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-- Discussion containing changed information from previous version are highlighted. --
000
FXUS61 KAKQ 052124
AFDAKQ

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE WAKEFIELD VA
424 PM EST THU DEC 5 2013

.SYNOPSIS...
HIGH PRESSURE REMAINS OFF THE COAST THROUGH TONIGHT. A SLOW
MOVING COLD FRONT IS EXPECTED TO MOVE INTO THE AREA BY MID DAY
FRIDAY...FOLLOWED BY A PERIOD OF UNSETTLED WEATHER THROUGH EARLY
NEXT WEEK.

&&

.NEAR TERM /UNTIL 6 AM FRIDAY MORNING/...
MILD S-SW FLOW CONTINUES ACROSS THE REGION INTO TONIGHT...WITH SFC
HIGH PRESSURE SITUATED OFF THE COAST. ABUNDANT LOW-LEVEL MOISTURE
IN PLACE TONIGHT (DEW PTS IN THE 50S TO AROUND 60) WILL ALLOW
CLOUDS TO REMAIN PLENTIFUL...WITH PATCHY DENSE FOG POSSIBLE AGAIN
ESPECIALLY ALONG THE COAST AND OVER THE WATERS. LATEST RADAR
COMPOSITE SHOWS A BATCH OF SHOWERS MOVING EAST AND OFF THE LOWER
MD EASTERN SHORE. MEANWHILE...ANOTHER BATCH OF SHOWERS IS PUSHING
EAST ACROSS SOUTHERN VA AND NE NC. THESE SHOWERS WILL CONTINUE TO
MOVE EAST THROUGH THE EVENING HOURS AND WILL CARRY CHC POPS
(30-40%) DURING THIS TIME. A COLD FRONT WILL CONTINUE TO MOVE
EASTWARD FROM THE OHIO VALLEY AND GETS HUNG UP ALONG THE SPINE OF
THE APPALACHIANS LATE TONIGHT INTO FRI MORNING. THIS IS DUE TO A
BLOCKING PATTERN DEVELOPING...WHERE A STRONG ARCTIC HIGH IS
DIGGING INTO THE NCTRL U.S. AND ANOTHER HIGH IN THE WRN ATLANTIC
IS PREVENTING THE COLD FRONT FROM PROGRESSING EWD. ONCE ANY LIGHT
SHOWERS END THIS EVENING...A DRY PERIOD IS ANTICIPATED OVERNIGHT.
MOISTURE AND WEAK SHORTWAVE ENERGY THEN RIDES ALONG THE FRONT FROM
SW TO NE AND MAY BRING PCPN BACK INTO FAR NW PORTIONS OF THE FA
TOWARD DAYBREAK. MILD TONIGHT WITH LOWS IN THE UPR 50S TO LOW 60S.

&&

.SHORT TERM /6 AM FRIDAY MORNING THROUGH SUNDAY/...
-- Changed Discussion --
THE COLD FRONT TO THE NORTHWEST WILL EVENTUALLY START TO SAG
SOUTHWARD BY FRIDAY AFTERNOON. AHEAD OF THE BOUNDARY...SW FLOW
WILL ALLOW MILD AND DRY CONDITIONS TO CONTINUE. ALONG AND NORTH
OF THE BOUNDARY...AM EXPECTING STEADIER PCPN TO ARRIVE ACROSS
NORTHERN AREAS...ESPECIALLY IN THE AFTERNOON. AS FAR AS POPS
GO...HAVE LIKELY POPS (60%) SPREADING SOUTHWARD TO ALONG A
FLUVANNA TO HANOVER TO DORCHESTER MD LINE BY LATE FRIDAY
AFTERNOON. FARTHER SOUTH...WILL KEEP THE FORECAST DRY MAINLY ALONG
AND SOUTH OF VA HWY 58. CONTINUED WAA ADVECTION SOUTH OF THE FRONT
AND FAVORABLE MIXING WILL HELP BOOST HIGH TEMPS WELL ABOVE NORMAL
ON FRI...ESPECIALLY OVER SRN AREAS WHERE TEMPS SHOULD REACH THE
MID-UPPER 70S. RECORDS ARE NOT EXPECTED TO BE BROKEN (SEE CLIMATE
SECTION BELOW). FOR NW AREAS...TEMPS MAY ONLY BE IN THE LOW-MID
60S DEPENDING ON WHERE LOW CLOUDS AND PRECIP OCCUR. THE COLD FRONT
SWEEPS THROUGH THE REST OF THE FA FRI NIGHT AND MOVES SOUTH OF THE
AREA SAT MORNING. PRECIPITATION IS EXPECTED TO BECOME MORE
WIDESPREAD AND STEADY OVERNIGHT FRI. LOW TEMPS WILL BE TRICKY
DEPENDING ON HOW FAST THE POST-FRONTAL ARCTIC AIR CAN MOVE INTO
THE REGION AND WHEN WINDS TURN TO THE NORTHWEST/NORTH. AM
CURRENTLY ANTICIPATING A CONTRAST WITH LOWS IN THE UPPER 30S/LOWER
40S NW TO LOW/MID 50S FAR SE.

SATURDAY...
THE AFOREMENTIONED COLD FRONT STALLS OUT ACROSS THE SERN U.S. AS
ARCTIC HIGH PRESSURE EXPANDS EWD FROM THE OHIO VALLEY AND INTO THE
NORTHEAST. N-NE SFC WINDS WILL CONTINUE TO FUNNEL COLDER AIR INTO
THE MID ATLANTIC REGION THROUGH SAT WITH HIGHS EITHER HOLDING
STEADY OR ONLY RISING A COUPLE OF DEGREES FROM THEIR MORNING LOWS.
HIGHS AROUND 40 NW TO THE LOW/MID 50S FAR SE. THE QUESTION THAT
STILL REMAINS IS JUST HOW MUCH PRECIP LINGERS ACROSS THE LOCAL
AREA ON SATURDAY. ATTM...THE ECMWF AND GFS MODELS STILL FAVOR
LIGHT RAIN LINGERING ALONG AND SOUTH OF A FARMVILLE-RICHMOND-
SALISBURY LINE IN THE MORNING...THEN SHIFTING INTO JUST FAR
SOUTHERN VA AND NE NC IN THE AFTERNOON. THE NAM/SREF SOLUTIONS NOT
ONLY DRIVE THE SFC COLD FRONT A LITTLE FARTHER SOUTH BUT THEY
FLATTEN THE FRONT INTO A MORE WEST TO EAST ORIENTATION...WHICH
SUPPORTS LESS PRECIPITATION SAT AFTN. CONTINUE TO FAVOR THE PRECIP
GETTING HUNG UP NEAR SE COASTAL AREAS AND BEING SLOWER TO EXIT THE
REGION CONSIDERING THE GIVEN POSITION/STRENGTH OF THE WRN ATLANTIC
RIDGE. WILL KEEP BEST PRECIP CHANCES ACROSS THE SERN HALF OF THE
FA THROUGHOUT THE DAY.

SATURDAY NIGHT...
MODELS ARE IN GENERAL AGREEMENT WITH LAYING THE FRONTAL BOUNDARY
INTO A MORE FLAT W-E ORIENTATION SAT NIGHT...THEN PULLING IT BACK
UP THE APPALACHIANS ALMOST LIKE A RETROGRADING LEE TROUGH.
SHORTWAVE ENERGY MOVING UP THIS BOUNDARY FROM THE TN VALLEY IS
EXPECTED TO ENHANCE AND SPREAD PRECIPITATION BACK INTO THE REGION
FROM THE SOUTH/SOUTHWEST OVERNIGHT. MEANWHILE...A COLD AIR WEDGE IS
BEGINNING TO TAKE FORM AS COLD ARCTIC AIR FILTERS INTO THE REGION
FROM THE N/NE. THE COMBINATION OF WARMER AIR IN THE SOUTHEAST
VERSUS THE COLDER AIR TO THE NORTH WILL MAKE FOR A TRICKY
PRECIP-TYPE FORECAST. MODEL DISCREPANCIES REGARDING PRECIP
PLACEMENT AND TIMING ARE DIFFERENT ENOUGH TO MAKE IT DIFFICULT TO
DETERMINE WHERE RAINFALL WILL TRANSITION TO SLEET AND/OR FREEZING
RAIN. AT THIS TIME...THE GFS/ECMWF ARE THE MOST PROGRESSIVE IN
PUSHING THE PRECIP NWD OVERNIGHT. THE NAM HAS MORE OF A DRY LOOK
TO IT...NOT BRINGING PRECIP BACK INTO SW PORTIONS OF THE FA UNTIL
AROUND 12Z SUN. THIS DELAY IS ALSO RESULTING IN A COLDER
TEMPERATURE BIAS OVER NWRN AREAS. THE SREF SPLITS THE DIFFERENCE
BTWN THE FAST GFS/ECMWF AND THE SLOWER/COLDER NAM. USING THICKNESS
HEIGHTS AND WET BULB ZERO TEMPS TO DETERMINE A GENERAL P-TYPE...
HAVE INTRODUCED SOME FREEZING RAIN AND SLEET INTO NW PORTIONS OF
THE FA EARLY SUNDAY MORNING. A MIX OF RAIN AND FREEZING RAIN WILL
BE POSSIBLE EAST OF I-95 FROM EMPORIA TO NEW KENT COUNTY INTO THE
NORTHERN NECK DURING THIS TIME. FARTHER EAST...ALL RAIN IS
EXPECTED SATURDAY NIGHT...WITH THE LOWER MD EASTERN SHORE PROBABLY
REAMINING FREE OF PRECIP UNTIL AFTER 12Z SAT. LOW TEMPS ARE
EXPECTED TO BE BELOW FREEZING WEST OF A LINE FROM EMPORIA TO NEW
KENT TO THE INTERIOR LOWER MD EASTER SHORE...AND IN THE MID 30S TO
NEAR 40 SOUTH AND EAST AND SE OF THIS LINE.

SUNDAY...
THE CHALLENGING FORECAST CONTINUES INTO SUNDAY WHEN OVERRUNNING
PRECIP CONTINUES TO OVERSPREAD THE COLD NEAR-SURFACE AIR. MODEL
CONSENSUS FOR SUNDAY SHOWS A LITTLE BIT COLDER TEMPS THAN WHAT HAS
BEEN PREVIOUSLY EXPECTED WITHIN THE CAD SETUP...ESPECIALLY THE NAM
AND GFS. THE COLDER TREND MEANS THERE IS A POSSIBILITY FOR FROZEN
PRECIP TO HOLD ON LONGER ALONG/WEST OF THE I-95 CORRIDOR...AND
THEREFORE SUGGESTING A HIGHER POSSIBILITY OF WINTER WX HEADLINES
BEING NECESSARY ACROSS THE AREA. IF THE ATMOSPHERE DOES IN FACT
START OUT COLDER...THEN THERE COULD BE MORE SNOW/SLEET THAN FIRST
THOUGHT ACROSS THE NW AS WELL BEFORE A CHANGEOVER TO FREEZING
RAIN. BECAUSE OF THE UNCERTAINTIES WITH P-TYPES AND DURATION OF
FROZEN PRECIP...WILL NOT GET TOO SPECIFIC WITH THE FORECAST JUST
YET. HAVE CONTINUED THE TREND OF SHOWING THE POSSIBILITY OF FROZEN
PRECIP ON SUNDAY...ESPECIALLY THROUGH EARLY AFTERNOON...ALONG AND
NORTH OF A LUNENBURG TO TRI-CITIES TO NORTHERN NECK TO SALISBURY
LINE. HIGHS SUNDAY WILL RANGE FROM THE LOW/MID 30S WEST TO THE LOW
50S ALONG THE SE COAST.
-- End Changed Discussion --

&&

.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
DUE TO THE 12Z MODELS COLDER AND SLOWER WITH ONSET OF THE EVENT
SUNDAY...BUFKIT DATA NOW SUPPORTS A CONTINUATION OF P-TYPE ISSUES
ACROSS NWRN MOST COUNTYS THROUGH SUNDAY EVENING AS THE WEDGE WILL
BE LOCKED IN PLACE. SO WILL CONTINUE THE FZ RAIN FOR LOUISA/
FLUVANNA/WESTERN GOOCHLAND AND WESTERN CAROLINA COUNTY THROUGH
MIDNIGHT. OTW...RAIN CONTINUES ACROSS THE FA WITH STEADY TEMPS
MOST OF THE NIGHT...SLOWLY RISING AFTER 08Z AS A WEAK WAVE OF LOW
PRESSURE PULLS SOME OCEANIC AIR INLAND.

FIRST WAVE OF LOW PRESSURE MOVES NE OF FA MON MORNING WITH MODELS
INDICATING A SERIES OF WEAK WAVES MOVING NE AHEAD OF THE NEXT COLD
FRONT THAT WILL CROSS THE REGION LATE MONDAY AFTERNOON AND NIGHT.
ENOUGH MOISTURE PROGGED TO CONTINUE THE RAIN CHCS ACROSS THE AREA
MON. MUCH MILDER AS THE FLOW BECOMES SW BUT THE COLD FRONTAL PASSAGE
RESULTS IN ANOTHER TRICKY TEMP FORECAST. EXPECT A WIDE RANGE IN
TEMPS AS RESIDUAL WEDGING LEADS TO TEMPS HOLDING AROUND 50 NORTHERN
MOST COUNTYS...WITH MUCH MILDER AIR (AND MAYBE SOME PARTIAL SUN)
RESULTING IN TEMPS WARMING INTO THE 60S AND POSSIBLY NEAR 70 IVOF
ALBEMARLE SOUND.

SAID COLD FRONT SLOWS ITS SOUTHERLY MOVEMENT MON NITE AND TUESDAY AS
YET ANOTHER IN A SERIES OF S/W RIDES NE ALONG THE BOUNDARY. THIS
SCENARIO WILL LIKELY KEEP THE PCPN CHCS GOING INTO TUESDAY. ONE
CAVEAT TO THE FORECAST IS THE COLDER AIR COMING IN FROM THE NORTH
LATE MONDAY NIGHT. AS TEMPS FALL TO NEAR FREEZING...CRITICAL
THICKNESSES SUPPORTS SOME WET SNOW FLAKES MIXING IN WITH THE RAIN
ACROSS NORTHERN MOST COUNTYS...SO HAVE INTRODUCED A RAIN/SNOW MIX
LATE MON NIGHT FROM LKU-SBY. RAIN ELSEWHERE WITH LOWS IN THE
M30S-M40S. FRONT SLOWLY MOVES OFF THE CAROLINA COAST LATE TUESDAY
WITH CAA SETTING IN. STILL A CHC FOR RAIN WITH HIGHS FROM 40 NORTH
TO M50S SOUTH.

NEXT CANADIAN HIGH PRESSURE BUILDS INTO THE AREA WED AND THURS.
THE GFS SHOWS ANOTHER WAVE OF LOW PRESSURE PROGGED TO DEVELOP ALONG
THE STALLED FRONTAL BOUNDARY ACROSS SERN STATES BY MID WEEK WITH
MOISTURE FROM THIS SYSTEM STAYING JUST SOUTH OF AKQ FA. THE 12Z
ECMWF PUSHES THE COASTAL SYSTEM FURTHER OFFSHORE WITH HIGH PRESSURE
DOMINATING THE ENTIRE REGION. WILL TREND THE DAY 6 AND 7 FORECAST AS
DRY AND COLDER. HIGHS BOTH DAYS IN THE M30S-M40S. LOWS 20-30.

&&

.AVIATION /21Z THURSDAY THROUGH TUESDAY/...
STILL SOME IFR EARLY THIS AFTERNOON MAINLY NEAR KRIC. LOOKING AT
THE RAP AND NAM WOULD EXPECT MOST AREAS TO LIFT TO MVFR OR VFR
CEILINGS DURING THE AFTERNOON. THERE IS A WEAK SHORTWAVE CROSSING
THE AREA WHICH MAY BRING SOME SHOWERS TO SBY. OVERNIGHT TONIGHT
WINDS KEEP UP AROUND 10 KTS SO EVEN WITH VERY MOIST AIR BELIEVE IT
WILL BE MAINLY STRATUS THAT FORMS. BROUGHT ALL SITES BACK DOWN TO
IFR CEILINGS BUT HELD MOST VSBYS IN THE MVFR RANGE. STILL IN THE
HUMID AIR MASS ON FRIDAY BUT WITH AN APPROACHING FRONT SHOULD GET
CLOUDS BACK TO VFR RANGE BY LATE MORNING AT ALL LOCATIONS.

FRONT PUSHES THROUGH THE AREA FRIDAY NIGHT INTO SATURDAY WITH
PLENTY OF RAIN AND WIDESPREAD IFR CONDITIONS BEHIND THE FRONT. BY
SATURDAY NIGHT EXPECT SOME CLEARING WITH VFR CONDITIONS RETURNING.
NEXT WAVE OF LOW PRESSURE WILL MOVE BY ON SUNDAY WITH MORE
WIDESPREAD IFR CONDITIONS AND WITH A GREATER PROBABILITY FOR MIXED
PRECIP AT KRIC SUNDAY.

&&

.MARINE...
WARM FRONT HAS LIFTED N OF THE AREA TODAY WITH A S FLOW ACROSS THE
WATERS. WINDS PROGGED TO REMAIN BLO SCA LEVELS THROUGH FRI...HOWEVER
WNA SUGGESTS SEAS OUT NEAR 20 NM FLURT WITH 5 FT FRI. GIVEN WNA
SEEMS TO RUN HIGH IN A S FLOW...CONFIDENCE NOT HIGH ENOUGH TO PUT
OUT A MARGINAL SCA FOR SEAS OUT NEAR 20 NM SO NO HEADLINES EXPECTED
IN SHORT TERM.

MODELS CONTINUE TO ADVERTISE A STRONG CAA SURGE BEHIND A COLD FRONT
LATE FRI NIGHT AND SATURDAY. DESPITE THIS BEING A LATE 3RD / 4TH
PERIOD EVENT...CONFIDENCE HIGH ENOUGH TO HOIST SCA HEADLINES FOR THE
CHES BAY / LOWER JAMES RIVER / COASTAL WATERS LATE FRI NIGHT AND
SAT. WENT WITH A 00Z STARTING TIME FOR THE CURRITUCK SOUND AS THE
FLOW AROUND A WAVE OF LOW PRESSURE INCREASES THE GRADIENT ACROSS NC.
SEAS 4-5 FT ALL AREAS BY SAT...THEN 5-6 FT THEREAFTER. HELD OFF ON
ANY HEADLINES FOR THE REST OF THE RIVERS AS THAT SEEMS TO BE A 4TH
PERIOD HEADLINE.

SCA`S WILL LIKELY BE NEEDED THROUGH THE WEEKEND...ESPECIALLY ACROSS
THE COASTAL AREAS AS A PERSISTANT NE FLOW WILL KEEP SEAS AOA 5 FT
INTO EARLY NEXT WEEK.

&&

.TIDES/COASTAL FLOODING...
-- Changed Discussion --
GIVEN THE ASTRONOMICAL TIMING OF THE EVENT...PREDICTED TIDES AND
LEVELS ARE PROGGED TO REMAIN BLO ANY CRITICAL THRESHOLDS THROUGH THE
WEEKEND.
-- End Changed Discussion --

&&

.CLIMATE...
-- Changed Discussion --
RECORD HIGH TEMPERATURES FRIDAY (12/6)...
RIC 81 IN 1998
ORF 79 IN 1998
SBY 77 IN 1998
ECG 80 IN 1998
-- End Changed Discussion --

&&

.AKQ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
NC...NONE.
VA...NONE.
MARINE...SMALL CRAFT ADVISORY FROM 1 AM TO 4 PM EST SATURDAY FOR
     ANZ630>632-634-650-652.
     SMALL CRAFT ADVISORY FROM 7 PM FRIDAY TO 4 PM EST SATURDAY FOR
     ANZ633.
     SMALL CRAFT ADVISORY FROM 5 AM TO 4 PM EST SATURDAY FOR ANZ638-
     654-656-658.

&&

$$
SYNOPSIS...JDM
NEAR TERM...JDM
SHORT TERM...BMD/JDM
LONG TERM...MPR
AVIATION...LKB/JAB
MARINE...MPR
TIDES/COASTAL FLOODING...MPR
CLIMATE...AKQ