER NORMAN OK

330 PM CDT THU JUN 14 2012



THE NWS STORM PREDICTION CENTER HAS ISSUED A

SEVERE THUNDERSTORM WATCH FOR PORTIONS OF



       WESTERN AND NORTH-CENTRAL IOWA

       EASTERN NEBRASKA



EFFECTIVE THIS THURSDAY AFTERNOON AND EVENING FROM 330 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 60

STATUTE MILES EAST AND WEST OF A LINE FROM 40 MILES NORTHEAST OF

SPENCER IOWA TO 15 MILES SOUTH OF LINCOLN NEBRASKA.  FOR A

COMPLETE DEPICTION OF THE WATCH SEE THE ASSOCIATED WATCH OUTLINE

UPDATE (WOUS64 KWNS WOU1).



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 389...WW 390...



DISCUSSION...TSTMS ARE EXPECTED TO INCREASE IN COVERAGE AND

INTENSITY THIS AFTERNOON ALONG AND AHEAD OF COLD FRONT WHERE AIR

MASS HAS BECOME MODERATE-STRONGLY UNSTABLE WITH MLCAPE OF 2000-4000+

J/KG.  VERTICAL SHEAR WILL REMAIN RELATIVELY WEAK...BUT THE

CHARACTER OF THE THERMODYNAMIC ENVIRONMENT WILL FOSTER INTENSE

UP/DOWNDRAFTS CAPABLE OF DAMAGING WINDS AND LARGE 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 27020.





...MEAD

