MESOSCALE PRECIPITATION DISCUSSION 0459
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
304 AM EDT MON JUL 10 2017

AREAS AFFECTED...FAR SOUTHERN MN...NORTHEAST IA...SOUTHERN
WI...NORTHERN IL...NORTHWEST IN...SOUTHWEST LOWER MI

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

VALID 100700Z - 101230Z

SUMMARY...STRONG MCC WITH INTENSE RAINFALL RATES WILL CONTINUE TO
ADVANCE SOUTHEAST OVER THE NEXT SEVERAL HOURS. SOME FLASH FLOODING
WILL REMAIN POSSIBLE.

DISCUSSION...EXPERIMENTAL GOES-16 10.3 MICRON/IR IMAGERY SHOWS A
CLASSIC LOOKING MCC DRIVING SOUTHEAST ACROSS THE UPPER
MIDWEST...WITH VERY COLD CLOUD TOPS TO ABOUT -75C MOVING DOWN NOW
INTO NORTHEAST IA...AND WITH THE LARGER CONVECTIVE MASS ENVELOPING
AN AREA THAT NOW EXTENDS ACROSS A LARGE AREA OF SOUTHERN WI AND
GETTING INTO PARTS OF NORTHERN IL.

RADAR IMAGERY SHOWS MULTIPLE INTENSE LINE SEGMENTS MOVING
PROGRESSIVELY DOWN THROUGH NORTHEAST IA...WHICH IS NOW
PREDOMINANTLY IN THE WARM SECTOR AND TAKING FULL ADVANTAGE OF A
SOUTHWEST LOW LEVEL JET OF 40 TO 45 KTS WITH ROBUST
MOISTURE/INSTABILITY TRANSPORT HELPING TO SUSTAIN THE CONVECTIVE
ORGANIZATION. MEANWHILE...FARTHER EAST OVER INTO SOUTHERN WI AND
PARTS OF NORTHERN IL...THE STRONG WARM ADVECTION PATTERN AIDED BY
THE LOW LEVEL JET IS ALSO FOCUSING A RATHER INTENSE BAND OF SLOWER
MOVING SHOWERS AND THUNDERSTORMS IN AN ELEVATED FASHION NORTH OF A
QUASI-STATIONARY FRONTAL BOUNDARY. THIS BAND IS PRODUCING RAINFALL
RATES OF UP TO 3 INCHES/HR...AND ALREADY RADAR ESTIMATES OF 3 TO 5
INCHES HAVE BEEN NOTED LOCALLY OVER PARTS OF COLUMBIA...KANE AND
SAUK COUNTIES...INCLUDING THE WEST SIDE OF MADISON.

ADDITIONAL HEAVY RAINS WITH THE MCC WILL CONTINUE THIS MORNING AS
IT MOVES SOUTHEAST THROUGH THE REMAINDER OF NORTHEAST IA AND
SOUTHERN WI...BUT EXPECT LOCALLY SIGNIFICANT IMPACTS OVER AREAS OF
NORTHERN IL TO ARRIVE OVER THE NEXT COUPLE HOURS AND THEN EVEN
INTO NORTHWEST IN AND SOUTHWEST LOWER MI TOWARD DAWN GIVEN THE
FORWARD PROPAGATION OF THE CONVECTIVE MASS.

FLASH FLOODING WILL REMAIN POSSIBLE ACROSS THE MPD THREAT
AREA...ALTHOUGH THE FORWARD PROPAGATION WILL TEND TO MITIGATE THE
OVERALL THREAT. GENERALLY A THREAT FOR 2 TO 4 INCHES EXISTS WITH
THE HEAVIEST AMOUNTS LIKELY TO REMAIN FOCUSED OVER AREAS OF
SOUTHERN WI AND NORTHERN IL ALONG AND NORTH OF THE
QUASI-STATIONARY FRONT. SOME ISOLATED HEAVIER AMOUNTS EXCEEDING 5
INCHES WILL BE POSSIBLE HERE.

ORRISON

ATTN...WFO...ARX...DMX...DVN...GRR...ILX...IWX...LOT...MKX...
MPX...

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

LAT...LON   44299384 43959298 43639180 43829059 43698881
            42958660 42008571 41128607 40758710 40758880
            40999047 41409182 41649251 42299341 43169396
            44019437