

846 

WWUS20 KWNS 042304

SEL2

SPC WW 042304

IAZ000-MNZ000-050500-



URGENT - IMMEDIATE BROADCAST REQUESTED

SEVERE THUNDERSTORM WATCH NUMBER 242

NWS STORM PREDICTION CENTER NORMAN OK

605 PM CDT FRI MAY 4 2012



THE NWS STORM PREDICTION CENTER HAS ISSUED A

SEVERE THUNDERSTORM WATCH FOR PORTIONS OF



       EAST CENTRAL AND NORTHEAST IOWA

       EXTREME SOUTHEAST MINNESOTA



EFFECTIVE THIS FRIDAY NIGHT FROM 605 PM UNTIL MIDNIGHT CDT.



HAIL TO 2 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 45 MILES EAST

NORTHEAST OF CEDAR RAPIDS IOWA TO 35 MILES SOUTHWEST OF MASON

CITY IOWA.  FOR A COMPLETE DEPICTION OF THE WATCH SEE THE

ASSOCIATED WATCH OUTLINE UPDATE (WOUS64 KWNS WOU2).



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 238...WW 239...WW

240...WW 241...



DISCUSSION...WELL-DEVELOPED BOWING MCS WITH COMMA HEAD/MCV STRUCTURE

WILL LIKELY PERSIST AND MOVE ESEWD THROUGH LATE EVENING/EARLY

TONIGHT INTO NE IA.  A NW-SE ORIENTED FRONTAL SEGMENT ACROSS FAR NE

IA WILL TEND TO LIMIT THE NE EXTENT OF THE SEVERE STORM

THREAT...WHILE THE STORMS ARE MAINTAINED BY A FEED OF MODERATE

INSTABILITY S OF THE BOUNDARY ACROSS IA.  DAMAGING WINDS WILL BE THE

MAIN CONCERN...AND LARGE HAIL WILL ALSO BE POSSIBLE WITH THE MORE

INTENSE UPDRAFTS THIS EVENING.



AVIATION...A FEW SEVERE THUNDERSTORMS WITH HAIL SURFACE AND ALOFT

TO 2 INCHES. EXTREME TURBULENCE AND SURFACE WIND GUSTS TO 60

KNOTS. A FEW CUMULONIMBI WITH MAXIMUM TOPS TO 500. MEAN STORM

MOTION VECTOR 30035.





...THOMPSON

