MESOSCALE PRECIPITATION DISCUSSION 0345
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
1231 PM EDT THU JUN 21 2018

AREAS AFFECTED...NORTHEAST IL...CENTRAL IN...SOUTHERN
OH...NORTHERN KY

CONCERNING...HEAVY RAINFALL...FLASH FLOODING POSSIBLE

VALID 211630Z - 212230Z

SUMMARY...HEAVY SHOWERS AND STRONG THUNDERSTORMS OVER THE NEXT FEW
HOURS WITH ENHANCED RAINFALL RATES TO NEAR 2 INCHES PER HOUR WILL
RESULT IN SOME FLASH FLOODING CONCERNS THIS AFTERNOON.

DISCUSSION...THE LATEST RADAR IMAGERY SHOWS A RELATIVELY
CONCENTRATED AXIS OF HEAVY SHOWERS AND EMBEDDED THUNDERSTORMS
MOVING ACROSS THE GREATER CHICAGO AREA AND INTO NORTH-CENTRAL
INDIANA EARLY THIS AFTERNOON.  THIS IS IN ASSOCIATION WITH A SLOW
MOVING FRONTAL BOUNDARY AHEAD OF A CLOSED MID LEVEL LOW NEAR THE
MISSISSIPPI RIVER.  ANOMALOUS PWS ON THE ORDER OF 2 INCHES PER THE
LATEST RAP ANALYSIS IS POOLING IN THE VICINITY OF THE WARM FRONT,
AND A DEEP WARM CLOUD LAYER IS AIDING IN THE PRECIPITATION
EFFICIENCY DESPITE ONLY MODEST CAPE VALUES.  RAINFALL RATES MAY
APPROACH 1.5 TO 2.5 INCHES PER HOUR WITHIN THE MOST PERSISTENT
CONVECTIVE BANDS GIVEN THE SLOW MOVEMENT OF THE MAIN RAINFALL AXIS.

THE LATEST HRRR, HRRRX, WRF, AND ARW HIGH RES GUIDANCE SUPPORTS AN
AXIS OF SCATTERED 1 TO 3 INCH AMOUNTS THROUGH 19Z, WITH LOCALIZED
HIGHER AMOUNTS, THAT IS ROUGHLY ALONG AND TO THE EAST OF THE
INTERSTATE 65 CORRIDOR.  FLASH FLOODING IS POSSIBLE DURING PERIODS
OF INTENSE RAINFALL, ESPECIALLY ACROSS AREAS THAT HAVE RECEIVED
APPRECIABLE RAIN OVER THE PAST 24 HOURS.

D. HAMRICK

ATTN...WFO...GRR...ILN...ILX...IND...IWX...JKL...LMK...LOT...
MKX...RLX...

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

LAT...LON   42538793 42468683 41998592 41298489 40358408
            39028291 38318314 38018372 38048462 38368538
            39348663 40178752 41098854 41698879 42258854