844
AWUS01 KWNH 121803
FFGMPD
WVZ000-OHZ000-KYZ000-INZ000-ILZ000-122300-
MESOSCALE PRECIPITATION DISCUSSION 1024
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
201 PM EDT WED AUG 12 2026
AREAS AFFECTED...CENTRAL IL...CENTRAL IN...SOUTHERN OH...EASTERN
KY
CONCERNING...HEAVY RAINFALL...FLASH FLOODING LIKELY
VALID 121800Z - 122300Z
SUMMARY...WIDESPREAD HEAVY RAINFALL IS EXPECTED TO CONTINUE
THROUGH THE MID AFTERNOON HOURS ACROSS AREAS THAT HAVE ALREADY
BEEN HAMMERED BY FLOODING RAINS. MAJOR FLOODING IS LIKELY ACROSS
PORTIONS OF EAST-CENTRAL INDIANA OVER THE NEXT COUPLE OF HOURS
WITH RAINFALL RATES IN EXCESS OF 2 INCHES PER HOUR AT TIMES, AND
MORE SCATTERED INSTANCES OF FLOODING ACROSS SOUTHERN PORTIONS OF
THE OUTLOOK AREA.
DISCUSSION...THE LONG-LIVED, BACK BUILDING MCS THAT WAS INITIALLY
OVER INDIANA AND OHIO HAS NOW MERGED WITH THE MORE PROGRESSIVE MCS
THAT HAS TRACKED ACROSS ILLINOIS. THIS IS LEADING TO CONTINUED
ENHANCED ASCENT WITH NUMEROUS INTENSE THUNDERSTORMS THAT ARE
TRAINING OVER AREAS THAT HAVE ALREADY BEEN INUNDATED WITH EXTREME
RAINFALL, IN SOME CASES APPROACHING 8 INCHES SINCE MIDNIGHT
BETWEEN INDIANAPOLIS AND RICHMOND, INDIANA, BASED ON MULTIPLE
GAUGE MEASUREMENTS. THIS HAS LEAD TO INCREDIBLY LOW FLASH FLOOD
GUIDANCE VALUES, GENERALLY UNDER A QUARTER INCH/3 HR ACROSS THIS
REGION, AND ANY ADDITIONAL RAINFALL WILL ONLY EXACERBATE THE
SERIOUS FLOODING SITUATION THAT IS ONGOING.
THE HEAVIEST RAINFALL RATES ARE LIKELY TO SUBSIDE AFTER 20Z FOR
THE HARDEST HIT AREAS OF CENTRAL INDIANA AND WESTERN OHIO FOLLOWED
BY LIGHTER STRATIFORM RAIN BEHIND THE MAIN CONVECTIVE LINE. THE
MCS SHOULD EVENTUALLY MOVE OVER SOUTHERN INDIANA AND INTO NORTHERN
KENTUCKY LATER THIS AFTERNOON AS THE COMPLEX BECOMES MORE
PROGRESSIVE WITH TIME.
RECENT CAM GUIDANCE HAS GENERALLY BEEN TOO LOW IN MANY CASES WITH
OBSERVED RAINFALL THUS FAR TODAY. LOOKING AHEAD OVER THE NEXT 6
HOURS, THE RRFS IS HEAVIER WITH ITS QPF COMPARED TO THE HRRR, AND
THE FORMER IS THE MORE LIKELY OUTCOME GIVEN ONGOING TRENDS ON
RADAR/SATELLITE. THE RRFS SUGGESTS THE POTENTIAL FOR ADDITIONAL
1-3 INCH RAINFALL ACROSS CENTRAL AND INTO SOUTHERN INDIANA THROUGH
00Z, AND GENERALLY UNDER 2 INCHES ELSEWHERE. FLASH FLOODING IS
LIKELY ACROSS EASTERN INDIANA INTO SOUTHWESTERN OHIO, AND IS
CONSIDERED POSSIBLE FARTHER SOUTH WITHIN THE OUTLOOK AREA.
HAMRICK
..PLEASE SEE WWW.WPC.NCEP.NOAA.GOV FOR GRAPHIC PRODUCT
ATTN...WFO...ILN...ILX...IND...IWX...JKL...LMK...PAH...RLX...
ATTN...RFC...MSR...TIR...NWC...
LAT...LON 41208495 40698397 38978254 37968236 37258282
37058413 37288487 38088614 38688748 39198823
39618831 39938809 40148788 40348697 41028593
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