MESOSCALE PRECIPITATION DISCUSSION 0356
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
618 PM EDT WED JUN 21 2017

AREAS AFFECTED...SOUTHEASTERN MS...SOUTHERN AL...WESTERN FL
PANHANDLE

CONCERNING...HEAVY RAINFALL...FLASH FLOODING LIKELY

VALID 212220Z - 220230Z

SUMMARY...ANOTHER BOUT OF HEAVY RAIN MOVING THROUGH COASTAL AREAS
ALREADY EXPERIENCING FLOODING CONDITIONS.

DISCUSSION...GOES-16 CONUS WV LOOP SHOWS DRY SLOT COVERING CENTRAL
GULF/SE LA ATTM WITH DEEP WARM CONVEYOR BELT FURTHER EAST
CURRENTLY DENOTED BY SCATTERED ACTIVE CONVECTION MOVING DUE NORTH.
 INSTABILITY REMAINS FAIRLY HIGH GIVEN MOIST LAPSE RATES WITH
AVAILABLE 1500 J/KG MAINLY OFFSHORE...FALLING TO NEAR ZERO FURTHER
ASHORE WHERE NEARLY PERMANENT CLOUDY SKIES HAS STABILIZED THE
LOWER LEVEL ENVIRONMENT...AS SUCH CONVECTION WILL CONTINUE TO
STRUGGLE REACHING CENTRAL MS/AL AS WEAKENING STRATIFORM.
ADDITIONALLY GIVEN THE CYCLONE'S STRUCTURE...LOW LEVEL SHEARING IS
QUITE STRONG FURTHER FROM THE COAST AND BEST LOW LEVEL CONFLUENCE
LEADING TO TILTED CONVECTION WHICH SUBSTANTIALLY REDUCES EFFECTIVE
RAINFALL GENERATION.  OVER THE OCEAN AND NEAR COASTAL COUNTIES
SHOULD REMAIN MORE VERTICALLY STACKED WITH UPPER LEVEL DIFFLUENCE
ALLOWING FOR DEEPER CONVECTIVE CORES SUPPORTING UP TO 2.5"/HR
RATES.  GIVEN ONGOING FLOODING...AND ADDITIONAL 2-4" OF RAIN OVER
THE NEXT 4-6 HOURS IS LIKELY TO COMPOUND THE ONGOING SITUATION AS
THE WARM CONVEYOR BELT SLOWLY SHIFTS EASTWARD WITH TIME. 

GALLINA

ATTN...WFO...BMX...JAN...LIX...MOB...TAE...

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

LAT...LON   32438829 32118634 31348582 30208571 30338647
            30278692 30208745 30148802 30308819 31188868
            31658908 32048905