

714 

WWUS20 KWNS 021155

SEL5

SPC WW 021155

ILZ000-INZ000-MOZ000-021700-



URGENT - IMMEDIATE BROADCAST REQUESTED

SEVERE THUNDERSTORM WATCH NUMBER 55

NWS STORM PREDICTION CENTER NORMAN OK

555 AM CST FRI MAR 2 2012



THE NWS STORM PREDICTION CENTER HAS ISSUED A

SEVERE THUNDERSTORM WATCH FOR PORTIONS OF



       CENTRAL ILLINOIS

       WEST CENTRAL INDIANA

       CENTRAL AND EAST CENTRAL MISSOURI



EFFECTIVE THIS FRIDAY MORNING FROM 555 AM UNTIL 1100 AM CST.



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 50

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

NORTHWEST OF FORT LEONARD WOOD MISSOURI TO 45 MILES SOUTHEAST OF

LAFAYETTE INDIANA.  FOR A COMPLETE DEPICTION OF THE WATCH SEE THE

ASSOCIATED WATCH OUTLINE UPDATE (WOUS64 KWNS WOU5).



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...THIS SEVERE THUNDERSTORM WATCH REPLACES

SEVERE THUNDERSTORM WATCH NUMBER 54. WATCH NUMBER 54 WILL NOT BE

IN EFFECT AFTER 555 AM CST.



DISCUSSION...ELEVATED STORMS...INCLUDING A SUPERCELL CLUSTER NEAR

STL...WILL CONTINUE TO MOVE ENEWD IN A ZONE OF STRONG LOW-LEVEL WAA

AND DESTABILIZATION JUST ABOVE THE SURFACE...IMMEDIATELY IN ADVANCE

OF A DEEPENING SURFACE LOW IN SW MO.  MODERATE INSTABILITY /ROOTED

NEAR 850 MB/ IS PRESENT UPSTREAM FROM THE WATCH AREA PER THE 12Z SGF

SOUNDING...AND A SIMILAR ENVIRONMENT OF STRONG CLOUD-LAYER SHEAR AND

MUCAPE AOA 1500 J/KG WILL SPREAD ACROSS CENTRAL IL/INDIANA THROUGH

THE MORNING.  LARGE HAIL WILL CONTINUE TO BE THE PRIMARY SEVERE

STORM RISK...THOUGH ISOLATED DAMAGING GUSTS WILL ALSO BE POSSIBLE.



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 24040.





...THOMPSON

