MESOSCALE PRECIPITATION DISCUSSION 0380
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
1044 AM EDT FRI JUN 23 2017

AREAS AFFECTED...EXTREME SOUTHEAST MO...NORTHWEST KY...SOUTHERN
IL...CENTRAL/SOUTHERN IN...CENTRAL/SOUTHERN OH

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

VALID 231440Z - 232015Z

SUMMARY...HEAVY RAINFALL SHOULD TEND TO BECOME MORE WIDESPREAD AND
CONCENTRATED ALONG AND NORTH OF THE OH RIVER. SOME FLASH FLOODING
WILL BE LIKELY.

DISCUSSION...EXPERIMENTAL GOES-16 6.9 MICRON/WV IMAGERY SHOWS A
SHORTWAVE TROUGH QUICKLY ADVANCING EAST ACROSS CENTRAL/SOUTHERN IL
AND SOUTHEAST MO WHICH IS HELPING TO ENHANCE THE LARGER SCALE
ASCENT DOWNWIND ACROSS MUCH OF THE OH RIVER VALLEY AND IN
CONJUNCTION WITH A WELL-DEFINED LARGE SCALE WARM ADVECTION PATTERN
AHEAD OF A COLD FRONT CROSSING THE MIDWEST. MEANWHILE...A VERY
LARGE POOL OF HIGH PWATS IS IN PLACE WHICH IS BEING FACILITATED BY
THE ADVANCE OF T.D. CINDY WHICH IS ADVANCING OUT OF EASTERN AR AND
INTO WESTERN TN AT THIS TIME. ALREADY THERE IS AN EXPANDING AREA
OF HEAVY SHOWERS AND THUNDERSTORMS NORTH OF THE OH RIVER FROM
SOUTHERN IL EAST ACROS CENTRAL/SOUTHERN IN AND INTO
CENTRAL/WESTERN OH.

CONVECTION SHOULD BECOME EVEN MORE CONCENTRATED OVER THE NEXT FEW
HOURS WITH A TENDENCY TO ALIGN ITSELF FARTHER SOUTHEAST WITH TIME
AND CLOSER TO THE OH RIVER GOING THROUGH ABOUT 18Z. AFTER
18Z...THE CONVECTION SHOULD BEGIN FOCUSING FARTHER SOUTH THAT
AREAS OF WESTERN AND NORTHERN KY BEGIN TO SEE THE HEAVY RAINFALL
THREAT INCREASE. THE ACTIVITY WILL BE ENHANCED BY AN INCREASINGLY
CONVERGENT LOW TO MID LEVEL FLOW PATTERN ALONG AND AHEAD OF THE
COLD FRONT ALONG WITH SUPPORT FROM DEVELOPING RIGHT-ENTRANCE
REGION UPPER JET DYNAMICS. THIS WILL COINCIDE ALSO WITH A MODESTLY
UNSTABLE BOUNDARY LAYER...BUT A VERY MOIST VERTICAL COLUMN WITH
PWATS OF 2 TO 2.5 INCHES. RAINFALL RATES ARE EXPECTED TO APPROACH
3 INCHES/HR WITHIN THE STRONGER CONVECTIVE CORES GIVEN THE HIGHLY
EFFICIENT ENVIRONMENT.

THE HIRES MODELS SHOW A STRONG SIGNAL FOR VERY HEAVY RAINFALL
THROUGH THE REMAINDER OF THE MORNING AND EXTENDING THROUGH THE
MID-AFTERNOON HOURS...WITH TOTALS OF 3 TO 5 INCHES AND ISOLATED
HEAVIER AMOUNTS UP TO 6+ INCHES WHERE SOME LOCALIZED TRAINING OF
CELLS OCCURS. SOME FLASH FLOODING WILL BE LIKELY AS A RESULT.

ORRISON

ATTN...WFO...CLE...ILN...ILX...IND...IWX...LMK...LSX...PAH...
PBZ...RLX...

ATTN...RFC...LMRFC...NCRFC...OHRFC...

LAT...LON   40638283 40568143 40078073 39318118 39058200
            38878295 38588467 38318550 37838639 37048750
            36628883 36668973 37099011 37479014 38358964
            39188884 39968740 40398533