459
AWUS01 KWNH 120422
FFGMPD
OHZ000-KYZ000-INZ000-120951-
MESOSCALE PRECIPITATION DISCUSSION 1018
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
1222 AM EDT WED AUG 12 2026
AREAS AFFECTED...IN AND NEAR PORTIONS OF IN & SOUTHWEST OH
CONCERNING...HEAVY RAINFALL...FLASH FLOODING POSSIBLE
VALID 120421Z - 120951Z
SUMMARY...THUNDERSTORMS WITH HEAVY RAINFALL HAVE REDEVELOPED
ACROSS SOUTHEAST IN. HOURLY RAIN AMOUNTS TO 2.5" WITH LOCAL
TOTALS TO 4" COULD LEAD TO WIDELY SCATTERED FLASH FLOODING.
DISCUSSION...SHOWERS AND THUNDERSTORMS ARE REDEVELOPING ACROSS
PORTIONS OF IN, WITH ACTIVITY IN SOUTHEAST IN STARTING TO GROW IN
SCALE AS THEY DROP 1.5"+ IN AN HOUR. PRECIPITABLE WATER VALUES
ARE ~1.7" EFFECTIVE BULK SHEAR IS ~30 KTS. AN AREA OF 4000+ J/KG
OF MU CAPE IS MOVING EAST INTO WEST-CENTRAL IN.
THE GUIDANCE SHOWS THE BEST 850 HPA CONFLUENCE SHIFTING FROM NORTH
TO SOUTH ACROSS THE MPD AREA WHILE THE INSTABILITY GRADIENT SHIFTS
EAST WITH TIME ACROSS IN INTO WESTERN OH. THE MESOSCALE GUIDANCE
IS NOT SOLD ON THIS AREA BEING PROBLEMATIC FOR HOURS, HOWEVER.
THE BIG QUESTION MARK IS HOW FAR EAST THE INSTABILITY FIELD IS
GOING TO BE ABLE TO PROGRESS, WHICH DEPENDS UPON UPSCALE GROWTH.
THE FASTER UPSCALE GROWTH OCCURS, THE LESS EASTWARD PROGRESS
CONVECTION MAKE MAKE ACROSS THE MPD AREA. GIVEN THE AVAILABLE
INGREDIENTS, HOURLY RAIN AMOUNTS TO 2.5" WITH LOCAL TOTALS TO 4"
ARE POSSIBLE. THIS WOULD EXCEED THE THREE HOURLY FLASH FLOOD
GUIDANCE VALUES REGIONALLY. BECAUSE OF QUESTIONS CONCERNING THE
SIZE OF THE HEAVY RAIN SIGNAL AND ITS EASTWARD
PROGRESSION/REDEVELOPMENT OVERNIGHT, CHOSE THE FLASH FLOOD
POSSIBLE TAG. WHEREVER HEAVY RAIN FALLS, FLASH FLOODING WOULD BE
POSSIBLE OVER AREAS WITH PARTIALLY IF NOT COMPLETELY SATURATED
SOILS. FLASH FLOOD OCCURRENCES COULD BE WIDELY SCATTERED.
ROTH
..PLEASE SEE WWW.WPC.NCEP.NOAA.GOV FOR GRAPHIC PRODUCT
ATTN...WFO...ILN...IND...IWX...
ATTN...RFC...TIR...NWC...
LAT...LON 41108662 40888526 39268390 38638453 39768615
40478668
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