MESOSCALE PRECIPITATION DISCUSSION 0396
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
458 PM EDT WED JUN 29 2016
 
AREAS AFFECTED...MAINE 
 
CONCERNING...HEAVY RAINFALL...FLASH FLOODING POSSIBLE 
 
VALID 292100Z - 300200Z
 
SUMMARY...LINEAR CONVECTION WITH HOURLY RAINFALL RATES NEAR 1.50
INCHES COULD RESULT IN FLASH FLOODING INTO THE EVENING HOURS.

DISCUSSION...CONVECTION ALONG AND AHEAD OF A COLD FRONT MOVING
SLOWLY EASTWARD THROUGH WESTERN ME CONTINUES TO PRODUCE HEAVY
RAINFALL. THE INDIVIDUAL CELLS IN THE LINE ARE TRAVELING
NORTHEAST...ALONG WITH THE MEAN 850-300 MB WIND (AHEAD OF A SHORT
WAVE IN THE FLOW). THE CONVECTION IS BEING MAINTAINED IN AN
ENVIRONMENT OF 1000 J/KG MLCAPE...AS WELL AS 1.25 TO 1.50 INCH
PRECIPITABLE WATER AIR. 

THE NORTHEAST MOVEMENT OF THE CELLS IS RESULTING IN TRAINING ALONG
THE LINE...AND THE KGYX RADAR HAS INDICATED HOURLY RAINFALL RATES
NEAR 1.50 INCHES ACROSS THE MOUNTAINS OF WESTERN ME. THE HEAVY
RAINFALL IS MOVING INTO AREAS THAT RECEIVED HEAVY RAINFALL
TUE...AND ONE HOUR FLASH FLOOD GUIDANCE VALUES ARE AS LOW AS AN
INCH OVER PORTIONS OF FRANKLIN AND SOMERSET COUNTIES. 

THE LATEST RAP SHOWED THAT THE MOISTURE AND INSTABILITY IN PLACE
SHOULD BE SUFFICIENT TO MAINTAIN THE CONVECTION AS IT CROSSES
CENTRAL ME INTO THE EVENING HOURS. AFTER 00Z...THE INSTABILITY
BEGINS TO BECOME EXHAUSTED FROM NORTH TO SOUTH (PER RAP
SOUNDINGS)...AND THE THREAT IS EXPECTED TO DIMINISH ACROSS EASTERN
ME LATE THIS EVENING. THERE IS FAIRLY GOOD AGREEMENT IN HIGH
RESOLUTION GUIDANCE (INCLUDING THE LATEST HRRR/HRRR
EXPERIMENTAL/12Z WRF-ARW) FOR LOCAL 2-3 INCHES RAINFALL
AMOUNTS...WITH THE HIGHEST AMOUNTS ACROSS THE HIGHER TERRAIN OF
CENTRAL AND NORTHERN ME. 

CONSIDERING THE AMOUNT OF RAINFALL THAT  FELL OVER PORTIONS OF
WESTERN AND NORTHERN ME IN THE LAST 24 TO 30 HOURS...THE
ADDITIONAL RAINFALL COULD RESULT IN FLASH FLOODING.

HAYES

ATTN...WFO...CAR...GYX...

ATTN...RFC...NERFC...

LAT...LON   46886965 46816840 46226801 45796783 45336786 
            44956793 44626810 44426855 43887001 43577056 
            43517093 43607094 44187059 44677031 45347021 
            45937033 46387044