MESOSCALE PRECIPITATION DISCUSSION 0084...CORRECTED
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
1022 AM EDT TUE APR 03 2018

CORRECTED FOR CHANGE HEADER TO FLASH FLOODING LIKELY

AREAS AFFECTED...ERN IL...CNTRL IN INTO OH

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

VALID 031412Z - 031900Z

SUMMARY...PERIODS OF TRAINING RAINFALL ARE LIKELY TO CONTINUE FOR
ANOTHER FEW HOURS WITH HOURLY RAINFALL RATES OF 0.5 TO 1.5 IN/HR
ALLOWING FOR THE POTENTIAL OF ANOTHER 2-4 INCHES LOCALLY THROUGH
20Z FROM ERN ILLINOIS INTO OHIO.

DISCUSSION...ONGOING ELEVATED CONVECTION WAS ORIENTED FROM WEST TO
EAST FROM E-CNTRL ILLINOIS INTO W-CNTRL OHIO AS OF 14Z...OCCURRING
NORTH OF A SLOW MOVING WARM FRONT AT THE NOSE OF A 50-60 KT LOW
LEVEL JET POINTING NORTHEASTWARD ACROSS THE MID-MISSISSIPPI
VALLEY. 12Z RAOBS AND RAP ANALYSES INDICATED THE GREATEST ELEVATED
INSTABILITY ACROSS THE REGION...500-1000+ J/KG WAS LOCATED OVER
CNTRL ILLINOIS INTO WRN INDIANA...WITH VALUES DROPPING OFF RAPIDLY
TOWARD THE EAST INTO OHIO. UPPER AIR DATA ALSO INDICATED A COUPLED
UPPER LEVEL JET SIGNATURE AND ENHANCED DIVERGENCE OVER THE OHIO
VALLEY WITH THE LEFT EXIT REGION OF A 110-120 KT JET CORE ALONG
THE KENTUCKY/TENNESSEE BORDER AND THE RIGHT ENTRANCE REGION OF AN
ENHANCED SPEED MAX OVER ILLINOIS/OHIO.

SHORT TERM FORECASTS FROM THE RAP SHOW THE WARM FRONT LIFTING
NORTH THROUGH 18Z...ALONG WITH MUCAPE EXPANDING NORTH AND EAST.
850 MB FLOW IS EXPECTED TO REMAIN RATHER STRONG INTO THE EARLY
AFTERNOON...AHEAD OF AN APPROACHING UPPER TROUGH AND RELATED
SURFACE COLD FRONT APPROACHING THE MISSISSIPPI VALLEY. UPPER LEVEL
JET PLACEMENT IS EXPECTED TO REMAIN SUPPORTIVE OF UPPER LEVEL
DIVERGENCE AND DIFFLUENCE OVER THE OHIO VALLEY INTO THE AFTERNOON
AS WELL.

THE RESULT IS EXPECTED TO BE CONTINUED TRAINING FROM WEST TO
EAST...WITH THE AXIS OF HEAVY RAIN SLOWLY LIFTING NORTH INTO THE
EARLY AFTERNOON AND A CONTINUED ORIGIN NEAR THE NOSE OF THE LOW
LEVEL JET FROM ERN ILLINOIS INTO CNTRL INDIANA. WHILE NOT EXPECTED
TO BE WIDESPREAD...AN ADDITIONAL 2-4 INCHES WILL BE POSSIBLE ON A
LOCALIZED BASIS THROUGH 20Z WITH CONTINUED FLASH FLOODING.

OTTO

ATTN...WFO...CLE...ILN...ILX...IND...IWX...LOT...LSX...PBZ...
RLX...

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

LAT...LON   40848677 40838465 40658315 40458257 40178207
            39868172 39418169 38998249 38908298 39018458
            39078575 39058677 39078744 39108804 39078908
            39258936 39798928 40208898 40658825