MESOSCALE PRECIPITATION DISCUSSION 0142
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
809 PM EDT SUN JUN 30 2013
 
AREAS AFFECTED...SC...NC...VA...FAR EASTERN TN...EASTERN
WV...WESTERN MD...WASH DC...SOUTHERN PA 
 
CONCERNING...HEAVY RAINFALL...FLASH FLOODING POSSIBLE 
 
VALID 010008Z - 010608Z
 
SUMMARY...INCREASING LARGE SCALE LIFT AND SUFFICIENT INSTABILITY
WILL YIELD LOCALLY HEAVY RAIN DESPITE NIGHTFALL. FLASH FLOODING IS
POSSIBLE DURING THE OVERNIGHT HOURS.

DISCUSSION...THE GLOBAL MODELS FIND AGREEMENT WITH THE RAP...AND
ALL SEEM TO HAVE A GOOD HANDLE ON LARGE SCALE ASCENT THAT WILL
OCCUR AS A SHORTWAVE TROUGH LIFTS NORTH FROM THE CAROLINAS
BEGINNING THIS EVENING. COVERAGE OF NEW CONVECTION SHOULD INCREASE
PARTICULARLY ALONG THE EASTERN SLOPES OF THE APPALACHIANS OWING TO
UPGLIDE ON THE 300 K SURFACE...WHICH THE NAM DEPICTS FROM WESTERN
NC TO WESTERN MD/SOUTHERN PA BY 03Z. HI-RES MODELS FOCUS QPF IN
THIS ZONE.

FARTHER EAST...ESTABLISHED COLD POOLS IN CENTRAL NC AND CENTRAL VA
WILL CONTINUE TO SERVE AS FOCI FOR NEW UPDRAFT DEVELOPMENT AS THE
LOW LEVEL AIR/INFLOW OVER EASTERN NC/VA REMAINS SUFFICIENTLY
UNSTABLE AND UNCAPPED WITH DEWPOINTS IN THE LOWER 70S. THOUGH IT
WOULD BE UNUSUAL FOR NEW SFC BASED CONVECTION TO FORM IN THE
EVENING HOURS TOWARD WASH DC AND MD...A FEW SMALL COLD POOLS WERE
ALREADY ESTABLISHED THERE...LEADING TO THE POSSIBILITY OF NEW AND
SLIGHTLY ELEVATED ACTIVITY AS LOW/MID LAYER LIFT INCREASES FROM
THE SOUTH TOWARD 02-05Z.

WITHIN THE BROAD REGION OUTLINED BY THIS MPD...SHEAR IN THE CLOUD
LAYER SHOULD PROVE SUFFICIENT FOR SOME UPDRAFT ROTATION TO RESULT
IN SLOW MOVEMENT ENE...WHILE MCS MOTIONS ARE PREDICTED AT ONLY
5-10 KT TOWARD THE NORTH. EXPECT RELATIVELY LOW TOPPED CELLS WITH
VERY EFFICIENT RAINFALL PRODUCTION AS PW VALUES INCREASE TOWARD
1.75 INCHES OR MORE...SUPPORTING RAIN RATES NEAR 2 INCHES PER HOUR.

BURKE

ATTN...WFO...AKQ...CTP...LWX...RAH...ILM...RNK...PBZ...RLX...
CAE...GSP...MRX...

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

LAT...LON   34338034 35177881 36097787 37327705 38277685 39157683
            39887678 40287700 40417800 40067921 39587959 38398058
            36918188 36028279 35508267 35298204 34998159 34478134
            34148115 34338034