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656 

WWUS20 KWNS 211734

SEL9

SPC WW 211734

INZ000-220100-



URGENT - IMMEDIATE BROADCAST REQUESTED

SEVERE THUNDERSTORM WATCH NUMBER 199

NWS STORM PREDICTION CENTER NORMAN OK

135 PM EDT FRI MAY 21 2010



THE NWS STORM PREDICTION CENTER HAS ISSUED A

SEVERE THUNDERSTORM WATCH FOR PORTIONS OF



       MUCH OF INDIANA



EFFECTIVE THIS FRIDAY AFTERNOON AND EVENING FROM 135 PM UNTIL 900

PM EDT.



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 EAST AND WEST OF A LINE FROM 20 MILES EAST

NORTHEAST OF SOUTH BEND INDIANA TO 30 MILES SOUTH OF BLOOMINGTON

INDIANA.  FOR A COMPLETE DEPICTION OF THE WATCH SEE THE

ASSOCIATED WATCH OUTLINE UPDATE (WOUS64 KWNS WOU9).



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 198...



DISCUSSION...TSTMS ARE EXPECTED TO INCREASE IN COVERAGE AND

INTENSITY THIS AFTERNOON AHEAD OF COMPACT MIDLEVEL TROUGH AND

ASSOCIATED SURFACE FRONT.  WHILE CLOUDINESS HAS LIMITED DIABATIC

HEATING...BOUNDARY LAYER DEW POINTS IN THE 60S AND COOLING ALOFT

WILL CONTRIBUTE TO MLCAPE OF AROUND 1000 J/KG.  THIS INSTABILITY IN

CONJUNCTION WITH VEERING WIND PROFILES WITH HEIGHT AND 30-35 KT OF

DEEP-LAYER SHEAR WILL BE SUPPORTIVE OF ORGANIZED/ROTATING STORMS

CAPABLE OF MAINLY HAIL AND LOCALLY DAMAGING WIND GUSTS.



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 27025.





...MEAD

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