MESOSCALE PRECIPITATION DISCUSSION 0501
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
1059 PM EDT THU JUL 28 2016
 
AREAS AFFECTED...VIRGINIA...EXT SE MARYLAND...S DELMARVA PENINSULA 
 
CONCERNING...HEAVY RAINFALL...FLASH FLOODING POSSIBLE 
 
VALID 290300Z - 290800Z
 
SUMMARY...ONGOING CONVECTION AND UPSTREAM SYNOPTIC SETUP SUPPORTS
TRAINING CONVECTION AND POSSIBILITY FOR FLASH FLOODING CONDITIONS.

DISCUSSION...SURFACE SETUP SUGGESTS A WEAK MCV DEVELOPING ALONG
OLDER OUTFLOW BOUNDARY NEAR S TIP OF ST. MARY'S COUNTY MD WHICH
HAS SUPPORTED LOCAL BACKING AND INCREASED MOISTURE CONVERGENCE TO
ENHANCE CONVECTION ALONG THE NORTHERN NECK OF E VA AT THIS TIME. 
WV AND RADAR MOSAIC SUPPORTS A SYNOPTIC VORT CENTER ACROSS S WV
PRODUCING EXCELLENT DPVA AS WELL AS SUPPORTING LOW LEVEL
CYCLOGENSIS AT AN INFLECTION POINT NEAR A SW-NE SURFACE BOUNDARY
FROM SW VA ACROSS TO THE INFLECTION NEAR KRIC.  THIS
INFLECTION/SYNOPTIC ASCENT WILL SUPPORT KEEPING ORIENTATION OF
BOUNDARY FAIRLY STEADY AS LOW LEVEL SOUTHERLY FLOW UTILIZE THE
BOUNDARY FOR ISNETROPIC ASCENT AND SUPPORT INCREASING CONVECTIVE
COVERAGE TAPPING REMAINING MLCAPE IN THE 1500-2000 J/KG RANGE. 
ADDITIONALLY CLOUD BEARING FLOW IS FAIRLY UNIDIRECTIONAL AND
PARALLEL TO THE BOUNDARY TO SUPPORT TRAINING OF SAID CONVECTION
THOUGH WITH SOME OUTFLOW/COLD POOL GENERATION PROPAGATION MAY BE A
BIT SOUTH AND NOT PERFECTLY IDEAL.  TDS IN THE MID TO UPPER 70S
AND NICELY SATURATED LOW LEVEL PROFILES SUPPORT AN AXIS OF HIGHER
TPWS NEAR OR ABOVE 2" FROM KLYH/KDAN ACROSS THE SOUTHERN DELMARVA
ALLOWING FOR EFFICIENT RAINFALL PRODUCTION WITH RATES UP TO 2"/HR.
 THIS COMBINATION MAY SUPPORT ECLIPSING OF LOCAL FFG VALUES AND
POSE AREAS OF FLASH FLOODING CONCERNS...PARTICULARLY ACROSS THE
RICHMOND METRO OVER THE NEXT FEW HOURS. 

HI-RES CAMS ARE WELL DISPLACED TO THE NORTH...THOUGH MOST ALSO
SUGGEST THE SYNOPTIC SHORTWAVE LOCATION WAS TO BE IN FAR N
WV...AND WITH AVAILABLE MOISTURE/INSTABILITY FURTHER SOUTH...THE
MAGNITUDES OF THE HI-RES CAMS MAY STILL BE USEFUL WITH HRRR
PARALLEL GEM REGIONAL  ARW/NMMB ALL SUGGESTING 2-4" ACROSS A
NARROW CORRIDOR GIVEN THE SHIFT SOUTH TOWARD REALITY.  

GALLINA

ATTN...WFO...AKQ...LWX...RNK...

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

LAT...LON   38367553 38297498 37507502 37157566 36957787 
            37007859 37247914 37727874 37947821 38077743 
            38327608