Graphic for MPD #0173

MESOSCALE PRECIPITATION DISCUSSION 0173
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
1115 AM EDT SUN APR 30 2017

AREAS AFFECTED...EASTERN MO...SOUTHERN/CENTRAL IL...WEST-CENTRAL
IN

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

VALID 301511Z - 301900Z

SUMMARY...ADDITIONAL MODERATE TO HEAVY RAIN WILL FALL OVER
SATURATED SOILS ACROSS PORTIONS OF THE MIDWEST DURING THE NEXT FEW
HOURS...WHICH COULD LEAD TO MORE FLASH FLOODING.

DISCUSSION...BANDS OF THUNDERSTORMS ASSOCIATED WITH A STRONG
FRONTAL SYSTEM MOVING ACROSS THE MIDDLE MISSISSIPPI VALLEY INTO
THE WESTERN OHIO VALLEY SHOULD PRODUCE HOURLY RAIN RATES LOCALLY
EXCEEDING 1"...WITH ANOTHER 1-2.5" OF RAIN DURING THE NEXT FEW
HOURS. THIS MODERATE TO HEAVY RAIN WILL FALL OVER AREAS OF
SATURATED SOILS EXTENDING EAST-NORTHEAST FROM WESTERN MO INTO
WEST-CENTRAL IN...WHERE 3-HOUR FFG VALUES ARE MAINLY LESS THAN
1-1.5". 

CONVERGENT LOW LEVEL FLOW WITH WIND SPEEDS AROUND 45 KT AT 850 MB
WILL CONTINUE FOR SEVERAL HOURS...TRANSPORTING A VERY MOIST AIR
MASS INTO A STATIONARY FRONT ACROSS THE REGION. PRECIPITABLE WATER
REMAINS IN THE RANGE OF 1.75-2". RADAR AND SATELLITE IMAGERY SHOW
MORE CONVECTIVE DEVELOPMENT OVER THE MISSISSIPPI VALLEY BETWEEN
AR/TN WHICH SHOULD MOVE INTO THE REGION OF CONCERN. SPC MESOSCALE
ANALYSES SHOW MUCAPE OF 500-2000 J/KG ACROSS THE AREA...AND THOUGH
DECREASING SLIGHTLY...IT SHOULD REMAIN SUFFICIENT TO SUSTAIN AREAS
OF MODERATE TO HEAVY RAIN. IN ADDITION...UPPER LEVEL DIFFLUENCE IS
FORECAST TO INCREASE A BIT AS THE UPPER LEVEL TROUGH AND ITS JET
APPROACH FROM THE CENTRAL TO SOUTHERN PLAINS.

THE RAP AND HRRR MODELS INDICATE THAT ANOTHER 1-2.5" RAIN WILL
FALL LOCALLY THROUGH 19Z. GIVEN THE HIGH SOIL SATURATION...RECENT
RAINS...AND LOW FFG VALUES...ADDITIONAL FLASH FLOODING IS POSSIBLE.

MCDONNAL

ATTN...WFO...ILX...IND...IWX...LMK...LOT...LSX...PAH...

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

LAT...LON   40698728 40498597 40018545 38758639 37698729
            36928828 36678933 37009016 37799082 38539108
            39279133 39589098 39719076 40238911


Last Updated: 1115 AM EDT SUN APR 30 2017