Area Forecast Discussion
Issued by NWS Wakefield, VA

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000
FXUS61 KAKQ 232144
AFDAKQ

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE WAKEFIELD VA
444 PM EST TUE DEC 23 2014

.SYNOPSIS...
A WARM FRONT WILL LIFT NORTHWARD THROUGH THE AREA OVERNIGHT
THROUGH WEDNESDAY MORNING AS A LOW PRESSURE SYSTEM STRENGTHENS
WEST OF THE MOUNTAINS. AN ASSOCIATED COLD FRONT WILL CROSS THE
AREA WEDNESDAY NIGHT. HIGH PRESSURE BUILDS BACK IN FROM THE
SOUTHWEST CHRISTMAS DAY THROUGH FRIDAY.

&&

.NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/...
LATEST SFC ANALYSIS SHOWS WEAK LOW PRESSURE JUST OFF THE NJ
COAST...SLOWLY LIFTING NE. SATURATED LOW LEVELS REMAIN BUT VSBYS
HAVE IMPROVED TO AT OR ABOVE 2SM IN MOST AREAS AS FOG HAS LIFTED
AND NOW JUST SEEING MAINLY LOW STRATUS. FOG NOW MOST PREVALENT
OVER THE WATER BUT VSBYS HAVE IMPROVED HERE AS WELL.

EXPECT FOG TO BECOME AN ISSUE AGAIN LATER THIS EVENING OR TONIGHT
AS HIGHER DEW PTS SURGE NORTHWARD TO THE N OF THE APPROACHING WARM
FRONT. SFC WARM FRONT WILL LIFT NORTH ACRS THE REGION LATER
TONIGHT AND WILL ALLOW FOR THE AREA TO BE WARM SECTORED ON WED.
DEEP MOISTURE TRANSPORT OCCURS TONIGHT...RAISED POPS TO NEAR 100%
ALL AREAS...AS MODERATE TO HEAVY RAIN MOVES THROUGH THE REGION...REACHING
SRN AREAS 00-03Z...NRN AREAS AFTER MIDNIGHT. LOWS TONIGHT IN THE
40S MOST AREAS...WITH TEMPERATURES LIKELY TO RISE AFTER MIDNIGHT
(ESP IN SE ZONES).

&&

.SHORT TERM /6 AM WEDNESDAY MORNING THROUGH FRIDAY/...
LATEST RUNS OF THE NAM/GFS/ECMWF AND VARIOUS HIGH RES MODELS
REMAIN IN GOOD AGREEMENT OVERALL W/ THE PATTERN WED/WED NIGHT. A
~995MB SFC LOW OVER THE TN/OH VALLEY WILL TRACK RAPIDLY NNE FROM
AND INTENSIFY THROUGH THE DAY...REACHING THE CENTRAL GREAT LAKES
BY 00Z/THU. OVER AKQ AREA...DEEP SOUTHERLY FLOW WILL
INCREASE...AND SHOULD SCOUR OUT ANY RESIDUAL WEAK LOW LEVEL
WEDGING OVER THE PIEDMONT (WILL MAINTAIN SOME MENTION OF FOG IN
THE AM HRS ACRS THE NW ZONES AS WELL AS THE NRN WATERS). DEW PTS SOAR
INTO THE UPPER 50S TO LOWER-MID 60S BY LATE MORNING/AFTN.  AT
THIS POINT THERE DOES NOT LOOK TO BE MUCH IN THE WAY OF CLEARING
POTENTIAL (HIGH SHEAR BUT VERY MINIMAL CAPE) ON WED TO LEAD TO
SEVERE WX. SPC HAS MUCH OF THE CWA IN A MARGINAL RISK FOR SEVERE
WX...PRIMARILY DUE TO STRONG FLOW IN THE H9 TO H5 WINDS (HIGH SHEAR).
CAPES WILL BE MINIMAL AND TIMING OF FRONT WILL BE WED EVENING/WED
NIGHT...NOT OPTIMAL FOR A SEVERE WX OUTBREAK. WILL CONTINUE TO
MENTION MARGINAL THREAT IN HWO...AND ISO TSTMS WED EVENING/ERLY
THU MORNING AND IT WIL NOT NOT TAKE A LOT TO MIX DOWN ~40+ MPH
WINDS AS THE FRONT PUSHES THROUGH. HIGHS WED INTO THE M-U60S TO
LOWER 70S (CLOSE TO RECORD HIGHS/SEE CLIMATE SECTION). CATEGORICAL
POPS ALL AREAS WED (ALTHOUGH PRECIP MAY SCATTER OUT FOR A TIME IN
THE WARM SECTOR. HIGHEST POPS SHIFTING OFF THE COAST LATER WED
NIGHT AS THE COLD FRONT PUSHES THROUGH AND DRIER AIR MOVES IN FROM
THE WEST BY CHRISTMAS MORNING. SLOWER PASSAGE OF THE FRONT WILL
MAKE FOR VERY MILD MINS CHRISTMAS MORNING WITH LOWS IN THE MID 40S
FAR WEST...TO THE MID 50S SE. SKIES BECOME MOSTLY SUNNY WITH
BREEZY WESTERLY FLOW BY MID/LATE MORNING CHRISTMAS DAY. RAISED
HIGHS TO MID 50S TO LOWER 60S CHRISTMAS DAY AS CAA IS WEAK AND
WILL BE OFFSET BY DOWNSLOPE WARMING (AND DUE TO A WARM BEGINNING).
CLEAR/SEASONABLE THU NIGHT W/ LOWS IN THE UPPER 20S TO MID 30S.
SFC HIGH IN CONTROL/LIGHT WINDS AND MAINLY CLEAR FRI. HIGHS IN THE
50S.

&&

.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
THE MODELS ARE IN GOOD AGREEMENT TO BEGIN THE PERIOD FRIDAY NIGHT
WITH THE STRONG RIDGING OVER THE SOUTHEASTERN US AND HIGH PRESSURE
OVER THE SOUTHEAST...CENTERED OVER EASTERN VA/NC. BUT THE MODELS
STRUGGLE WITH THE BREAKING DOWN OF THE RIDGE WITH THE GFS BREAKING
IT DOWN MUCH MORE QUICKLY THAN THE ECMWF. THE GFS ALLOW THE NEXT
COLD FRONT TO DROP INTO THE ARE SAT NIGHT AND MOVES IT SOUTH OF
THE REGION BY SUNDAY MORNING...SETTING UP AN OVERRUNNING PATTERN
SUNDAY AFTERNOON INTO MONDAY MORNING. THE ECMWF...AND THE 12Z IS
FURTHER NORTH WITH FEATURES THAN 00Z RUN...KEEPS THE RIDGE MUCH
STRONGER OVER THE SE AND DOES NOT ALLOW THE COLD FRONT TO MOVE
THROUGH THE AREA SAT NIGHT. IT STALLS THE FRONT OVER THE AREA ON
SUNDAY AND AS A WAVE OF LOW PRESSURE FORMS ALONG THE BOUNDARY AND
LIFTS NE INTO THE CENTRAL APPALACHIANS...IT PUSHES GULF MOISTURE
INTO THE AREA. THE 00Z ECMWF PUSHED THE WAVE OFF THE COAST BY
MONDAY...BUT THE 12Z RUN LIFTS THE LOW TO THE NORTH AND DRAGS A
COLD FRONT ACROSS THE REGION ON TUESDAY.

SO FOR NOW WITH THE GREAT SPREAD IN THE MODELS...HAVE TRENDED
TOWARD HPC/WPC GUIDANCE...WHICH IS SIMILAR TO THE 00Z ECMWF AND
BROUGHT THE WAVE INTO THE REGION ON SUNDAY AFTERNOON AND EVENING
WITH IT EXITING BY MONDAY AFTERNOON. HAVE INCREASED POPS TO 50%
FOR THAT PERIOD...KEEPING SATURDAY DRY. HAVE ALSO GONE DRY ON
MONDAY NIGHT INTO TUESDAY. THE BIG DIFFERENCE COMES TO
TEMPERATURES AS THE GFS WOULD ALLOW MUCH COLD AIR INTO THE REGION
BEGINNING ON SUNDAY THROUGH TUESDAY. THIS COULD ALSO POTENTIALLY
LEAD TO SOME WINTRY PCPN WITH WAVE ON SUNDAY NIGHT. FOR NOW HAVE
KEPT TEMPERATURES ABOVE FREEZING AND ALL RAIN WITH THE COLD AIR
BEING KEPT MORE TO THE NORTH. FOR TEMPERATURES HAVE ALLOW FOR A
GRADUAL COOL DOWN THROUGH THE PERIOD WITH THE COLDEST AIR ARRIVING
ON TUESDAY WITH HIGHS IN THE 40S.

&&

.AVIATION /21Z TUESDAY THROUGH SUNDAY/...
VARIABLE IFR/MVFR CONDITIONS WILL EXIST THROUGH 00Z WED BEFORE ALL
SITES BECOME LOCKED IN IFR CONDITIONS THROUGH WED MORNING. LIGHT
SE FLOW DEVELOPS TONIGHT WITH HIGH PRESSURE OFFSHORE AND LOW
PRESSURE LIFTING THROUGH THE OHIO VALLEY. GIVEN THIS...IFR
CONDITIONS FEATURING LOW CIGS AND REDUCED VSBY IN AREAS OF -DZ/BR
SHOULD PREVAIL AT LEAST THROUGH TONIGHT AS THERE WILL BE NO
MECHANISM TO SCOUR-OUT LOW- LEVEL MOISTURE. A WARM FRONT/COASTAL
FRONT SLOWLY LIFTS SE-NW ACROSS THE REGION EARLY WEDNESDAY MORNING AS
LOW PRESSURE TRACKS NNE TOWARD THE GREAT LAKES. A GRADUAL
IMPROVEMENT IN CIGS IS POSSIBLE ON THE WARM SIDE OF THE BOUNDARY
WEDNESDAY. THE PROBABILITY OF RA INCREASES TONIGHT AND CONTINUES
INTO WEDNESDAY AND WEDNESDAY EVENING. THERE IS ALSO A SLIGHT CHC
OF THUNDER WEDNESDAY AFTERNOON AND EVENING. A GUSTY SOUTHERLY WIND
IS LIKELY WEDNESDAY AFTERNOON AND EVENING AHEAD OF A COLD
FRONT...WHICH SWEEPS THROUGH THE REGION EARLY THU MORNING. DRIER
CONDITIONS SHOULD PREVAIL BY CHRISTMAS DAY ALONG WITH A GUSTY
WESTERLY WIND.

&&

.MARINE...
THE WEAK LOW PRESSURE AREA JUST OFF THE COAST CONTINUES TO KEEP
THE SEAS UP AROUND SCA LEVELS IN THE NORTHERN MARINE ZONES TONIGHT
WITH SEAS OF 5 TO 6 FT. SEAS HAVE BEEN SLOWLY DROPPING THERE AND
THEY SHOULD FALL BELOW 5 FT THIS EVENING. SO HAVE EXTENDED THE SCA
THERE THROUGH 10 PM FOR THE SEAS.

MEANWHILE...LOW PRESSURE ALONG THE NORTHERN GULF COAST HAS BEGUN
TO DEVELOP ALONG A STRONG COLD FRONT. THIS LOW WILL DEEPEN AND
LIFT NORTHWARD INTO THE OHIO VALLEY TONIGHT INTO WEDNESDAY. AHEAD
OF THE FRONT...A WARM FRONT WILL LIFT ACROSS THE WATERS. AHEAD OF
THE FRONT...EXPECT MORE LIGHT RAIN AND DRIZZLE TO DEVELOP
OVERNIGHT ALONG WITH REDUCED VISIBILITIES. A DENSE FOG ADVISORY
MAY BE NEEDED LATER TONIGHT BEFORE THE WARM FRONT PASSES THE REGION.

AS THE WARM FRONT CROSSES...THE WINDS WILL SHIFT FROM AN E-SE
DIRECTION TO A SW DIRECTION. AS THE LOW DEEPENS...THE PRESSURE
GRADIENT WILL TIGHTEN AND THE WINDS INCREASE TO 15 TO 20 ON THE
BAY AND 20 TO 25 KT IN THE COASTAL ZONE. THE FRONT WILL CROSS THE
AREA OVERNIGHT WED NIGHT AND SHIFT THE WINDS TO THE WEST. BUT THE
COLD ADVECTION BEHIND THE FRONT IS NOT STRONG SO EXPECT THAT THE
WINDS WILL DIMINISH ON CHRISTMAS DAY DURING THE AFTERNOON HOURS AS
HIGH PRESSURE BUILDS INTO THE AREA. SO HAVE RAISED SCA FLAGS FOR
WED AFTERNOON THROUGH THURSDAY AFTERNOON FOR THIS SYSTEM.

HIGH PRESSURE THEN BUILDS INTO THE REGION ON THURSDAY NIGHT AND
LINGERS THROUGH SATURDAY AS A STRONG UPPER LEVEL RIDGE BUILDS INTO
THE SOUTHEASTERN US AND KEEPS STRONG HIGH PRESSURE AT THE SURFACE
OVER THE REGION THROUGH SATURDAY. THE MODELS BEGIN TO STRUGGLE
WITH THE NEXT SYSTEM FOR SUNDAY AS A FRONT TRIES TO MOVE INTO THE
WATERS. FOR NOW EXPECT THE FRONT TO APPROACH FROM THE NORTH AND
THEN STALL A LOW PRESSURE LIFTS NORTHEASTWARD INTO THE REGION WITH
SHOWER AND LIGHT RAIN. THIS COULD AGAIN LIMIT VISIBILITIES...BUT
WINDS ARE NOT EXPECTED TO BE STRONG ENOUGH TO REACH SCA LEVELS.

&&

.CLIMATE...
RECORD HIGHS FOR CHRISTMAS EVE/WED 12/24:

RICHMOND.......71 F (1988)
NORFOLK........75 F (1891)
SALISBURY......67 F (1990)
ELIZ CITY NC...75 F (1990)

&&

.EQUIPMENT...
THE NOAA ALL HAZARDS RADIO SYSTEM AT WAKEFIELD VA HAS RETURNED TO
SERVICE.

&&

.AKQ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
NC...NONE.
VA...NONE.
MARINE...SMALL CRAFT ADVISORY FROM 1 PM WEDNESDAY TO 4 PM EST THURSDAY
     FOR ANZ630>634-650-652-654-656-658.
     SMALL CRAFT ADVISORY UNTIL 10 PM EST THIS EVENING FOR ANZ650-
     652.

&&

$$
SYNOPSIS...LKB
NEAR TERM...LKB
SHORT TERM...JDM/LKB
LONG TERM...ESS
AVIATION...AJZ/DAP
MARINE...ESS
CLIMATE...
EQUIPMENT...






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