MESOSCALE PRECIPITATION DISCUSSION 0571
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
1246 AM EDT TUE AUG 16 2016
 
AREAS AFFECTED......SOUTHERN LOWER MICHIGAN... 
 
CONCERNING...HEAVY RAINFALL...FLASH FLOODING POSSIBLE 
 
VALID 160500Z - 161200Z
 
SUMMARY...AN AREA OF MODERATE TO HEAVY RAIN  IS EXPECTED TO
PERSIST THROUGH THE NEXT SEVERAL HOURS AS IT MOVES NORTHEASTWARD
ACROSS LOWER MICHIGAN. FLASH FLOODING IS POSSIBLE.

DISCUSSION...HIGHLY MOIST AIR WITH PRECIPITABLE WATER VALUES
AROUND 2 INCHES  CONTINUES TO BE TRANSPORTED FROM IN INTO LOWER
MI.  THE STRONG MOISTURE TRANSPORT IS AIDED BY WELL DEFINE 850-700
MB DEFORMATION AND CONVERGENCE...SUPPORTING A LARGE AREA OF
MODERATE TO HEAVY RAIN ACROSS SOUTHERN LOWER MI. 

RAINFALL RATES OF 1-1.5 IN/HR ARE OCCURRING AT THIS TIME IN
HEAVIER ELEVATED CONVECTIVE CELLS EMBEDDED WITHIN THE LARGER RAIN
AREA. UPSTREAM...4 INCHES OF RAIN WAS OBSERVED IN A SEVERAL HOUR
INTERVAL IN SOUTH BEND IN. 

THIS AREA OF MODERATE TO HEAVY RAIN
IS FORECAST TO PERSIST THE REST OF TONIGHT AS THE AREA MOVES
NORTHEAST ACROSS LOWER MI TOWARDS LAKE HURON. THE OPERATIONAL 
HIGH RES RAPID REFRESH, NSSL WRF, AND OPERATIONAL NAM INDICATE A
GENERAL 1 TO 3 INCHES OF RAIN WITH ISOLATED MAXIMA OF 4 INCHES
POSSIBLE. 

STRONG SPEED CONVERGENCE ON THE NOSE OF THE 850-700 MB JET
FORECAST TO BE 40-50 KT SUPPORTS THE RAINFALL AREAS PERSISTING.
LIFT IS AIDED BY UPPER DIVERGENCE MAXIMA IN THE RIGHT ENTRANCE
REGION OF THE UPPER LEVEL JET CROSSING NORTHERN LOWER MI. 

THE FLASH FLOODING THREAT WILL BE SOMEWHAT LIMITED BY MODERATE TO
HIGH FLASH FLOOD GUIDANCE, BUT HIGHER RATES WILL BE CAPABLE OF
PRODUCING ISOLATED FLASH FLOODING. 

PETERSEN

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

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

LAT...LON   44408216 43618188 42948274 42298384 41848486 
            42078586 42918583 43518533 43888476 44308382