

636 

WWUS20 KWNS 010224

SEL4

SPC WW 010224

IAZ000-ILZ000-010900-



URGENT - IMMEDIATE BROADCAST REQUESTED

SEVERE THUNDERSTORM WATCH NUMBER 124

NWS STORM PREDICTION CENTER NORMAN OK

925 PM CDT SAT MAR 31 2012



THE NWS STORM PREDICTION CENTER HAS ISSUED A

SEVERE THUNDERSTORM WATCH FOR PORTIONS OF



       EAST CENTRAL IOWA

       NORTHWEST ILLINOIS



EFFECTIVE THIS SATURDAY NIGHT AND SUNDAY MORNING FROM 925 PM

UNTIL 400 AM CDT.



HAIL TO 1.5 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 55

STATUTE MILES NORTH AND SOUTH OF A LINE FROM 5 MILES SOUTHWEST OF

CEDAR RAPIDS IOWA TO 5 MILES EAST NORTHEAST OF MARSEILLES

ILLINOIS.  FOR A COMPLETE DEPICTION OF THE WATCH SEE THE

ASSOCIATED WATCH OUTLINE UPDATE (WOUS64 KWNS WOU4).



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 123...



DISCUSSION...AREA OF TSTMS RELATED TO LOW-LEVEL WAA WILL SPREAD

EWD/ESEWD FROM ERN IA INTO NW IL OVERNIGHT.  A FEED OF MUCAPE

APPROACHING 1000 J/KG AND SUBSTANTIAL CLOUD-LAYER VERTICAL SHEAR

WILL SUPPORT ORGANIZED STORMS AND POTENTIALLY AN ELEVATED SUPERCELL

OR TWO...WITH AN ATTENDANT RISK FOR AT LEAST ISOLATED LARGE HAIL.



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

TO 1.5 INCHES. EXTREME TURBULENCE AND SURFACE WIND GUSTS TO 60

KNOTS. A FEW CUMULONIMBI WITH MAXIMUM TOPS TO 450. MEAN STORM

MOTION VECTOR 29030.





...THOMPSON

