AREAS AFFECTED...IL
CONCERNING...SEVERE POTENTIAL...WATCH LIKELY
VALID 011741Z - 011845Z
PROBABILITY OF WATCH ISSUANCE...95 PERCENT
SUMMARY...AFTERNOON HEATING WILL CONTRIBUTE TO FURTHER
DESTABILIZATION ACROSS IL YIELDING AN INCREASING THREAT FOR ISOLATED
TORNADOES AND PERHAPS LOCALLY DAMAGING WINDS.
DISCUSSION...REMNANTS OF TROPICAL SYSTEM ISAAC ARE DRIFTING SLOWLY
EWD ACROSS MO EARLY THIS AFTERNOON. DOWNSTREAM...PARTIAL BREAKS IN
CLOUD COVER HAVE CONTRIBUTED TO STEEPENING LOW LEVEL LAPSE RATES
WITHIN THE BOUNDARY LAYER ACROSS IL. THIS APPEARS TO BE MOSTLY
RESPONSIBLE FOR INCREASE IN SMALL DISCRETE SHOWERS THAT HAVE
DEVELOPED ACROSS MUCH OF CNTRL IL WITHIN FAVORABLY MOIST BUT
MARGINALLY SHEARED ENVIRONMENT. SEVERAL REPORTS OF TORNADOES HAVE
BEEN NOTED WITH THESE SMALL SHOWERS AND ADDITIONAL SHORT-LIVED WEAK
TORNADOES COULD OCCUR.
ADDITIONALLY...A NARROW LINE OF CONVECTION IS GRADUALLY INCREASING
IN INTENSITY ACROSS WCNTRL IL AND THIS APPEARS LOOSELY CORRELATED
WITH A MID LEVEL DRY INTRUSION AND POSSIBLE MID LEVEL VORT LOBE.
ALTHOUGH LIGHTNING HAS YET TO BE NOTED WITH THIS ACTIVITY ADDITIONAL
HEATING SHOULD CONTRIBUTE TO MORE INTENSE UPDRAFTS. LOCALLY
DAMAGING WINDS MAY ULTIMATELY EVOLVE WITH THIS SQUALL LINE ALONG
WITH THE POSSIBILITY FOR ISOLATED TORNADOES.
..DARROW/CORFIDI.. 09/01/2012
...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT...
ATTN...WFO...PAH...LOT...ILX...LSX...DVN...
LAT...LON 41178890 41169004 40459066 39709026 38948985 37618961
37918817 40188786 41178890
