Quantitative Precipitation Forecast
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000
FOUS30 KWBC 050756
QPFERD

EXCESSIVE RAINFALL DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
354 AM EDT THU MAY 05 2016

...VALID 12Z THU MAY 05 2016 - 12Z FRI MAY 06 2016...
...REFERENCE AWIPS GRAPHIC UNDER...DAY 1 EXCESSIVE RAINFALL...


SLIGHT RISK OF RAINFALL EXCEEDING FFG TO THE RIGHT OF A LINE FROM
20 NW MTV 15 W LWB W22 25 SSW 2G4 15 WNW SHD 15 SW FVX 15 E ASJ
20 ENE OCW EWN 15 SW GSB 10 S BUY 20 NW MTV.


...CENTRAL APPALACHIANS INTO PORTIONS OF THE VA/NC PIEDMONT AND NC
COASTAL PLAIN...

THE 546 DM CLOSED LOW DROPPING TOWARD THE SOUTHERN APPALACHIANS
REPRESENTS LARGE ANOMALIES...4 STANDARD DEVIATIONS BELOW THE
CLIMATOLOGICAL MEAN...BY THE TIME IT DIGS INTO THE SOUTHEAST
STATES. PERSISTENT DIFLUENT FLOW NEAR AND JUST EAST/NORTHEAST OF
THE CLOSED LOW WILL SUPPORT RELATIVELY FOCUSED AND PERSISTENT
RAINFALL FROM THE CENTRAL TO SOUTHERN APPALACHIANS AND IN THE
PIEDMONT OF VA/NC. WITH THE LARGER SCALE WARM CONVEYOR BELT WELL
OFF THE EAST COAST...HOWEVER...THIS SYSTEM WILL WORK WITH VERY
MODEST MOISTURE AND WEAK INSTABILITY...SUCH THAT HEAVY OR EXTREME
RAINFALL IS UNLIKELY.

IN TERMS OF THE 00Z MODEL SUITE...THE GFS REMAINED A WET OUTLIER
WITH ITS 24-HOUR 3-4 INCH MAXIMUM... THIS TIME CENTERED OVER THE
NORTHERN NC COASTAL PLAIN. WPC QPF IN THIS REGION WAS COMPRISED
FROM A BLEND OF THE 00Z ECMWF AND PARALLEL GFS...WHICH NOTED A
MAXIMA BETWEEN 2-2.5"...COINCIDING TO WHERE THE BEST DIURNAL
INSTABILITY IS EXPECTED TO BE LATER THIS AFTN INTO THE EVENING
(MUCAPES 400-800 J/KG).

AS FAR AS THE EXCESSIVE RAINFALL POTENTIAL ON DAY 1...WPC WILL
INCLUDE A MORE CONFINED/NARROW SLIGHT RISK AREA COMPARED TO THE
DAY 2 OUTLOOK FROM YESTERDAY -- STRETCHING FROM PORTIONS OF
EASTERN WV/WESTERN VA SOUTHEAST INTO NORTH-CENTRAL AND NORTHEAST
NC...OR ALONG THE AXIS OF BEST DIFFLUENCE AND DIVERGENCE ALOFT
EAST OF THE UPPER LOW...AND ALONG THE WEAK INSTABILITY AXIS WITH
700-500 MB LAPSE RATES ~7C/KM. PROBABILITIES OF 3 AND 6 HOURLY
QPF>FFG EXCEEDANCE ARE LOW PER THE LATEST SSEO MEAN (30 PCT OR
LESS)...WITH THE LOWER FFG VALUES THE MAIN FACTOR OVER THE
NORTHERN HALF OF THE SLIGHT RISK AREA...WHILE THE HIGHER QPF PER
MODEL CONSENSUS BEING MORE OF A FACTOR OVER NC.

HURLEY
$$





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