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WWUS20 KWNS 011916

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URGENT - IMMEDIATE BROADCAST REQUESTED

SEVERE THUNDERSTORM WATCH NUMBER 787

NWS STORM PREDICTION CENTER NORMAN OK

315 PM EDT FRI AUG 1 2008



THE NWS STORM PREDICTION CENTER HAS ISSUED A

SEVERE THUNDERSTORM WATCH FOR PORTIONS OF



       NORTHERN INDIANA

       EXTREME SOUTHWEST LOWER MICHIGAN

       NORTHWEST OHIO



EFFECTIVE THIS FRIDAY AFTERNOON AND EVENING FROM 315 PM UNTIL 900

PM EDT.



HAIL TO 1.5 INCHES IN DIAMETER...THUNDERSTORM WIND GUSTS TO 80

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 25 MILES WEST

NORTHWEST OF SOUTH BEND INDIANA TO 30 MILES NORTH NORTHEAST OF

COLUMBUS OHIO.  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 785...WW 786...



DISCUSSION...THUNDERSTORMS SHOULD CONTINUE TO DEVELOP AND INTENSIFY

ACROSS PARTS OF OH...IND...AND LOWER MI THROUGH THE AFTERNOON HOURS

AS HEATING COMBINES WITH VERY MOIST AIR MASS AND THIS AIR IS THEN

LIFTED BY APPROACH OF STRENGTHENING SHORT WAVE TROUGH.

CURRENTLY...AIR MASS IS VERY UNSTABLE WITH MLCAPE VALUES IN EXCESS

OF 3000 J/KG ACROSS WRN PARTS OF NRN IND. ACTIVITY CURRENTLY

DEVELOPING ON LAKE BREEZE AND WEAK LOW LEVEL CONFLUENCE ZONE WILL

LIKELY STRUGGLE TO ORGANIZE AT FIRST GIVEN MARGINAL EFFECTIVE SHEAR.

HOWEVER...WITH TIME...SHEAR AND FORCING INCREASE THROUGH LATE

AFTERNOON. EXPECT STORMS TO BECOME BETTER ORGANIZED AS THIS OCCURS

AND BEGIN TO TAKE ON MORE SUPERCELLULAR CHARACTERISTICS. GIVEN

MAGNITUDE OF INSTABILITY AND POTENTIAL FOR STRONGER LARGER SCALE

FORCING WITH THE TROUGH...SEVERAL ROUNDS OF SEVERE STORMS APPEAR

POSSIBLE OVER THIS AREA INTO THE EVENING.



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

TO 1.5 INCHES. EXTREME TURBULENCE AND SURFACE WIND GUSTS TO 70

KNOTS. A FEW CUMULONIMBI WITH MAXIMUM TOPS TO 500. MEAN STORM

MOTION VECTOR 32025.





...CARBIN

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