

467 

WWUS20 KWNS 211856

SEL8

SPC WW 211856

IAZ000-ILZ000-MOZ000-220200-



URGENT - IMMEDIATE BROADCAST REQUESTED

SEVERE THUNDERSTORM WATCH NUMBER 678

NWS STORM PREDICTION CENTER NORMAN OK

155 PM CDT TUE SEP 21 2010



THE NWS STORM PREDICTION CENTER HAS ISSUED A

SEVERE THUNDERSTORM WATCH FOR PORTIONS OF



       SOUTHERN IOWA

       FAR WEST-CENTRAL ILLINOIS

       NORTHERN MISSOURI



EFFECTIVE THIS TUESDAY AFTERNOON AND EVENING FROM 155 PM UNTIL

900 PM 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 65

STATUTE MILES NORTH AND SOUTH OF A LINE FROM 55 MILES NORTH OF

KANSAS CITY MISSOURI TO 20 MILES NORTHEAST OF KIRKSVILLE

MISSOURI.  FOR A COMPLETE DEPICTION OF THE WATCH SEE THE

ASSOCIATED WATCH OUTLINE UPDATE (WOUS64 KWNS WOU8).



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 676...WW 677...



DISCUSSION...TSTMS ARE EXPECTED TO INTENSIFY THIS AFTERNOON AHEAD OF

WELL-DEFINED VORTICITY MAXIMUM CURRENTLY OVER NERN KS/SERN NEB.

AMBIENT WARM SECTOR AIR MASS IS WARM AND MOIST WITH MLCAPE VALUES OF

1500-2500 J/KG.  WHILE REGION RESIDES ALONG SRN FRINGE OF STRONGER

MID AND HIGH-LEVEL FLOW ATTENDANT TO UPPER GREAT LAKES TROUGH...AREA

PROFILER DATA INDICATE SUFFICIENT DEEP SWLY SHEAR TO SUPPORT

ORGANIZED MULTICELLS AND BOWING STRUCTURES CAPABLE OF DAMAGING WINDS

AND 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 500. MEAN STORM

MOTION VECTOR 26030.





...MEAD

