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000
FXUS61 KAKQ 120827
AFDAKQ

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE WAKEFIELD VA
327 AM EST THU DEC 12 2013

.SYNOPSIS...
CANADIAN HIGH PRESSURE BUILDS INTO THE REGION TODAY...THEN MOVES OFF
THE COAST TONIGHT AND FRIDAY. LOW PRESSURE FROM THE SOUTHWEST TRACKS
ACROSS THE REGION SATURDAY INTO EARLY SUNDAY.

&&

.NEAR TERM /TODAY/...
ARCTIC COLD FRONT QUICKLY MOVES OFF THE COAST THIS MORNING. 1040 MB
HIGH OVER THE NATIONS MID SECTION BUILDS EAST AND OVER THE AREA LATE.
GIVEN THE ORIGINS OF THIS AIRMASS...THE SNOW COVERAGE TO OUR WEST
AND FALLING DP TEMPS INTO THE SINGLE DIGITS...TEMPS MAY RUN A BIT
BELOW GUIDANCE. EXPECT A M SUNNY & COLD DAY. HIGHS IN THE L-M30S
NORTH TO 35-40 SOUTH. CAA KEEPS EASTERN AREAS ON THE BREEZY SIDE
(NW 15-25 MPH).

&&

.SHORT TERM /TONIGHT THROUGH SATURDAY NIGHT/...
SFC HIGH PRESSURE MOVES ACROSS THE CAROLINAS TONIGHT WITH THE RIDGE
AXIS OVERHEAD FRIDAY MORNING BEFORE SHIFTING OFFSHORE FRIDAY AFTRN.
EXPECT A CLEAR & COLD NIGHT WITH DECOUPLING WINDS. EXCELLENT
RADIATIONAL COOLING CONDITIONS ALLOWS TEMPS TO DROP INTO THE UPPER
TEENS TO L20S. SUNNY TO START FRIDAY WITH SOME HIGH LEVEL CLOUDS
DURING THE AFTERNOON. RETURN SW FLOW ALLOWS H85 TEMPS TO RISE A
BIT. HIGHS IN THE M-U40S EXCEPT L-M40S ACROSS THE DELMARVA.

NEXT IN THE SERIES OF CANADIAN HIGH PRESSURE SYSTEMS DROPS SOUTHEAST
FRIDAY AND SATURDAY. THE LEADING COLD FRONT PROGGED TO STALL ACROSS
THE NORTHERN STATES AS IT ENCOUNTERS THE HIGH PRESSURE TO THE SOUTH.
MEANWHILE...SOUTHERN STREAM JET BECOMES ACTIVE AS S/W ENERGY DIVES
SOUTH FROM THE NATIONS MID SECTION AND SPAWNS CYCLOGENSIS ACROSS THE
DEEP SOUTH FRIDAY NIGHT...LIFTING NE ACROSS THE MID ATLANTIC REGION
SATURDAY. THIS COMPLEX SYSTEM CONJEALS INTO A MILLER B STORM AS IT
LIFTS NORTHEAST AND OFF THE NEW ENGLAND COAST SATURDAY NIGHT.

MODELS IN GENERAL AGREEMENT WITH THE EVOLUTION OF THIS SYSTEM BUT
DIFFER WRT TIMING AND MOISTURE FIELDS. LEANED TOWARD A SREF SOLN
WHICH SEEMS TO BE A MODEL COMPROMISE ATTM.

CLOUDS INCREASE FRI NIGHT WITH SOME LIGHT PCPN POSSIBLE AFTER 09Z
NWRN MOST COUNTIES. P-TYPE A CONCERN GIVEN TEMPS AROUND FREEZING.
GIVEN THE INITIAL TEMP/DP SPREAD & CRITICAL THICKNESSES...EXPECT
SOME LIGHT MIXED PCPN (FZ RAIN/IP) FOR A FEW HOURS AT ONSET ALONG
AND NW OF A LKU-FVX LINE. QPF WITH THIS QUITE MINIMAL (A FEW
HUNDREDTHS AT BEST)...HOWEVER ANY ICE COULD POTENTIALLY BECOME AN
ISSUE SO WILL INCLUDE A SHORT BLURB IN THE HWO. LOWS U20S-L30S.

HIGH PRESSURE OVER EASTERN CANADA WILL BE PROGRESSIVE...THUS NOT
STRONG ENOUGH TO HOLD THE CAD WEDGE IN VERY LONG EAST OF MTS. UPSHOT
WILL BE JUST ENOUGH OF AN EROSION TO CHANGE ALL PCPN TO LIQUID BY
NOON SAT. MODELS NOW SHOWING DECENT LIFT/OMEGA FOR ANOTHER WIDESPREAD
RAIN ACROSS THE REGION SATURDAY AFTERNOON AND EVENING. THUS...BUMPED
POPS UP TO NEAR 100%. LOW WEST OF MTS FILLS WHILE A SECOND DOMINATE
COASTAL LOW FORMS OVER EASTERN NC THEN TRACKS NE OFF THE DELMARVA
COAST SAT NIGHT. TEMPS TRICKY SAT AND WILL BE BASED ON THE LOW TRACK
NEAR THE COAST. HIGHS U30-L40S NWRN MOST COUNTIES RANGING TO BTWN
55-60 SERN COASTAL AREAS. TRAILING COLD FRONT CROSSES AREA SAT LATE
NIGHT TAPERING PCPN OFF ACROSS WESTERN COUNTIES LATE. EXPECT MOST
PCPN TO END BEFORE ENOUGH COLD AIR COMES IN BUT NOT OUT OF THE
QUESTION THAT NWRN MOST COUNTIES SEES A FEW WET SNOW FLAKES BEFORE
PCPN ENDS. LOWS SAT NIGHT IN THE L-M 30S NW TO L-M40S SE.

&&

.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
SFC COLD FRONT PUSHES OFF THE MID ATLANTIC COAST SUNDAY MORNING.
GFS QUICKER TO DRY IT OUT WITH ECMWF LINGERING MOISTURE ACROSS SERN
SECTIONS THROUGH 18Z. KEPT CHC POPS IN AREAS E OF I95 DURING THE
MORNING. DRYING EXPECTED ALL AREAS SUNDAY AFTERNOON.

DRY WX RETURNS TO START NEXT WEEK. HIGHS SUN IN THE 40S-L50S. COOLER
MON WITH HIGHS IN THE 30S-L40S. HIGHS TUE/WED IN THE 40S-L50S.

&&

.AVIATION /08Z THURSDAY THROUGH MONDAY/...
COLD FRONT EXTENDING ALONG THE LEE SIDE OF THE APPALACHIANS WILL
CROSS THE LOCAL AREA EARLY THIS MORNING (THURS MORNING). FRONTAL
PASSAGE WILL ONLY BE NOTED BY INCREASING NW WINDS. IDEAL
RADIATIONAL COOLING OCCURRING OVER THE REGION THIS MORNING...BUT
DEWPOINTS IN THE LOW-MID 20S AND THE FRONTAL PASSAGE WILL INHIBIT
ANY FOG THIS MORNING. THE STRONGEST GRADIENT WINDS WILL OCCUR THIS
MORNING...WITH OCCASIONAL GUSTS OF 20-25 KT NEAR THE COAST (ESP
KORF AND KSBY). SOME SPEED SHEAR WILL EXIST THIS MORNING AS WINDS
1-2K FT AGL INCREASE TO 20-25 KT WITH LIGHTER WINDS AT THE SFC.
ONCE MIXING INCREASES THIS MORNING...ANY SPEED SHEAR CONCERNS
WILL BE NEGATED. WILL MONITOR BUT WILL KEEP OUT OF TAFS ATTM. HIGH
PRESSURE WILL BEGIN TO BUILD BACK OVER THE MID-ATLANTIC REGION
THIS AFTERNOON- TONIGHT. THE GRADIENT WILL BEGIN TO RELAX OVER
INTERIOR VA/NC THIS AFTERNOON AND ALONG THE COAST LATE TODAY-
EARLY TONIGHT. MODEST MID-LEVEL MOISTURE AND STEEP LOW LEVEL LAPSE
RATES WILL LIKELY PRODUCE FEW-SCT FAIR WEATHER CU WITH DECKS 3-6K
FT AGL THIS AFTERNOON DURING PEAK HEATING.

OUTLOOK...DRY/VFR CONDITIONS FRIDAY AS HIGH PRESSURE BUILDS
OVERHEAD...SLIDING OFFSHORE FRIDAY NIGHT. LOW PRESSURE WILL LIFT
FROM THE SE STATES INTO THE MID-ATLANTIC LATE SAT-SAT
NIGHT...SPREADING PRECIP INTO THE REGION AS EARLY AS SATURDAY
MORNING. PRECIP WILL EXIT THE COAST LATE SUNDAY. LOWER CIGS AND
VSBYS ARE LIKELY WITH POSSIBLE FROZEN PRECIP OVER THE ERN VA
PIEDMONT EARLY SAT.

&&

.MARINE...
AS OF 3AM EST...COLD FRONT WAS LOCATED JUST WEST OF THE WATERS OVER
CNTRL VA. BEGINNING TO SEE INCREASING W-NW WINDS OVER THE WATERS
EARLY THIS MORNING WITH GUSTS OF 18 KT OVER THE WATERS. UPSTREAM
PROFILERS INDICATE WINDS A FEW THOUSAND FT ALOFT ARE INCREASING TO
25-30 KT...WHICH LINES UP WELL WITH CURRENT MODELS. STRONGEST CAA
WILL ARRIVE BEHIND THE FRONT WITH THE LATEST HI-RES MODELS SHOWING A
RAPID INCREASE IN NW WINDS (15-25 KT OVER THE BAY AND 20-25 KT OVER
THE COASTAL WATERS) BTWN 4-6AM THIS MORNING. GRADIENT AND CAA WILL
CONTINUE THRU THE DAY WITH SCA HEADLINES REMAINING IN PLACE THROUGH
6PM. LOCAL STUDIES SUGGEST SEAS WILL BUILD TO 5-6 FT 20 NM OUT
MID-LATE MORNING THRU THE AFTERNOON...SO HAVE INCREASED SEAS TO 3-5
FT. WAVES WILL REMAIN GENERALLY 2-3 FT. HIGH PRESSURE WILL BEGIN TO
NOSE IN FROM THE WEST LATE TODAY...ALLOWING THE GRADIENT TO RELAX
AND CAA TO WANE. HIGH PRESSURE WILL CONTINUE TO BUILD OVER THE WATER
TONIGHT INTO FRIDAY WITH SUB SCA CONDITIONS PREVAILING. UNSETTLED
CONDITIONS RETURN THIS WEEKEND AS LOW PRESSURE LIFTS OVER THE
REGION. MODELS DIFFER WITH THE EXACT TRACK OF THE LOW...BUT HAVE
TRENDED THE CURRENT FORECAST TOWARD THE GFS AS THE NAM SEEMS TO BE
TOO FAR INLAND WITH THE LOW. THE DIFFERENCES OVER THE WATERS ARE
QUITE DRASTIC AS THE NAM HAS 925MB WINDS OVER 50 KT SAT NIGHT WHILE
THE GFS HAS 925MB WINDS OF 20-25 KT. REGARDLESS...STRONG INVERSION
WILL PREVENT WINDS FROM MIXING TO THE WATER...SO WILL KEEP SPEEDS
UNDER 15 KT ATTM. SEAS WILL LIKELY BUILD TO 4-5 FT 20 NM OUT
SAT-SUN.

&&

.AKQ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
NC...NONE.
VA...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 6 PM EST THIS EVENING FOR
     ANZ630>632-634>638-650-652-654.
     SMALL CRAFT ADVISORY UNTIL 6 PM EST THIS EVENING FOR ANZ633-
     656-658.

&&

$$
SYNOPSIS...MPR
NEAR TERM...MPR
SHORT TERM...MPR
LONG TERM...JDM/MPR
AVIATION...SAM
MARINE...SAM