MESOSCALE PRECIPITATION DISCUSSION 0105
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
815 PM EDT SUN APR 15 2018

AREAS AFFECTED...ERN SC...CENTRAL NC...SRN VA

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

VALID 160015Z - 160345Z

SUMMARY...THE PIECES WERE IN PLACE FOR A 2-3 HOUR PERIOD OF
TRAINING HEAVY RAINFALL...INCLUDING OVER METRO RALEIGH. RAPID
ACCUMULATION OF UP TO 3 AND POSSIBLY EVEN 4 INCHES OF RAIN COULD
LEAD TO FLASH FLOODING.

DISCUSSION...AT 00Z RADAR AND SATELLITE IMAGERY SHOWED FEATURES
THAT HAD ALIGNED INTO A WORRISOME PATTERN FOR RALEIGH NC...AND
ALONG A LINE EXTENDING DOWN TO NEAR FLORENCE SC...AND UP TO
CLARKSVILLE VA. THE EVENTS OVER THE NEXT FEW HOURS...THROUGH
ROUGHLY 03Z...WILL NOT BE PARTICULARLY LONG LIVED...BUT STORMS IN
THIS REGION SHOULD BE EFFICIENT HEAVY RAIN PRODUCERS. A BROAD
FIELD OF 500 J/KG-PLUS MIXED LAYER CAPE WAS AVAILABLE IN THE
INFLOW...WITH AIR CHARACTERIZED BY AT LEAST 1.4 INCH PW VALUES AND
BOTTOM-WEIGHTED VERTICAL THERMODYNAMIC PROFILES / LITTLE HAIL
PRODUCTION. UPSTREAM...SATELLITE IMAGERY AND RAP FORECASTS
INDICATED A WELL DEFINED DIFLUENT UPPER LEVEL FLOW PATTERN
ASSOCIATED WITH AN APPROACHING SHORTWAVE TROUGH LIFTING UP THE
EAST SIDE OF THE SYNOPTIC TROUGH. CLOUD TOPS WERE COOLING PER
GOES-16 SWIR CHANNEL...WITH RADAR-BASED ECHO TOP ESTIMATES GREATER
THAN 30 KFT. AN INFLECTION HAD DEVELOPED IN THE RADAR
REPRESENTATION...SUCH THAT TRAINING IS LIKELY TO
PERSIST...INCLUDING OVER RALEIGH...UNTIL THE UPPER SHORTWAVE
SWINGS THROUGH...BY 03-04Z PER THE RAP 700 MB WINDS AND UPPER
DIFLUENCE FIELDS.

GIVEN RADAR BASED ESTIMATES OF 1.50 TO 2.00 INCHES PER HOUR FROM
KRAX AS OF 00Z...ANY GIVEN LOCATION THAT SEES TRAINING ECHOES
COULD EASILY PICK UP MORE THAN 3 INCHES OF RAIN IN A SHORT
PERIOD...AND FLASH FLOODING IS POSSIBLE.

BURKE

ATTN...WFO...AKQ...CAE...CHS...ILM...RAH...RNK...

ATTN...RFC...MARFC...SERFC...

LAT...LON   37177828 36817738 34477867 33397995 33947993
            35607946