AREAS AFFECTED...IND...WRN OH...CNTRL IL
CONCERNING...SEVERE POTENTIAL...SEVERE THUNDERSTORM WATCH LIKELY
VALID 071509Z - 071715Z
PROBABILITY OF WATCH ISSUANCE...80 PERCENT
SUMMARY...ONGOING/LARGELY ELEVATED TSTM CLUSTERS SHOULD BECOME
INCREASINGLY SURFACE-BASED AS DOWNSTREAM AIR MASS HEATS AND
DESTABILIZES. STRONG DEEP-LAYER SPEED SHEAR WILL BE SUFFICIENT FOR
EMBEDDED ORGANIZED UPDRAFTS AND PROBABLE UPSCALE GROWTH ALONG THE
LEADING FLANK WITH A PRIMARY THREAT OF DAMAGING WINDS.
DISCUSSION...ALTHOUGH CONVECTIVE OUTFLOW HAS GENERALLY SURGED S OF
THE REMNANT MCS ACROSS CNTRL IL...THE LEADING PORTION OF THE MCS HAS
TAKEN ON A MORE N/S-ORIENTATION THAT IS PERPENDICULAR TO THE
DEEP-LAYER WLY FLOW. AS SURFACE HEATING CONTINUES DOWNSTREAM AND
WITH CONVECTIVE TEMPERATURES IN THE 80S BASED ON THE 12Z ILN
RAOB...ONGOING ACTIVITY WILL BECOME SURFACE-BASED. SOME UNCERTAINTY
DOES EXISTS ON WHEN THIS TRANSITION WILL OCCUR. BUT AMIDST FAVORABLE
0-6 KM SPEED SHEAR AS SAMPLED BY THE WOLCOTT IND
PROFILER...CONVECTION WILL INTENSIFY AT SOME POINT AND LIKELY
DEVELOP EMBEDDED SHORT-LINE SEGMENTS CAPABLE OF PRODUCING DAMAGING
WINDS.
..GRAMS/THOMPSON.. 09/07/2012
...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT...
ATTN...WFO...CLE...ILN...IWX...IND...LOT...ILX...LSX...
LAT...LON 41408583 41398416 40538371 39888405 39348492 38888783
39088885 39428904 39948873 40438720 41408583
