MESOSCALE PRECIPITATION DISCUSSION 0385
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
948 AM EDT MON JUN 27 2016
 
AREAS AFFECTED...PORTIONS OF WV AND WESTERN VA 
 
CONCERNING...HEAVY RAINFALL...FLASH FLOODING POSSIBLE 
 
VALID 271347Z - 271947Z
 
SUMMARY...THUNDERSTORMS ARE SLOWLY INCREASING IN COVERAGE AND
INTENSITY ACROSS THE REGION.  CONSIDERING THE SATURATED GROUND
CONDITIONS, FLASH FLOODING IS POSSIBLE.

DISCUSSION...THUNDERSTORMS ARE DEVELOPING NEAR AND AHEAD OF A
SURFACE TROUGH ACROSS SOUTHEAST OH, WV, AND NEAR THE KY/OH BORDER.
 THE 12Z SOUNDING UPSTREAM AT ILN SHOWS FAIRLY UNIDIRECTIONAL FLOW
WITH HEIGHT.  PER SPC MESOANALYSES, CIN HAS ALREADY ERODED
UPSTREAM ACROSS SOUTHERN OH AND IS ERODING ACROSS SOUTHERN WV. 
PRECIPITABLE WATER VALUES OF 1.2-1.8" LIE ACROSS THE REGION, PER
GPS DATA AND THE 12Z RLX SOUNDING.  THIS WOULD EQUATE AT SEA LEVEL
TO OVER 2" PRECIPITABLE WATER VALUES FOR THE HIGHER TERRAIN OF WV.
 SUNNY SKIES ARE LEADING TO SLOWLY BUILDING INSTABILITY, WITH
MLCAPES CURRENTLY IN THE 500-1000 J/KG RANGE ACROSS SOUTHERN OH
AND WESTERN WV.  INFLOW AT 850 HPA IS SOMEWHAT CONVERGENT AND ON
THE ORDER OF 15 KTS.

AS THE SURFACE/850 HPA BOUNDARIES AND MOISTURE PLUME MOVE FARTHER
INTO THE AREA LATER TODAY, 0-6 KM BULK SHEAR RISES INTO THE 20-30
KT RANGE, WHICH COULD TRY TO ORGANIZE THE OTHERWISE PULSE
CONVECTION EXPECTED IN THE REGION.  MLCAPES ARE EXPECTED TO RISE
TO ~2000 J/KG DUE TO DAYTIME HEATING.  THE 06Z GFS GALVEZ- DAVISON
INSTABILITY INDEX SHOWS RISING VALUES THROUGH THE DAY, PEAKING
ABOVE 50 TOWARDS 21Z, WHICH SUPPORTS THE DEVELOPMENT OF NUMEROUS
THUNDERSTORMS.  THE HEAVY RAIN EVENT THIS PAST THURSDAY HAS
SATURATED SOILS, WITH THE RLX OFFICE INDICATING THREE HOUR RAIN
RATES OF 1.25" BEING POTENTIALLY PROBLEMATIC FROM A FLASH FLOOD
STANDPOINT, SLIGHTLY BELOW CURRENT FLASH FLOOD GUIDANCE VALUES. 
THE MESOSCALE/CAM GUIDANCE SHOWS LOCAL AMOUNTS OF 2-3" ACROSS
PORTIONS OF WV, WESTERN MD, AND WESTERN VA, WHICH COULD FALL
QUICKLY.  WITH HOURLY RAIN RATES UP TO 2" IN AREAS OF CELL MERGERS
OR SHORT PERIODS OF CELL TRAINING, FLASH FLOODING IS CONSIDERED
POSSIBLE.

ROTH

ATTN...WFO...CTP...LWX...PBZ...RLX...RNK...

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

LAT...LON   40027900 39517867 39347820 39627813 39407756 
            38467838 37747883 37508018 37088020 36928033 
            37108068 37258144 37888212 38618178 38978150 
            39128087 39738046 39848005