AREAS AFFECTED...EAST CENTRAL-SERN IL AND WRN IND
CONCERNING...SEVERE THUNDERSTORM WATCH 543...
VALID 312035Z - 312130Z
THE SEVERE WEATHER THREAT FOR SEVERE THUNDERSTORM WATCH 543
CONTINUES.
SUMMARY...TSTMS WILL CONTINUE TO DEVELOP ALONG THE COLD FRONT AS IT
ADVANCES SSEWD THROUGH EAST CENTRAL IL AND WEST CENTRAL IND LATE
THIS AFTERNOON...WITH ADDITIONAL STORMS FORMING ALONG THE RETREATING
OUTFLOW BOUNDARY IN SWRN IND. HAIL AND STRONG WIND GUSTS WILL
REMAIN THE PRIMARY SEVERE WEATHER THREATS.
COUNTIES ACROSS THE FAR NWRN EXTENT OF THIS WW COULD BE CANCELLED
EARLY...WHILE LOCAL AREAL EXTENSION OF THIS WATCH MAY BE NEEDED
ACROSS CENTRAL IND AS THE AIR MASS DESTABILIZES EWD.
DISCUSSION...TRENDS IN REGIONAL RADAR IMAGERY SUGGEST THE NRN EXTENT
FOR NEW TSTM DEVELOPMENT HAS SHIFTED A LITTLE SSEWD FROM MCLEAN
COUNTY IL TO BENTON COUNTY IND. IF THIS TREND PERSISTS...THEN THE
COUNTIES IN THE NWRN EXTENT OF THIS WATCH COULD BE LOCALLY CANCELLED
EARLY.
OTHERWISE...ADDITIONAL SURFACE HEATING HAS ALLOWED TEMPERATURES TO
REACH THE UPPER 90S TO NEAR 100 F IN EAST CENTRAL- SERN IL TO THE
IL/IND BORDER. THIS HEATING HAS OCCURRED TO THE WEST OF AN OLD
OUTFLOW BOUNDARY THAT HAS BEEN RETREATING NEWD DURING THE LAST FEW
HOURS AND AT 2015Z EXTENDED FROM SRN FORD COUNTY IL TO LAWRENCE
COUNTY IND. MLCAPE OF 2000-2500 J/KG ACROSS MUCH OF THE WATCH AND
DESTABILIZATION WITH EWD EXTENT OVER CENTRAL IND COMBINED WITH
EFFECTIVE BULK SHEAR OF 30-45 KT WILL SUPPORT MULTICELL AND
SUPERCELL DEVELOPMENT YET THIS AFTERNOON. IN ADDITION TO A HAIL
THREAT...THE STRONG SURFACE HEATING HAS FURTHER STEEPENED LOW LEVEL
LAPSE RATES WITH TEMPERATURE/DEWPOINT SPREADS OF 30-35 DEGREES
ENHANCING THE THREAT FOR STRONGER WIND GUSTS. THIS POTENTIAL IS
FURTHER SUPPORTED BY DCAPE VALUES THAT ARE AROUND 1500 J/KG FROM
CENTRAL/SRN IND TO ERN IL.
..PETERS.. 07/31/2012
...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT...
ATTN...WFO...LMK...IWX...IND...PAH...LOT...ILX...LSX...
LAT...LON 40288954 40778910 40988808 40808707 40588622 40028594
39368561 38838564 38548672 38548808 38718855 40288954
