Graphic for MPD #0656

MESOSCALE PRECIPITATION DISCUSSION 0656
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
444 PM EDT TUE AUG 08 2017

AREAS AFFECTED...SOUTHEAST MS....CENTRAL/SOUTHERN AL

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

VALID 082040Z - 090030Z

SUMMARY...SLOW-MOVING SHOWERS AND THUNDERSTORMS WILL CONTINUE THIS
EVENING. HEAVY RAINFALL RATES UP TO 3 INCHES/HR AND THE SLOW CELL
MOTION MAY RESULT IN SOME FLASH FLOODING CONCERNS.

DISCUSSION...THE LATE-DAY EXPERIMENTAL GOES-16 0.64 MICRON/VIS
IMAGERY SHOWS NUMEROUS SHOWERS AND THUNDERSTORMS GAINING SOME
ORGANIZATION OVER PARTS OF SOUTHERN MS AND CENTRAL/SOUTHWEST AL.
THE ACTIVITY IS FOCUSING WITHIN A VERY MOIST/UNSTABLE AIRMASS
WHERE STRONGER DIURNAL HEATING OVER THE LAST COUPLE OF HOURS HAS
ENHANCED SURFACE-BASED INSTABILITY. THE LOW LEVEL FLOW IS ALSO
LARGELY CONFLUENT AND THUS PROVIDING SOME ADDITIONAL SURFACE
CONVERGENCE/FORCING.

PWATS ARE BETWEEN 2.2 AND 2.4 INCHES AND WITH SUCH A DEEP COLUMN
OF MOISTURE...RAINFALL RATES ARE QUITE HEAVY AND WILL BE
APPROACHING 3 INCHES/HR IN SOME CASES WITHIN THE STRONGER
CONVECTIVE CORES OVER THE NEXT COUPLE OF HOURS.

THE HIRES MODEL GUIDANCE IS DOING A VERY POOR JOB OF HANDING THE
CURRENT ACTIVITY...BUT THE THINKING IS THAT AREAS OF SOUTHERN MS
EAST-NORTHEAST ACROSS AREAS OF CENTRAL/SOUTHERN AL WILL SEE A
RELATIVELY ORGANIZED AXIS OF CONVECTION INTO THE EARLY EVENING
HOURS WITH SOME LOCALLY VERY HEAVY RAINFALL TOTALS. EXPECT AS MUCH
AS 3 TO 5 INCHES OF RAIN WITH ISOLATED HEAVIER AMOUNTS POSSIBLE.
THIS WILL RESULT IN SOME AREAS OF EXTENSIVE RUNOFF AND POSSIBLE
FLASH FLOODING.

ORRISON

ATTN...WFO...BMX...FFC...JAN...MOB...TAE...

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

LAT...LON   32858674 32758557 32208502 31518521 31258563
            31048675 30908789 30958872 31028944 31108980
            31288992 31478973 31828900 32028832 32578747
           


Last Updated: 444 PM EDT TUE AUG 08 2017