MESOSCALE PRECIPITATION DISCUSSION 0244
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
329 PM EDT THU MAY 31 2018

AREAS AFFECTED......SOUTHEAST TN AND NORTHEAST AL ACROSS NORTHERN
GA AND NORTHWEST SC...

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

VALID 311928Z - 010028Z

SUMMARY...HEAVY SHOWERS/STORMS ARE FORECAST TO MOVE OUT OF THE
SOUTHERN APPALACHIANS
INTO ADJACENT AREAS OF SOUTHEAST TN....NORTHEAST AL....NORTHERN
GA...AND THE WESTERN CAROLINAS.

PRIOR RAINS HAVE RESULTED IN AREAS PRONE TO FLASH FLOODING SO
PATCHES OF 1-3 INCHES OF RAIN COULD CAUSE FLOODING IN THE WESTERN
CAROLINAS.  2-4 INCHES OF RAIN ARE POSSIBLE IN PORTIONS OF
SOUTHEAST TN TO NORTHERN GA AND NORTHEAST AL.

DISCUSSION...REGIONAL RADARS AND SATELLITE HAVE SHOWN AN INCREASE
IN SHOWERS/STORMS ACROSS SOUTHEAST TN AND IN THE SOUTHERN
APPALACHIANS TO ADJACENT AREAS OF THE WESTERN CAROLINAS. THESE
STORMS WILL MOVE SLOWLY SOUTHEAST.  SLOW MOTION AND LOCALIZED
TRAINING COULD LEAD TO HEAVY RAIN AND FLASH FLOODING CONCERNS.

DIURNAL DESTABILIZATION AND DEEP MOISTURE WITH MID 70S DEWPOINTS
SUPPORT ADDITIONAL SHOWERS/STORMS...AIDED BY LIFT CREATED BY UPPER
LEVEL DIVERGENCE MAXIMA MOVING ACROSS TN INTO AL/GA/WESTERN
CAROLINAS. 

OBSERVED AND FORECAST SOUNDINGS ACROSS NORTHERN GA SHOW
SURFACE-500 MB RELATIVE HUMIDITY OF 80-90 PERCENT...SO SHOWERS
WILL BE EFFICIENT RAINFALL PRODUCERS.

THE WESTERN CAROLINAS TO NORTHEAST GA HAVE RECEIVED HEAVY RAINS
EARLIER THIS WEEK SO ARE PRONE TO FLOODING IF ADDITIONAL HEAVY
RAINS OCCUR.  CLUSTERS OF 1-3 INCHES ARE FORECAST HERE. FORECAST
SOUNDINGS SHOW SURFACE-850 MB WINDS OF 10 KT OR LESS SO SLOW
MOTIONS ARE EXPECTED.

THE SHOWERS/STORMS DROPPING OUT OF TN INTO NORTHERN GA AND LATER
INTO NORTHEAST AL WILL BE FED BY AN IMPRESSIVE 3500-4000 J/KG
MIXED LAYER CAPE IN NORTHERN AL.
WHICH WOULD RESULT IN LOCALIZED HEAVY RAIN TOTALS.  OUTFLOWS FROM
EXISTING CELLS IN SOUTHEAST TN TO ADJACENT NORTHERN GA PROVIDE
WELL DEFINED BOUNDARY LAYER MOISTURE CONVERGENCE...SO ADDITIONAL
SHOWERS/STORMS ARE EXPECTED.

THE NAM CONUS NEST...WRF ARW AND ARW 2 AND THE 16-17Z HIGH RES
RAPID REFRESH SHOW CLUSTERS OF 1-3 INCHES OF RAIN WITH MAXIMA TO 5
INCHES WHERE CELL MERGERS...BRIEF TRAINING OR MORE THAN ONE ROUND
OF SHOWERS/STORMS OCCUR IN SOUTHEAST TN TO NORTHERN GA AND
NORTHEAST AL.

PETERSEN

ATTN...WFO...BMX...FFC...GSP...HUN...MRX...OHX...RAH...RNK...

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

LAT...LON   36508126 36438106 36458070 36198028 35858047
            35248125 35188135 34758220 34378270 33768377
            33708463 34178566 34878693 35478673 35558667
            35738603 35728556 35488459 35358422 35408371
            35588316 35868245 36008212 36198173 36358131