

000 

WWUS20 KWNS 030229

SEL7

SPC WW 030229

IAZ000-ILZ000-MOZ000-031000-



URGENT - IMMEDIATE BROADCAST REQUESTED

SEVERE THUNDERSTORM WATCH NUMBER 427

NWS STORM PREDICTION CENTER NORMAN OK

915 PM CDT MON JUN 2 2008



THE NWS STORM PREDICTION CENTER HAS ISSUED A

SEVERE THUNDERSTORM WATCH FOR PORTIONS OF



       SOUTHERN IOWA

       WESTERN AND CENTRAL ILLINOIS

       NORTHERN MISSOURI



EFFECTIVE THIS MONDAY NIGHT AND TUESDAY MORNING FROM 915 PM UNTIL

500 AM 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 80

STATUTE MILES NORTH AND SOUTH OF A LINE FROM 45 MILES WEST OF

LAMONI IOWA TO 10 MILES SOUTH SOUTHEAST OF DECATUR ILLINOIS.  FOR

A COMPLETE DEPICTION OF THE WATCH SEE THE ASSOCIATED WATCH

OUTLINE UPDATE (WOUS64 KWNS WOU7).



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 422...WW 423...WW

425...WW 426...



DISCUSSION...TSTMS ARE EXPECTED TO INCREASE IN BANDS ALONG THE NOSE

OF AN INCREASING SWLY LOW-LEVEL JET FROM PARTS OF SRN IA...CNTRL/NRN

MO INTO WRN IL OVERNIGHT.  STEEP MID-LEVEL LAPSE RATES ON THE ORDER

OF 8 DEG C PER KM AND EFFECTIVE SHEAR IN EXCESS OF 50 KTS SUGGESTS

THAT ELEVATED SUPERCELLS WILL GRADUALLY EVOLVE WITH LARGE HAIL

LIKELY AND PERHAPS GUSTY WINDS.



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 28025.





...RACY/THOMPSON

