-- Discussion containing changed information from previous version are highlighted. --
000
FXUS61 KAKQ 041218
AFDAKQ

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE WAKEFIELD VA
718 AM EST WED DEC 4 2013

.SYNOPSIS...
HIGH PRESSURE WILL LINGER OFF THE MID ATLANTIC COAST TODAY THROUGH
THURSDAY. MEANWHILE...A WARM FRONT LIFTS NORTH THROUGH THE REGION
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 THE WEEKEND.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
-- Changed Discussion --
SCATTERED LIGHT RAIN SHOWERS HAVE BECOME FOCUSED NEAR THE COAST
AND ARE EXPECTED TO TAPER OFF THROUGH LATE MORNING/EARLY AFTN.
TEMPERATURES WILL RUN ABOUT 5-7 DEGREES ABOVE NORMAL WITH READINGS
IN THE 60S AREAWIDE. ONSHORE WINDS AND LIGHT SHOWERS NEAR THE
IMMEDIATE CHESAPEAKE BAY AND ATLANTIC COASTS MAY HOLD TEMPS IN THE
UPPER 50S TODAY.
-- End Changed Discussion --

&&

.SHORT TERM /6 PM THIS EVENING THROUGH FRIDAY NIGHT/...
TONIGHT...
WAA REALLY KICKS INTO GEAR TONIGHT AS THE WARM FRONT LIFTS
NORTH AND PUTS THE AREA WITHIN THE WARM SECTOR. THE BEST MOISTURE
ASSOCIATED WITH THE WARM FRONTAL BOUNDARY WILL MOVE AWAY FROM THE
FA OVERNIGHT AND WILL RESULT IN A DRY FORECAST. A MILD NIGHT IS ON
TAP WITH LOWS IN THE LOW-MID 50S (UPPER 40S POSSIBLE MD EASTERN
SHORE).

THURSDAY THROUGH FRIDAY NIGHT...
A COLD FRONT CROSSES THE OH VALLEY ON THU AND GETS HUNG UP ALONG
THE SPINE OF THE APPALACHIANS THU NIGHT 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.
BECAUSE THE PROGRESSION OF THE FRONT HAS SLOWED ON THU...HAVE MADE
ADJUSTMENTS TWD A DRY FORECAST DURING THE DAY. HAVE MAINTAINED A
SCHC/CHC FOR PRECIP ALONG A LINE NORTH OF GENERALLY
FARMVILLE-RICHMOND-SALISBURY FOR THU NIGHT BUT SUSPECT THAT THIS
MAY NOT HAPPEN UNTIL CLOSER TO FRI MORNING...ESPECIALLY WITH
BREEZY SSW WINDS PRESENT ACROSS MOST OF THE AREA THU/THU NIGHT.
THE AFOREMENTIONED BREEZY CONDITIONS WILL ALSO HELP TO MIX WARMER
AIR ALOFT TO THE SFC AND RESULT IN HIGH TEMPERATURES IN THE UPPER
60S TO LOW/MID 70S...DESPITE MOSTLY CLOUDY SKIES.

AS THE COLD ARCTIC AIRMASS FINALLY TAKES OVER THE WARMER AIR TO
ITS SOUTH...THE FRONT WILL FINALLY START TO PUSH ACROSS THE AREA
FROM THE NORTHWEST BY FRI AFTN. SHARP TEMPERATURE AND PRESSURE
CONTRASTS BETWEEN THE WARMER AIRMASS OVER THE REGION VERSUS THE
COLD ARCTIC AIRMASS TO THE NORTHWEST WILL CAUSE SW WINDS TO BECOME
BREEZY WITH GUSTS UP TO 25 MPH DURING THE AFTN AND IN THE VICINITY
OF THE COLD FRONT. CONTINUED WAA ADVECTION AHEAD OF THE FRONT AND
FAVORABLE MIXING WILL ONCE AGAIN HELP TO BOOST HIGH TEMPS WELL
ABOVE NORMAL ON FRI...ESPECIALLY OVER SERN AREAS WHERE TEMPS
COULD REACH THE MID-UPPER 70S. FOR NW AREAS...TEMPS MAY ONLY BE
IN THE LOW-MID 60S DUE TO WHERE LOW CLOUDS AND PRECIP OCCUR. GIVEN
THE WELL-MIXED AND HIGHLY SHEARED ENVIRONMENT...THE CONVECTIVE
ENVIRONMENT WILL BE UNSTABLE ENOUGH TO SUPPORT THUNDERSTORMS FRI
INTO FRI EVENING. THERE MAY EVEN BE THE POTENTIAL FOR HAIL AND
STRONG THUNDERSTORM WINDS...BUT WILL ADDRESS THIS POSSIBLE IMPACT
IN MORE DETAIL ONCE THE FRONT GETS CLOSER TO THE REGION. THE COLD
FRONT CROSSES THE REST OF THE FA FRI NIGHT AND MOVES JUST OFF THE
COAST BY 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 LOWER 50S SE.

&&

.LONG TERM /SATURDAY THROUGH TUESDAY/...
-- Changed Discussion --
UNSETTLED AND COMPLEX WEATHER IS EXPECTED FROM SATURDAY THROUGH
TUESDAY. OVERALL...THE COLD FRONT MOVES OFF THE CAROLINA COAST
SAT MORNING AS A LONGWAVE RIDGE HOLDS STEADFAST OVER FLORIDA AND
THE CARIBBEAN. THIS WILL KEEP A PERSISTENT SW FLOW ALOFT ACROSS
THE REGION AND ALLOW A SERIES OF SHORTWAVES TO IMPACT THE AREA SUN
INTO EARLY NEXT WEEK.

FOR SATURDAY...PRECIPITATION WILL EVENTUALLY LINGER NEAR THE
MID ATLANTIC COAST AS THE COLD FRONT SAGS SWD THROUGH THE DAY.
HOWEVER THE FIRST OF SEVERAL POST-FRONTAL SHORTWAVES WILL MOVE
BACK INTO THE REGION FROM THE SW SAT NIGHT...SPREADING STEADY
RAINFALL BACK INTO THE AREA OVERNIGHT. NORTH WINDS WILL USHER
COLDER TEMPERATURES INTO THE REGION AND TEMPS ARE EXPECTED TO FALL
INTO THE 30S. PRECIP TYPE LATE SAT NIGHT/EARLY SUN MORNING WILL BE
HIGHLY DEPENDENT ON WHERE AND WHEN TEMPS DROP TO THE FREEZING
MARK. MOST AREAS OF THE CWA WILL EXPERIENCE RAIN WHILE THE COLDER
SPOTS OF THE PIEDMONT MAY SEE A MIX OF RAIN/FREEZING RAIN FOR A
PERIOD OF TIME. FAR NWRN AREAS SHOULD BE SLOW TO WARM SUN MORNING
AND ANY FREEZING RAIN THAT OCCURS SHOULD ALSO BE SLOW TO
TRANSITION BACK TO RAIN UNTIL LATER IN THE MORNING. HIGHS ON
SUN SHOULD RANGE FROM THE UPPER 30S NW TO MID 50S NEAR THE VA/NC
COAST. ANOTHER LOW PRESSURE DEEPENING OVER THE TN/OH VALLEYS ON
SUN/SUN NIGHT IS EXPECTED TO MODERATE THE AIRMASS DUE TO
WAA...FOLLOWED BY A COLD FRONTAL PASSAGE MON INTO TUE.
PRECIPITATION AT THIS TIME APPEARS TO BE ALL RAIN. TEMPERATURES ON
MON WARM INTO THE UPPER 40S FAR NW TO NEAR 60 SE.
-- End Changed Discussion --

&&

.AVIATION /12Z WEDNESDAY THROUGH SUNDAY/...
-- Changed Discussion --
MOISTURE ALONG/AHEAD OF AN APPROACHING WARM FRONT IS SPREADING
INCREASING MOISTURE INTO THE REGION EARLY THIS MORNING. LATER
TODAY...TOUGH CALL AS THERE IS CONFLICTING MODEL GUIDANCE AS TO
CIGS/VSBYS. IN GENERAL THINK ALL AREAS WILL SEE AT LEAST A FEW HRS
OF IFR CIGS DURING THE LATE MORNING/EARLY AFTN
TIMEFRAME...IMPROVING SLIGHTLY THROUGH THE AFTN...THEN WITH
DETERIORATING CONDITIONS TONIGHT/EARLY THU.

OUTLOOK...WARMER SSW FLOW WILL INCREASE TO 10-15 KT OR SO AND
SHOULD SCATTER OUT THE LOW CLOUDS THU. A COLD FRONT WILL BE SLOW
TO PROGRESS INTO THE AREA FRI/FRI NIGHT...HIGHEST CHANCES FOR
SIGNIFICANT REDUCTIONS IN CIGS/VSBYS LOOKS TO ARRIVE LATER FRI
NIGHT THROUGH SAT/SUN. GENLY APPEARS TO BE A RAIN EVENT FOR
KORF/KPHF/KECG/KSBY...WITH SOME POTENTIAL FOR MIXED PRECIP AT KRIC
SAT NIGHT/SUN.
-- End Changed Discussion --

&&

.MARINE...
RELATIVELY LIGHT S/SE FLOW TODAY AND TONIGHT WITH WIND SPEEDS
AVERAGING 10 KT OR LESS. AREA LOOKS TO BECOME WARM SECTORED
THU...AND WINDS WILL INCREASE FROM THE SSW. HOWEVER...WARM AIRMASS
WILL NOT MIX WELL OVER THE COLD WATERS...SO WINDS WILL PROBABLY BE
STRONGER/MORE GUSTY OVER LAND BY THU AFTN...ONLY AVERAGING 10-15 KT
ACRS THE WATERS. GRADIENT CONTINUES TO STRENGTHEN THU NIGHT/FRI
AHEAD OF A SLOW MOVING COLD FRONT. WILL STILL HAVE THE ISSUE OF
LIMITED MIXING THROUGH FRI...BUT COULD SEE MARGINAL SCA CONDITIONS
(MAINLY FOR SEAS) OVER THE NORTHERN COASTAL WATERS...AS WELL AS A
FEW GUSTS TO AROUND 20 KT FOR THE BAY AND SOUND.

A CONSENSUS BETWEEN THE MODELS WOULD BRING THE FRONT THROUGH THE
AREA LATER FRI NIGH/EARLY SAT MORNING. SCA CONDITIONS APPEAR LIKELY
FOR ALL ZONES BY SAT MORNING AS STRONG HIGH PRESSURE BUILDS TO THE
NORTH OF THE AREA AND MUCH COLDER AIR ALOFT BEGINS TO MIX DOWN OVER
THE WATERS. BOUNDARY STALLS TO THE SOUTH AS STRONG HIGH PRESSURE
BUILDS FROM THE GREAT LAKES TO NEW ENGLAND ON SUNDAY...WITH SCA
CONDITIONS STILL POSSIBLE.

&&

.AKQ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
NC...NONE.
VA...NONE.
MARINE...NONE.

&&

$$
SYNOPSIS...BMD
NEAR TERM...BMD
SHORT TERM...BMD
LONG TERM...LSA
AVIATION...LKB
MARINE...LKB