MESOSCALE PRECIPITATION DISCUSSION 0364
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
823 AM EDT THU JUN 22 2017

AREAS AFFECTED...SOUTHEAST MS...PARTS OF WESTERN AND SOUTHERN AL

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

VALID 221220Z - 221730Z

SUMMARY...A TRAINING BAND OF VERY HEAVY RAINFALL WILL PERSIST OVER
THE NEXT SEVERAL HOURS. ADDITIONAL FLASH FLOODING IS LIKELY.

DISCUSSION...THE EARLY MORNING EXPERIMENTAL GOES-16 10.3 MICRON/IR
IMAGERY SHOWS A NARROW TRAINING BAND OF COLD TOPPED CONVECTION
EXTENDING FROM THE OFFSHORE WATERS OF THE NORTHERN GULF OF MEXICO
NORTH UP ACROSS FAR SOUTHEAST MS AND APPROACHING THE MS/AL BORDER.
MUCH LIKE THE CONVECTIVE BAND FARTHER EAST OVER SOUTHEAST AL...THE
ACTIVITY IS BEING FOCUSED BY AN AXIS OF RELATIVELY ENHANCED LOW TO
MID LEVEL CONVERGENCE ASSOCIATED WITH THE DEEP LAYER SOUTHERLY
FLOW ACROSS THE CENTRAL GULF COAST STATES TO THE EAST OF THE
CENTER OF T.S. STORM CINDY. ADDITIONALLY...THERE IS SOME
RELATIVELY DIVERGENT FLOW ALOFT HELPING TO FOSTER SOME LARGER
SCALE ASCENT. DESPITE MODEST INSTABILITY WITH 500 TO 1000 J/KG OF
CAPE...THE COLUMN IS EXTREMELY MOIST WITH PWATS OF 2.2 TO 2.4
INCHES AND THIS IS FACILITATING EXTREMELY HEAVY RAINFALL RATES.

THE CURRENT CONVECTIVE BAND WILL CONTINUE TO SUSTAIN ITSELF
THROUGH THE MIDDAY WITH A VERY GRADUAL EASTWARD SHIFT AS THE
DEEPER LAYER MEAN FLOW SLOWLY VEERS. THIS WILL ALLOW PARTS OF FAR
SOUTHEAST MS AND ADJACENT AREAS OF FAR WESTERN AND SOUTHERN AL TO
SEE ADDITIONAL TRAINING CONVECTION WITH VERY HEAVY RAINFALL.

RAINFALL RATES OF UP TO 3 INCHES/HR WILL BE POSSIBLE GIVEN THE
EXTREMELY MOIST COLUMN...AND WITH THE TRAINING MODE OF THE
CONVECTION...ADDITIONAL AMOUNTS THROUGH MIDDAY MAY LOCALLY
APPROACH 6 INCHES. GIVEN THE SATURATED SOIL CONDITIONS AT THIS
POINT...ANY ADDITIONAL RAINFALL WILL LIKELY RESULT IN MORE FLASH
FLOODING.

ORRISON

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

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

LAT...LON   33378815 33278747 32558727 30768762 30128812
            30118882 30458912 31578888 32818865