Quantitative Precipitation Forecast
Issued by NWS

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000
FOUS30 KWBC 110831
QPFERD

EXCESSIVE RAINFALL DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
431 AM EDT WED OCT 11 2017

...VALID 12Z WED OCT 11 2017 - 12Z THU OCT 12 2017...
...REFERENCE AWIPS GRAPHIC UNDER...DAY 1 EXCESSIVE RAINFALL...


MARGINAL RISK OF RAINFALL EXCEEDING FFG TO THE RIGHT OF A LINE FROM
10 WSW MRB 20 SW JYO 15 WNW 2W6 15 SW SBY 35 SE OXB 100 ESE WAL
110 ENE FFA 75 ENE FFA 20 NE FFA 20 SSW SFQ 10 NNE AVC
25 SSW FVX 10 NE LYH 15 E EKN 15 ENE MGW 10 NNW LBE 10 SE AOO
20 NNW MRB 10 WSW MRB.


PORTIONS OF THE MID ATLANTIC

CONCERNS CONTINUE FOR ISOLATED EXCESSIVE RAINFALL AMOUNTS IN THE
VICINITY OF THE STATIONARY FRONTAL BOUNDARY FORECAST TO LIE IN A
EAST SOUTHEAST TO WEST NORTHWESTERLY DIRECTION FROM SOUTHEAST
VIRGINIA INTO NORTHWEST VIRGINIA.  THIS FRONT IS EXPECTED TO
STRENGTHEN WITH TIME DAY 1 AS A SECONDARY FRONT MOVING SOUTH
THROUGH THE MID ATLANTIC REINFORCES THE LEAD FRONT FARTHER TO THE
SOUTH.  PW VALUES IN THE VICINITY OF THE BOUNDARY LIKELY TO REMAIN
MUCH ABOVE AVERAGE DURING THE DAY ON WEDNESDAY WITH VALUES 2.5 TO
3 STANDARD DEVIATIONS ABOVE THE MEAN.  TRAINING OF CELLS HAS
OCCURRED IN THE VICINITY OF THIS BOUNDARY EARLY WEDNESDAY
MORNING--WITH THIS POTENTIAL POSSIBLY CONTINUING INTO THE FIRST
FEW HOURS OF THE UPCOMING DAY 1 PERIOD. AFTER THIS---THERE WILL BE
POTENTIAL FOR ADDITIONAL CONVECTION TO FIRE IN THE UNSTABLE
AIRMASS ALONG AND SOUTH OF THE BOUNDARY THROUGH WEDNESDAY AND MOVE
PARALLEL TO THE BOUNDARY.  THE SIMULATED RADARS FROM THE HI RES
GUIDANCE---ARW---NMMB AND HRRR SHOW ADDITIONAL WEST TO EAST MOVING
STORMS THIS PERIOD---ESPECIALLY AROUND AND AFTER 0000 UTC OVER
SOUTHEAST VIRGINIA.  IN AREAS OF TRAINING---HOURLY PRECIP TOTALS
OF 1"+ POSSIBLE---RESULTING IN ISOLATED RUNOFF ISSUES.


ORAVEC
$$





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