MESOSCALE PRECIPITATION DISCUSSION 0142
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
754 PM EDT WED MAY 27 2015
 
AREAS AFFECTED......NORTHERN AND CENTRAL AL/SOUTH CENTRAL TN... 
 
CONCERNING...HEAVY RAINFALL...FLASH FLOODING POSSIBLE 
 
VALID 272353Z - 280233Z
 
SUMMARY..MERGING CONVECTION IN A HIGH MOISTURE CONTENT AIRMASS
COULD RESULT IN FLASH FLOODING THROUGH THE LATE EVENING.

DISCUSSION...KBMX RADAR SHOWED CONVECTION WITH IR CLOUD TOP
TEMPERATURES NEAR -70 C ACROSS NORTHERN AL...WITH HOURLY RATES
NEAR 2 INCHES (BASED ON RADAR ESTIMATES). A LINE OF CONVECTION
MOVING NORTHEAST FROM CENTRAL AL WILL MERGE WITH THE COLD TOP
CONVECTION ACROSS NORTHERN AL AND SOUTH CENTRAL TN DURING THE
EVENING HOURS.  

THE MERGER COULD RESULT IN FLASH FLOODING ACROSS THESE AREAS...AS
PRECIPITABLE WATER VALUES REMAIN NEAR 1.75 INCHES. INFLOW AHEAD OF
THE LINE OF CONVECTION APPROACHING FROM CENTRAL AL IS
WEAKENING...BUT CELL MERGERS INCREASE THE FLASH FLOOD THREAT. THE
LATEST HRRR SHOWED LOCAL 2-3 INCH RAINFALL AMOUNTS THROUGH 0200Z
ACROSS NORTHERN AL...BEFORE THE ACTIVITY SLOWLY WEAKENS AS
INSTABILITY STARTS TO WANE. RAINFALL AMOUNTS THIS HIGH COULD
RESULT IN FLASH FLOODING.

HAYES

ATTN...WFO...BMX...FFC...HUN...MRX...OHX...

ATTN...RFC...LMRFC...OHRFC...SERFC...

LAT...LON   35908629 35618580 35218568 35178554 35068553 
            33868534 32878562 32348621 32518757 33078814 
            33608824 33578825 33968811 35518738