MESOSCALE PRECIPITATION DISCUSSION 0416
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
539 AM EDT FRI JUN 30 2017

AREAS AFFECTED...WESTERN FL PANHANDLE AND NEARBY SOUTHERN AL

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

VALID 300945Z - 301300Z

SUMMARY...SLOW MOVING CELLS IN A HIGH MOISTURE CONTENT AIRMASS
COULD RESULT IN A LOCALIZED FLASH FLOOD THREAT THIS MORNING.

DISCUSSION...SCATTERED CONVECTION CONTINUES TO FORM IN A TROPICAL
AIRMASS (WITH PRECIPITABLE WATER VALUES NEAR 2.30 INCHES...PER THE
MOST RECENT BLENDED TPW PRODUCT). THE CONVECTION THUS FAR HAS BEEN
LIMITED TO THE THE WESTERN FL PANHANDLE... WHERE MUCAPE VALUES
HOVER BETWEEN 500 AND 1000 J/KG. THE LIMITED SPATIAL EXTENT OF THE
MUCAPE HAS KEPT THE CONVECTION SCATTERED AHEAD OF A MID LEVEL LOW
LIFTING SLOWLY OUT OF SOUTHERN MS.

THE KMOB RADAR HAS INDICATED HOURLY RAINFALL RATES BETWEEN 2.00
AND 2.50 INCHES WITH THE SCATTERED CONVECTION OVER THE WESTERN FL
PANHANDLE...AND GIVEN THE DEPTH OF THE TROPICAL MOISTURE...THESE
AMOUNTS SEEM REASONABLE. THE STORM MOTION HAS BEEN SLOWLY
NORTHEAST...AS THE 850-300 MB FLOW IS FAIRLY WEAK AHEAD OF THE
SHORT WAVE.

THE LATEST HRRR SUGGESTS THAT THE BEST CONVECTION SHOULD REMAIN
LIMITED TO THE WESTERN FL PANHANDLE AND NEARBY SOUTHERN
AL...CLOSEST TO THE BEST INSTABILITY. THE INSTABILITY DOES NOT
APPEAR TO EXTEND MUCH FURTHER NORTH THROUGH ABOUT 13Z...SO THE
MAIN FLASH FLOOD THREAT SHOULD REMAIN IN THIS AREA.

THE LATEST HRRR ALSO INDICATED LOCAL 2.00 TO 4.00 INCH RAINFALL
AMOUNTS OVER PORTIONS OF THE WESTERN FL PANHANDLE AND NEARBY
SOUTHERN AL...MUCH OF WHICH COULD FALL IN BETWEEN ONE AND TWO
HOURS. WHILE FLASH FLOOD GUIDANCE VALUES ARE FAIRLY HIGH...THE
HIGHER RAINFALL AMOUNTS COULD APPROACH THOSE VALUES...AND FLASH
FLOODING IS CONSIDERED POSSIBLE THROUGH ABOUT 13Z.

HAYES

ATTN...WFO...BMX...MOB...TAE...

ATTN...RFC...SERFC...

LAT...LON   31788564 31388523 30668536 30268594 30398708
            30858706 31498659