MESOSCALE PRECIPITATION DISCUSSION 0653
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
744 PM EDT WED SEP 07 2016
 
AREAS AFFECTED...CENTRAL/NORTHERN LOWER MICHIGAN 
 
CONCERNING...HEAVY RAINFALL...FLASH FLOODING POSSIBLE 
 
VALID 072343Z - 080400Z
 
SUMMARY...ADDITIONAL SHOWERS AND THUNDERSTORMS ARE EXPECTED TO
MOVE ACROSS CENTRAL/NORTHERN LOWER MICHIGAN OVER THE NEXT SEVERAL
HOURS. THESE STORMS COULD PRODUCE AN ADDITIONAL 2 TO 3 INCHES OF
RAINFALL OVER AREAS THAT HAVE ALREADY RECEIVED 1 TO 2 INCHES.
THESE ADDITIONAL HEAVY RAINS FALLING ON SATURATED GROUND COULD
LEAD TO ISOLATED AREAS OF FLASH FLOODING.

DISCUSSION...A STATIONARY FRONTAL BOUNDARY IS SITUATED ACROSS
CENTRAL LOWER MICHIGAN, WITH A VERY WARM AND MOIST (PWATS > 2.00
INCHES) AIR MASS IN PLACE SOUTH OF THE BOUNDARY. SOUTHWESTERLY 850
HPA WINDS OF 30-40 KT ARE TRANSPORTING THIS UNSTABLE (MUCAPE OF
1000-2000 J/KG) ACROSS THE FRONT RESULTING IN NUMEROUS SHOWERS AND
THUNDERSTORMS. ADDITIONALLY, A LINE OF SHOWERS AND THUNDERSTORMS
IS CROSSING LAKE MICHIGAN AND WILL MOVE ONSHORE IN CENTRAL
MICHIGAN OVER THE NEXT COUPLE HOURS. RADAR ESTIMATES INDICATE
RAINFALL RATES OF 1-2 IN/HR IN THIS LINE OF CONVECTION ACROSS LAKE
MICHIGAN. VERY LITTLE IN THE WAY OF CLOUD TOP WARMING EVIDENT ON
IR SATELLITE IMAGERY INDICATE THAT THIS CONVECTION SHOULD MAINTAIN
CLOSE TO ITS CURRENT INTENSITY AS IT MOVES INTO MICHIGAN.

SEVERAL HI-RES MODELS, INCLUDING THE HRRR, HRRR-EXPERIMENTAL,
NSSL-WRF, AND THE NAM-CONEST SHOW GOOD AGREEMENT ON A BAND OF 2-3
INCH RAINFALL (LOCALLY HIGHER) AMOUNTS ACROSS CENTRAL/NORTHERN
LOWER MICHIGAN THROUGH 04Z. FLASH FLOOD GUIDANCE VARIES WIDELY
OVER THIS AREA, WITH AREAS THAT RECEIVED EARLIER RAINS THE MOST
LIKELY TO EXCEED FFG. THUS, ISOLATED FLASH FLOODING IS POSSIBLE.

RYAN

ATTN...WFO...APX...DTX...GRR...

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

LAT...LON   44868394 44748338 44398321 44048336 43658381 
            43298459 43068541 43178623 43608674 44108642 
            44418580 44748477 
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