Quantitative Precipitation Forecast
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FOUS30 KWBC 270702
QPFERD

EXCESSIVE RAINFALL DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
302 AM EDT SUN JUL 27 2014

...VALID 06Z SUN JUL 27 2014 - 12Z MON JUL 28 2014...
...REFERENCE AWIPS GRAPHIC UNDER...DAY 1 EXCESSIVE RAINFALL...


SLIGHT RISK OF RAINFALL EXCEEDING FFG TO THE RIGHT OF A LINE FROM
20 SW HLG 25 S AOO 20 NNE ROA 30 W LNP 30 S LUK 20 NW UNI
20 SW HLG.

SLIGHT RISK OF RAINFALL EXCEEDING FFG TO THE RIGHT OF A LINE FROM
40 ENE CAO 40 ENE LVS 15 SSE SKX 35 SSE MYP 40 W AFF 30 ESE COS
30 SW LAA 40 ENE CAO.


...OH VALLEY TO THE UPSLOPE REGION OF THE APPALACHIANS...

THE MODELS DEVELOP ADDITIONAL CONVECTION LATER OVER FROM THE
SOUTHERN GREAT LAKES TO THE OH AS THE BETTER JET DYNAMICS APPROACH
THE REGION WITH BETTER INSTABILITY.  WITH PRECIPTABLE WATER VALUES
IN THE 1.75 TO 2 INCH RANGE...LOCALLY HEAVY RAINFALL WILL BE
POSSIBLE...ESPECIALLY IN THE UPSLOPE REGIONS OF THE CENTRAL
APPALACHIANS WHERE THE MOISTURE TRANSPORT INTO THE COMPLEX TERRAIN
IS MAXIMIZED LATER TODAY AND TONIGHT. ENSEMBLES SUPPORT POCKETS OF
2 INCHES OR MORE OVER WV WHICH SHOULD BE ENOUGH TO PRODUCE AREAS
WHERE RAFL EXCEEDS FLASH FLOOD GUIDANCE.

...WESTERN NY...

A SHORTWAVE ROTATING AROUND THE PERIPHERY OF A CLOSED LOW OVER
QUEBEC WILL PROVIDE THE FOCUS FOR A SEPARATE AREA OF SHOWERS AND A
FEW THUNDERSTORMS AS IT MOVES FROM THE EASTERN GREAT LAKES THIS
MORNING TO EASTERN NEW ENGLAND AND THE CANADIAN MARITIMES BY LATE
THIS EVENING.  GOOD SOUTHERLY FLOW AHEAD OF THE SHORTWAVE AND
AHEAD OF THE AMPLIFYING TROF WILL TRANSPORT MOISTURE INTO THE
AREA...AND HIGHER RESOLUTION GUIDANCE IS SUGGESTING LOCALIZED
HIGHER AMOUNTS IN PARTS OF INTERIOR NEW ENGLAND.  SAW LITTLE
REASON TO ARGUE WITH THAT IDEA AND LARGELY USED WPC PSEDUO BIAS
CORRECTED GUIDANCE HERE.

THE WPC PSEDUO BIAS CORRECTED SHOWED A FAIRLY BROAD SWATH OF 2 AND
3 INCH AMOUNTS OVER PARTS OF WESTERN NY WHICH LOOKED OVER DONE.
HOWEVER SOME DOWNPOURS MAY BE CAPABLE OF PRODUCING LOCALIZED
PROBLEMS DUE TO RUNOFF.  ALSO THINK THE POSSIBILITY EXISTS FOR
ISOLATED RUNOFF PROBLEMS MAY OCCUR IN THE HILLY TERRAIN OF
INTERIOR NEW ENGLAND GIVEN AMOUNT OF MOISTURE BEING DRAWN INTO THE
AREA.

...SOUTHWESTERN U.S TO COLORADO...

WITH THE AMPLIFICATION OF THE UPR TROF THRU THE GREAT LAKES...THE
PRONOUNCED UPR RIDGE OVER THE SRN ROCKIES IS EXPECTED TO EXPAND
NWD INTO THE NRN INTERMOUNTAIN REGION THIS PD. LINGERING MSTR
TRAPPED UNDER THE BUILDING RIDGE WILL MAINTAIN THREAT OF ISOLD TO
SCTD CONVECTION THRU MUCH OF THE 4 CORNERS REGION..MOSTLY DIURNAL
IN NATURE.

THERE ARE SOME INDICATIONS OF WEAK S/WV ENERGY TRACKING WNWWD
ALONG THE SRN PERIPHERY OF THE UPR RIDGE ACRS NRN MEX THAT MAY
TEND TO ENHANCE ACTIVITY OVER SE AZ/SW NM SUN AFTN..OTHERWISE
FORCING REMAINS ILL DEFINED.  ACRS CO AND THE ADJACENT HIGH
PLAINS....THERE IS GENL MODEL AGREEMENT IN SHOWING ENHANCED SE/E
UPSLOPE FLOW BEHIND SWD MOVING COLD FRONT INTO THE ERN SLOPES OF
THE CNTL/SRN CO MTNS ON SUN WITH PWS INCREASING TO OVER 1.5 INCHES
OVER SE CO SUN AFTN.  WHILE THE SPREAD IN MODEL GUIDANCE WAS STILL
FAIRLY LARGE..THE GFS/ARW AND STORM SCALE ENSEMBLE AND 27 KM ECMWF
ALL GENERATED AT LEAST AN INCH AND A HALF OF QPF OVER SOUTHEAST CO
INTO NORTHEAST NM LATER THIS EVENING AND INTO THE OVERNIGHT HOURS
WHICH POINTS TO THE POTENTIAL OF SOME FLASH FLOODING.

BANN


BURKE/SULLIVAN
$$




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