MESOSCALE PRECIPITATION DISCUSSION 0298
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
1019 PM EDT TUE JUN 12 2018

AREAS AFFECTED...SE INDIANA...SRN OHIO...FAR NRN KENTUCKY

CONCERNING...HEAVY RAINFALL...FLASH FLOODING LIKELY

VALID 130216Z - 130800Z

SUMMARY...THUNDERSTORMS WERE DEVELOPING IN A WEST-EAST AXIS FROM
SOUTHERN INDIANA INTO SOUTHERN OHIO AS OF 10 PM EDT. THESE STORMS
MAY BEGIN TO REPEATEDLY AFFECT THE SAME AREAS AND PRODUCE HEAVY
RAINFALL. RAIN RATES TO AROUND 2 IN/HR AND LOCALIZED TOTALS IN
EXCESS OF 3 INCHES WILL BE POSSIBLE.

DISCUSSION...REGIONAL RADARS AND GOES-16 IR SATELLITE IMAGERY SHOW
A BAND OF CONVECTION DEVELOPING AS OF 02Z FROM ROUGHLY BMG TO CVG
TO RZT. THE CONVECTION WAS ORIENTED NEARLY PARALLEL TO THE
OBSERVED STORM MOTIONS (EASTERLY) WHICH SHOULD ENABLE TRAINING OF
THUNDERSTORMS OVER THE NEXT SEVERAL HOURS. THIS ACTIVITY IS LIKELY
TO BECOME FOCUSED ALONG THE NOSE OF AN INCREASING LOW-LEVEL JET.
INSTABILITY ACROSS THE REGION IS RELATIVELY WEAK WITH MUCAPE
VALUES ONLY AROUND 200-800 J/KG OVER MUCH OF THE OUTLINED AREA.
HOWEVER...THIS SHOULD BE COMPENSATED BY DEEP MOISTURE. THE 00Z ILN
SOUNDING SHOWED PRECIPITABLE WATER VALUE OF AROUND 1.8 INCHES AND
THIS WAS SUPPORTED BY NEARBY GPS-PW OBSERVATIONS. THESE VALUES ARE
EASILY ABOVE THE 90TH PERCENTILE FOR JUNE IN THIS REGION...AND
NEAR THE DAILY RECORD LEVEL FOR THE ILN SOUNDING CLIMATOLOGY. WITH
THE DEEP MOISTURE AND MOST OF THE POSITIVELY BUOYANT REGION ON THE
SOUNDINGS BELOW THE MELTING LAYER...STORMS ARE GENERALLY EXPECTED
TO BE EFFICIENT RAINFALL PRODUCERS.

GIVEN THE POTENTIAL FOR TRAINING AND THE OVERALL
ENVIRONMENT...RAIN RATES OF 2+ IN/HR SEEM ACHIEVABLE WHERE
STRONGER CONVECTION MANAGES TO TRAIN OR PERSIST FOR SUFFICIENT
DURATION. THIS MAY ALSO LEAD TO SMALL SWATHS OF RAIN TOTALS IN
EXCESS OF 3 OR 4 INCHES...AND FLASH FLOODING. 3-HR FFG ACROSS THE
AREA IS MOSTLY IN THE 1.5 TO 2.0 INCH RANGE...WHICH SHOULD BE
EASILY REACHED IN THE STRONGER TRAINING CONVECTION.
THEREFORE...FLASH FLOODING APPEARS LIKELY IN AT LEAST SOME
PORTIONS OF THE OUTLINED AREA...AND THE AREA OF GREATEST CONCERN
WOULD BE FROM SOUTHEAST INDIANA INTO THE CINCINNATI METRO AREA
WHERE ONGOING STORMS HAVE ALREADY BEEN OBSERVED...AND IS FURTHER
WEST TOWARD GREATER INSTABILITY.

LAMERS

ATTN...WFO...ILN...IND...LMK...PBZ...RLX...

ATTN...RFC...OHRFC...

LAT...LON   40088207 39898125 39308135 38878295 38658463
            38758648 39398640 39808453