Graphic for MPD #0252

MESOSCALE PRECIPITATION DISCUSSION 0252
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
521 AM EDT SUN MAY 21 2017

AREAS AFFECTED...FAR NORTHEAST GA...WESTERN CAROLINAS

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

VALID 210920Z - 211420Z

SUMMARY...HEAVY RAINFALL MAY LEAD TO AN ISOLATED FLASH FLOOD
THREAT ACROSS PORTIONS OF FAR NORTHEAST GA...WESTERN SC AND FAR
SOUTHERN NC INTO THE EARLY MORNING HOURS.

DISCUSSION...AS OF 09Z AN MCV HAD MOVED INTO WEST GA...WITH A
WEAKENING CONVECTIVE LINE EXTENDING SOUTH OF THIS CIRCULATION INTO
SOUTHWEST GA AND THE FL PANHANDLE. TO THE EAST OF THE MCV
INCREASED LOW LEVEL MOISTURE TRANSPORT HAS RESULTED IN AN UPTICK
IN CONVECTIVE ACTIVITY ACROSS EASTERN GA AND WESTERN SC. RADAR AND
IR IMAGERY SHOWS THAT THIS ACTIVITY IS NOT ALL THAT DEEP...HOWEVER
WITH MOIST PROFILES AND PWAT VALUES AROUND 1.75"...THESE CELLS
WILL LIKELY STILL BE EFFICIENT RAINFALL PRODUCERS. CELL MOTIONS
WILL BE OFF TO THE NORTHEAST...HOWEVER THE WIDESPREAD NATURE OF
THE ACTIVITY WILL LIKELY RESULT IN CELL MERGERS...LOCALLY
INCREASING RAINFALL TOTALS.

RECENT RUNS OF THE HRRR HAVE BEEN PRETTY CONSISTENT IN DEPICTING A
REGION OF LOCALLY HEAVIER RAINS OVER PORTIONS OF NORTHEAST GA INTO
THE WESTERN CAROLINAS...WITH JUST SOME RUN TO RUN PLACEMENT
DIFFERENCES. DO THINK THAT THE 08Z HRRR IS A BIT TOO FAR NORTHWEST
WITH THE QPF MAX. IN GENERAL EXPECTING TO SEE WIDESPREAD 1-2"
TOTALS ACROSS THE MPD AREA...WITH ISOLATED 2-4" AMOUNTS WHERE
MERGERS ARE MAXIMIZED. GIVEN THE HIGH FLASH FLOOD GUIDANCE OVER
THE AREA WOULD GENERALLY ONLY ANTICIPATE ISOLATED FLASH FLOOD
CONCERNS TO DEVELOP FROM THIS ACTIVITY. CURRENT INDICATIONS ARE
THAT WE MAY SEE A DECREASE IN INTENSITY AFTER 14Z AS LOW LEVEL
MOISTURE TRANSPORT WANES.

CHENARD

ATTN...WFO...CAE...FFC...GSP...

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

LAT...LON   35658173 35328145 35148140 34038162 33238200
            33378307 33768330 34088321 34648282 35158256
            35588236


Last Updated: 521 AM EDT SUN MAY 21 2017