-- Discussion containing changed information from previous version are highlighted. --
000
FXUS62 KILM 092128
AFDILM

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE WILMINGTON NC
428 PM EST MON DEC 9 2013

.SYNOPSIS...
SOUTHERLY WINDS WILL BRING WARM WEATHER...CLOUDS AND GREATER
CHANCES OF RAIN AHEAD OF AN APPROACHING COLD FRONT TONIGHT INTO
TUESDAY. A COLD FRONT WILL MOVE THROUGH LATE TUESDAY WITH COOLER
AND DRIER HIGH PRESSURE MOVING IN MID WEEK AND PERSISTING THROUGH
THE END OF THE WORK WEEK. A COLD FRONT WILL BRING ANOTHER CHANCE
OF RAIN FOR THE WEEKEND.

&&

.NEAR TERM /UNTIL 6 AM TUESDAY MORNING/...
-- Changed Discussion --
AS OF 300 PM MONDAY...THE COOL WEDGE OF HIGH PRESSURE WAS HOLDING
ON TIGHT INLAND. TEMPERATURE SPREAD CLOSE TO 30 DEGREES OVER THE
FORECAST AREA THIS AFTN. SKIES BRIGHTENED ACROSS THE COASTAL ZONES
ENOUGH TO ALLOW TEMPS TO RISE INTO THE 70S WHILE CLOUDY INLAND
AREAS REMAINED IN CLOSER TO 50.

COLD FRONT WILL APPROACH FROM THE WEST THROUGH TONIGHT AS COASTAL
FRONT PROGRESSES NORTH AND INLAND ERODING THE WEDGE AND PRODUCING
A WARMER SOUTHERLY FLOW. STRONGER SOUTHERLY WINDS ALOFT WERE ABLE
TO MIX DOWN AS INVERSION BROKE AND DEEPER MIXING OCCURRED ALONG
THE COAST. INLAND AREAS DID NOT TAP INTO WARMER AIR ALOFT AS
INVERSION HELD STRONG WITH COOL POOL AT SURFACE. THEREFORE LOW
CLOUDS AND FOG HELD ON INLAND WHILE SKIES CLEARED ALONG THE COAST.

AS WARM FRONT PROGRESSES INLAND AND NORTH THE COOL WEDGE WILL
CONTINUE TO SLOWLY ERODE THROUGH TONIGHT. MODELS SHOWING WINDS
ALOFT DIMINISHING THROUGH THIS EVENING BEFORE INCREASING AGAIN
AFTER MIDNIGHT. MAY SEE ANOTHER ROUND OF FOG DEVELOP CLOSER TO THE
COAST.

A PERTURBATION IN THE SW MID TO UPPER LEVEL FLOW ALOFT MAY HELP
TO ENHANCE THE UPWARD MOTION AND MODELS SHOWING AREA OF LOW
PRESSURE PROGRESSING ALONG WARM FRONTAL BOUNDARY WHICH SHOULD HELP TO
PRODUCE GREATER CHC OF SOME MEASURABLE PCP INLAND AND NORTHEST OF
AREA. WILL KEEP POPS OUT OF COASTAL AREAS THIS EVENING BUT MAY
SEE FOG AND DRIZZLE AGAIN BEFORE WINDS PICK UP AFTER MIDNIGHT AS
GRADIENT TIGHTENS AS COLD FRONT MOVES EAST AND LOW DEVELOPS.

COASTAL AREAS MAY DROP OUT AS SKIES REMAIN LESS CLOUDY HEADING
INTO THE EVENING WHILE INLAND TEMPS WILL REMAIN MORE MODERATED BUT
MUCH COOLER TO BEGIN WITH. EXPECT SOUTHERLY WINDS TO DROP OFF BUT
STILL REMAIN HIGH ENOUGH TO PREVENT MORE IDEAL RADIATIONAL COOLING
CONDITIONS AND KEEP WAA THROUGH TONIGHT. OVERALL WILL BE RUNNING
WELL ABOVE NORMAL WITH MID 50S MOST LOCATIONS AND CLOSE TO 60
RIGHT ALONG THE COAST.
-- End Changed Discussion --

&&

.SHORT TERM /6 AM TUESDAY MORNING THROUGH TUESDAY NIGHT/...
AS OF 300 PM MONDAY...COLD FRONT AND FLAT WAVE OF LOW PRESSURE WILL BE
ENTERING FAR NWRN ZONES AN HOUR OR TWO AFTER THE START OF THE
PERIOD. NOT SURE HOW MUCH SHOWER ACTIVITY WILL MANAGE TO PRECEDE THE
BOUNDARY SINCE THE MID LEVELS DO NOT SEEM TO MOISTEN UP MUCH UNTIL
ITS IMMEDIATE ARRIVAL. SO FCST SHOWS HIGHEST RAIN CHANCES OVER NWRN
ZONES EARLY TRANSFERRING TO THE COAST LATER IN THE AFTERNOON. FCST
SOUNDINGS SHOW A LITTLE INSTABILITY BUT NOT ENOUGH OR DEEP ENOUGH TO
SUPPORT ANY THUNDER. OVERALL EXPECT A LOW QPF EVENT. THEN STRONG
COOL AND DRY ADVECTION KICKS IN LATER IN THE EVENING FOLLOWED BY A
TAPERING OFF TO NEAR NEUTRAL OVERNIGHT BUT NOT BEFORE THE LOW LEVELS
COOL SUFFICIENTLY TO SUPPORT LOWS IN THE LOW TO MID 30S. SIMILARLY
HIGHS ON WEDNESDAY HELD CLOSE TO 50 FOR ALL BUT FARTHEST SRN ZONES.
WEDNESDAY NIGHT LOWS WILL BE SIMILAR TO THOSE OF TUESDAY NIGHT.

&&

.LONG TERM /WEDNESDAY THROUGH MONDAY/...
AS OF 300 PM MONDAY...DETAILS FOR THE END OF THE WEEK AND START OF
NEXT WEEK ARE BECOMING A LITTLE CLEARER...HELPING INCREASE
CONFIDENCE LATE IN THE WEEK. COOL DRY HIGH PRESSURE WILL BE IN THE
PROCESS OF BUILDING IN AS THE PERIOD BEGINS. PRECIPITABLE WATER
VALUES WILL BE UNDER A QUARTER INCH THU AND FRI ALLOWING FOR
PLENTY OF SUNSHINE...THOUGH THERE COULD BE AN INCREASE IN HIGH
CLOUD LATER FRI AS MOISTURE ALOFT SPREADS IN FROM THE WEST.
DESPITE PLENTY OF SUNSHINE PARTIAL THICKNESS VALUES SUGGEST HIGHS
WILL STRUGGLE TO REACH 50 IN MOST AREAS THU. HIGHS FRI WILL BE A
FEW DEGREES WARMER THAN THU BUT STILL BELOW CLIMO.

SURFACE HIGH SHIFTS OFF THE COAST FRI INTO SAT WHILE A WEAK SOUTHERN
STREAM SYSTEM EMERGES FROM THE SOUTHWEST. WEAK COASTAL TROUGH
DEVELOPS SAT MORNING AS THE MID LEVEL TROUGH...WHICH REMAINS
POSITIVELY TILTED...CROSSES THE SOUTHERN CONUS. PROGRESSIVE NATURE
OF THE MID LEVEL FEATURE KEEPS THE SYSTEM WEAK AND FAST MOVING. THE
GEOGRAPHIC LOCATION OF THE SURFACE LOW SUGGESTS THE COASTAL TROUGH
WILL MOVE INLAND AND THAT A SIGNIFICANT WEDGE EVENT IS NOT LIKELY.
THIS WILL HELP KEEP TEMPERATURES ABOVE CLIMO FOR THE WEEKEND DESPITE
INCREASED CLOUD COVER AND ELEVATED PRECIP POTENTIAL. MEDIUM RANGE
GUIDANCE SHOWS SIGNIFICANT STRENGTHENING OF THE LOW IN NEW ENGLAND
AS MID LEVELS PHASE. THIS WILL IMPACT THE STRENGTH OF THE COLD
ADVECTION IN THE WAKE OF THE SUN COLD FRONT. FROPA TIMING SUN STILL
SOMEWHAT IN QUESTION WHICH HAS BIG IMPLICATIONS FOR HIGHS. CURRENT
EARLY TO MID MORNING TIMING WOULD LEAD TO TEMPS FALLING DURING SUN
AFTERNOON. MON IS LIKELY TO BE DRY BUT WITH TEMPERATURES BELOW CLIMO.

&&

.AVIATION /21Z MONDAY THROUGH SATURDAY/...
AS OF 18Z...VISIBILITIES IMPROVING...BUT IT LOOKS LIKE THE CEILING
WILL REMAIN IFR OR LOW THROUGH THE FORECAST PERIOD. THERE MAY BE A
BRIEF PERIOD ALONG THE COAST WHERE MVFR CONDITIONS WILL PREVAIL...AS
THE WEDGE WORKS INLAND FOR A FEW HOURS...BUT ONCE EVENING APPROACHES
LOOK FOR CONDITIONS TO GO BACK DOWN. OVERNIGHT...MOISTURE AHEAD OF A
COLD FRONT MAY PRODUCE SCATTERED PATCHES OF LIGHT RAIN...BUT THERE
PROBABLY WILL NOT BE ENOUGH INSTABILITY TO SCOUR OUT THE
FOG/STRATUS. TUESDAY...CONTINUED IFR AS LOW LEVEL MOISTURE WILL BE
STUBBORN TO LEAVE. SOME IMPROVEMENT IS POSSIBLE LATE IN THE FORECAST
PERIOD FROM WEST TO EAST AS THE COLD FRONT FINALLY PUSHES THROUGH.

EXTENDED OUTLOOK...MODERATE CONFIDENCE FOR VFR WEDNESDAY AND
THURSDAY...EXCEPT FOR POTENTIAL IFR STRATUS ALONG THE COAST ON
THURSDAY MORNING. SHOWERS POSSIBLE SATURDAY.

&&

.MARINE...
-- Changed Discussion --
NEAR TERM /THROUGH TONIGHT/...
AS OF 200 PM MONDAY...DENSE FOG ADVISORY EXPIRED AT 2 PM FOR NEAR
SHORE WATERS.

SW FLOW WILL INCREASE THROUGH TONIGHT AS GRADIENT TIGHTENS AHEAD
OF AN APPROACHING COLD FRONT. GREATEST CHALLENGE WILL BE HOW
QUICKLY THE INCREASE WILL COME AS A MORE STABLE ENVIRONMENT WILL
EXIST AS WAA ADVECTION RUNS OVER COOLER WATERS AS WATER TEMPS
REMAIN IN THE MID 50S. THIS WILL ALSO CREATE POTENTIAL FOR SEA FOG
ONCE AGAIN. THE SW WINDS WILL REMAIN HIGHER OVER WARMER GULF
STREAM WATERS KEEPING HIGHER SEAS OFF SHORE BUT THE OFF SHORE
COMPONENT THE FLOW SHOULD KEEP THE SEAS LOWER NEAR SHORE. SEAS
WILL INCREASE RAPIDLY BY MORNING AS GRADIENT TIGHTENS FURTHER AND AS
SOON AS SOME DEEPER MIXING OCCURS. FOR NOW WILL KEEP SEAS
INCREASING FROM 2 TO 4 FT MOST OF THE NIGHT TO 4 TO 6 FT BY
MORNING.

SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/...
AS OF 300 PM MONDAY...APPROACH OF COLD FRONT AND FLAT WAVE OF LOW
PRESSURE TO REALLY RAMP UP WINDS AND SEAS EARLY IN THE PERIOD. SMALL
CRAFT ADVISORY TO BE IN EFFECT FOR ALL ZONES THROUGH TUESDAY. SOME
QUESTIONS AS TO WHETHER WARM AIR ADVECTION AND/OR COOLER SSTS WILL
LEAD TO WIND SPEEDS A LITTLE LOWER THAN FORECAST OR DELAY THE ONSET
OF FORECAST WIND SPEEDS...AND THUS POSSIBLY THE SPEED AT WHICH SEAS
BUILD. FOR NOW HAVE CHOSEN TO ERR ON THE SIDE OF CAUTION AND SHOW A
FAIRLY AGGRESSIVE INC IN BOTH CLOSE TO WHAT THE WRF DEPICTS. HAVE
NOT RAISE SEAS QUITE AS HIGH AS LOCALLY GENERATED SWAN RUN WHICH
GIVES A BRIEF WINDOW OF 10 FOOTERS OUT NEAR FRYING PAN SHOALS.
CURRENT FCST A BLEND OF OLD FCST...SWAN...AND THE SLIGHTLY MORE TAME
WNA...ALL STILL LEADING TO A CONSIDERABLY MORE PESSIMISTIC THAN
PREVIOUS FORECASTS. FOR SIMILAR REASONS ITS TOUGH TO TELL A GOOD END
TIME FOR THE ADVISORY END TIME. 00Z SEES LIKE A GOOD APPROXIMATION
BUT A FEW ZONES MAY HOLD ON A BIT LONGER. MAIN COMPLICATING FACTOR
IS THAT END TIMES MAY VARY FROM N TO S. WIND REMAINS MAINLY OUT OF
THE NORTH FOR THE REMAINDER OF THE PERIOD. WIND AND SEAS WILL REMAIN
JUST BELOW CRITERIA WHERE SCEC HEADLINES ARE NEEDED.

LONG TERM /THURSDAY THROUGH SATURDAY/...
AS OF 300 PM MONDAY...HIGH PRESSURE BUILDING IN FROM THE WEST THU WILL
MOVE TO THE NC COAST ON FRI. REDUCTION IN PRESSURE GRADIENT WILL
ALLOW NORTHERLY WINDS TO DROP FROM 15 TO 20 KT THU TO 10 TO 15 KT
FRI. DIRECTION WILL VEER TO NORTHEAST DURING FRI AS CENTER OF HIGH
MOVES EAST OF HATTERAS. A WEAK COASTAL TROUGH WILL DEVELOP FRI NIGHT
WITH WINDS BECOMING EAST AND THEN SOUTHEAST SAT AS THE TROUGH MOVES
ONSHORE. SOUTHEAST FLOW WILL INCREASE BEHIND THE TROUGH WITH SPEEDS
IN THE 15 TO 20 KT RANGE BY THE END OF THE PERIOD. SEAS DROP FROM 3
TO 5 FT THU TO 2 TO 4 FT BY MIDDAY FRI. SEAS CONTINUE FALLING FRI
NIGHT INTO SAT...ENDING UP 2 TO 3 FT...BEFORE STARTING TO INCREASE
LATER SAT AS SOUTHEAST FLOW INCREASES.
-- End Changed Discussion --

&&

.ILM WATCHES/WARNINGS/ADVISORIES...
-- Changed Discussion --
SC...NONE.
NC...NONE.
MARINE...SMALL CRAFT ADVISORY FROM 3 AM TO 7 PM EST TUESDAY FOR AMZ250-
     252-254-256.
-- End Changed Discussion --

&&

$$
SYNOPSIS...
NEAR TERM...
SHORT TERM...
LONG TERM...
AVIATION...
MARINE...