MESOSCALE PRECIPITATION DISCUSSION 0169
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
117 AM EDT SUN APR 30 2017

AREAS AFFECTED...NORTHWEST AR..SOUTHERN MO...SOUTHERN
IL....SOUTHERN IN...FAR NORTHWEST KY

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

VALID 300510Z - 301000Z

SUMMARY...ADDITIONAL HEAVY RAINS ARE EXPECTED THROUGH THE
REMAINDER OF THE NIGHT WITH SOME ADDITIONAL FLASH FLOODING
EXPECTED.

DISCUSSION...EXPERIMENTAL GOES-16 10.3 MICRON/IR IMAGERY
OVERWHELMING SHOWS THE MOST VIGOROUS CONVECTIVE ACTIVITY OCCURRING
OVER A LARGE AREA OF CENTRAL AND NORTHEAST AR WITH EXTREMELY COLD
CONVECTIVE TOPS NOTED. MEANWHILE...FARTHER NORTH AND TO THE NORTH
OF A WELL-DEFINED OUTFLOW BOUNDARY...THERE CONTINUES TO BE A LARGE
AREA OF MODERATE TO HEAVY RAIN WITH SOME EMBEDDED STRONGER
CONVECTIVE CLUSTERS THAT EXTEND FROM NORTHWEST AR/SOUTHWEST MO
EASTWARD ACROSS SOUTHERN MO AND UP ALONG THE LOWER OH RIVER VALLEY.

OVER THE NEXT FEW HOURS...THE STRONG LOW LEVEL JET AND ASSOCIATED
MOISTURE FLUX COUPLED WITH INSTABILITY TRANSPORT WILL CONTINUE TO
FOCUS AREAS OF HEAVY SHOWERS AND THUNDERSTORMS ACROSS THE THREAT
AREA...AND ESPECIALLY ACROSS SOUTHERN MO. FARTHER EAST ACROSS
SOUTHERN IL AND SOUTHERN IN...THE 00Z ARW/NMMB SOLUTIONS AND
RECENT HRRR GUIDANCE SUPPORT A GENERAL DOWNTICK IN CONVECTIVE
ORGANIZATION AS THE STRONGER SYNOPTIC FORCING TENDS TO FOCUS MORE
ON AR/MO...HOWEVER...THE LOW LEVEL JET WILL TEND TO BE OVERRUNNING
THE OUTLFOW BOUNDARY AND SURFACE COLD POOL THAT EXISTS AS FAR EAST
AS SOUTHERN IL AND SOUTHERN IN. OVER THESE AREAS...SOME OCCASIONAL
CLUSTERS OF CONVECTION MAY TEND TO REDEVELOP AS A RESULT.

GIVEN THE SATURATED SOIL CONDITIONS...AND ADDITIONAL HEAVY RAIN IS
LIKELY TO RESULT IN MORE FLASH FLOODING. THE GREATEST THREAT WILL
BE OVER SOUTHERN MO FOR THIS TO HAPPEN WHERE CONFIDENCE IS
GREATEST WITH ADDITIONAL HEAVY RAINS OVERNIGHT. EXPECT LOCALLY AN
ADDITIONAL 1 TO 2 INCHES OF RAIN TO BE POSSIBLE...WITH ISOLATED
HEAVIER AMOUNTS THROUGH THE END OF THE NIGHT.

ORRISON

ATTN...WFO...ILN...ILX...IND...LMK...LSX...LZK...MEG...PAH...
SGF...TSA...

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

LAT...LON   39558604 39328474 38578483 37898615 37408726
            37118812 36808925 36539091 36399139 35959249
            35319321 34549387 34719410 35289385 35749399
            36169417 36519455 36859442 37149379 37329271
            37649123 38019022 38298964 38778895 39208789