MESOSCALE PRECIPITATION DISCUSSION 0206
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
136 PM EDT SUN MAY 27 2018

AREAS AFFECTED...EASTERN WV...SOUTH-CENTRAL PA...NORTHERN MD...DE

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

VALID 271735Z - 272335Z

SUMMARY...POTENTIAL FOR TRAINING CONVECTION AND HEAVY RAINFALL IS
EXPECTED TO INCREASE THIS AFTERNOON.

DISCUSSION...SOUTHEASTERLY FLOW CONTINUES TO SUPPORT DEEPENING
MOISTURE ALONG A BACKDOOR COLD FRONT THAT HAS PUSHED SOUTHEAST
ACROSS SOUTHERN NJ AND SOUTHEASTERN PA THIS AFTERNOON.  LATEST SPC
MESOANALYSIS SHOW PWS OF 2 INCHES ACROSS THE CENTRAL DELMARVA AND
SOUTHERN NJ.  LATEST RUNS OF THE RAP SHOW PERSISTENT SOUTHERLY
INFLOW MAINTAINING THESE HIGH MOISTURE VALUES...WITH AMPLE
INSTABILITY AS WELL THROUGH THE AFTERNOON HOURS.  HI-RES MODELS
SHOW THIS MOIST/UNSTABLE AIRMASS INTERACTING WITH A STRING OF WEAK
WAVES MOVING ALONG THE BASE OF A BROAD SHORTWAVE TROUGH
TRANSLATING ACROSS SOUTHERN PA...SUPPORTING TRAINING CONVECTION
AND  THE POTENTIAL FOR HEAVY AMOUNTS AND FLASH FLOODING ACROSS THE
REGION.  FOR THE PERIOD ENDING 00z MON...THE LATEST HI-RES
CONSENSUS...INCLUDING RECENT RUNS OF THE OPERATIONAL AND
EXPERIMENTAL HRRR...SHOWS A SIGNIFICANT SIGNAL FOR 6-HR AMOUNTS OF
1-2 INCHES...WITH LOCALLY HEAVIER AMOUNTS WITHIN THE HIGHLIGHTED
REGION. HREF NEIGHBORHOOD PROBABILITIES FOR AMOUNTS OF 2 INCHES OR
GREATER ARE WELL ABOVE 50 PERCENT ACROSS NORTHEASTERN MD DURING
THIS PERIOD.  ANTECEDENT WET CONDITIONS WILL HEIGHTEN THE
POTENTIAL FOR FLASH FLOODING FOR PORTIONS OF THE REGION.

PEREIRA

ATTN...WFO...AKQ...CTP...LWX...PHI...

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

LAT...LON   40157805 39727644 38837513 38327530 38697623
            38967680 39547812