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000
FXUS62 KILM 090746
AFDILM

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE WILMINGTON NC
346 AM EDT SUN MAR 9 2014

.SYNOPSIS...
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WARM AND DRY WEATHER WILL CONTINUE THROUGH TUESDAY. A WEAK AND
DRY COLD FRONT WILL PASS FROM NORTH TO SOUTH LATER TODAY. A
DEVELOPING LOW PRESSURE SYSTEM WILL PASS NORTH OF THE AREA
WEDNESDAY WITH A STRONG COLD FRONT PASSING WEDNESDAY NIGHT. HIGH
PRESSURE ACCOMPANIED WITH DRY CONDITIONS AND COOLER TEMPERATURES
ON THURSDAY AND FRIDAY. A WEAK COASTAL TROUGH MAY DEVELOP LATE IN
THE WEEK.
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&&

.NEAR TERM /THROUGH TONIGHT/...
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AS OF 3 AM SUNDAY...THE FORECAST AREA WILL REMAIN UNDER A RATHER
LOW AMPLITUDE LONGWAVE TROF THIS FCST PERIOD. MID LEVEL S/W TROF
IE. CLIPPER TYPE SYSTEM...TO REMAIN NORTH OF THE ILM CWA AS IT
PUSHES OFF THE NE-STATES AND MID-ATLANTIC COAST THIS AFTERNOON. AT
THE SFC...THE COLD FRONT ASSOCIATED WITH THIS CLIPPER TO DROP
SOUTHWARD ACROSS THE FA DURING TODAY. THE FRONT WILL BECOME
ORIENTED PARALLEL WITH THE MID TO UPPER FLOW...EXTENDING FROM WNW
TO ESE...AND THUS STALL SINCE NO AVBL DYNAMICS TO KEEP IT
PROGRESSING. NO PCPN ASSOCIATED WITH THIS FRONT. SOME LOW AND MID-
LEVEL MOISTURE ASSOCIATED WITH THE FRONT WILL RESULT IN PTLY CLDY
SKIES FOR WORST CASE SCENARIO...OTHERWISE PARTLY/MOSTLY SUNNY
SHOULD DO. SKIES TONIGHT WILL BE MOSTLY CLEAR AS DRIER AIR
ASSOCIATED WITH WNW-NW DOWNSLOPE FLOW ALOFT SCOURS OUT ANY
REMAINING MOISTURE ALOFT. AS FOR TEMPS...THIS DOWNSLOPE TRAJECTORY
IN THE MEAN FLOW WILL PUSH MAXES ABOVE THE AVAILABLE MOS GUIDANCE
TODAY. SHOULD SEE WIDESPREAD 70+ DEGREES FOR MAXES TODAY. ALONG
THE IMMEDIATE COAST WHERE ADJACENT ATLANTIC SSTS ARE IN THE 40S TO
LOW 50S...COULD KEEP MAX TEMPS ONLY IN THE 60S ONLY IF THE
DOWNSLOPE TRAJECTORY FLOW WEAKENS OR A PINNED SEA BREEZE DEVELOPS.
FOR TONIGHT...WEAK HIGH PRESSURE TO PREVAIL AFTER THE CFP EARLIER.
SOME DECENT RADIATIONAL COOLING POSSIBLE AND WILL INDICATE LOWS AT
OR BELOW THE LOWEST MINS AVAILABLE VIA MOS GUIDANCE.
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&&

.SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/...
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AS OF 3 AM SUNDAY...SURFACE HIGH OVER THE GULF COAST AT THE START OF
THE PERIOD WILL MOVE EAST ACROSS FL MON NIGHT AND EAST OF THE
BAHAMAS TUE. MID LEVEL PATTERN REMAINS FLAT INTO LATE TUE BEFORE A
SOUTHERN STREAM SHORTWAVE INDUCES SOME AMPLIFICATION OVER THE
SOUTHEAST. DEEP WESTERLY FLOW ALOFT MON AND TUE WILL KEEP THE REGION
DRY WITH MINIMAL CLOUDS AND TEMPERATURES ABOVE CLIMO. LATER TUE SOME
UPPER LEVEL MOISTURE AHEAD OF THE SOUTHERN STREAM SHORTWAVE MAY
SPREAD OVER THE AREA IN THE FORM OF CIRRUS BUT THIS WILL LIKELY BE
TOO LATE TO IMPACT TUE HIGHS. MOISTURE CONTINUES TO INCREASE TUE
NIGHT AS THE WAVE OPENS UP AND A NORTHERN STREAM SHORTWAVE BECOMES
DOMINANT. GIVEN THE MOIST ENVIRONMENT THINK ENOUGH POSITIVE
VORTICITY ADVECTION WILL EXIST AHEAD OF THE RAPIDLY WEAKENING WAVE
TO GENERATE SOME ISOLATED SHOWERS. PLAN TO MAINTAIN INHERITED CHC
POP TUE NIGHT WITH HIGHEST VALUES DURING THE LAST 6 HOURS OF THE
PERIOD.
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&&

.LONG TERM /WEDNESDAY THROUGH SATURDAY/...
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AS OF 3 AM SUNDAY...PERIOD BEGINS UNSETTLED WITH WEAKENING SOUTHERN
STREAM SYSTEM MOVING OFF THE COAST AHEAD OF A STRENGTHENING SYSTEM
MOVING INTO THE MID ATLANTIC. THE NORTHERN STREAM SHORTWAVE MOVING
THROUGH THE OH VALLEY WED AND DRIVING THE SURFACE CYCLOGENESIS WILL
HELP PUSH A COLD FRONT ACROSS THE AREA WED NIGHT. PRECIP CHANCES
CONTINUE TO LOOK MARGINAL AT BEST AS THE BULK OF THE FORCING AND
MOISTURE ASSOCIATED WITH THE STRENGTHENING NORTHERN SYSTEM REMAINS
DISPLACED WEST AND NORTH OF THE FORECAST AREA. ADDITIONALLY THE
REMAINS OF THE EXITING SOUTHERN STREAM SHORTWAVE MAY GENERATE WEAK
SUBSIDENCE OVER THE REGION AND THE WAVES EXIT HELPS CUT OFF THE
ALREADY LIMITED GULF MOISTURE FEED. PLAN TO MAINTAIN INHERITED MID
TO HIGH CHC POP WITH NO MENTION OF THUNDER AND LIMITED QPF.

STRONG BUT BRIEF COLD ADVECTION FOLLOWS THE COLD FRONT FOR THE
LATER HALF OF WED NIGHT AND FIRST PART OF THU. 850 TEMPS DROP BELOW
ZERO AND PARTIAL THICKNESS VALUES FOR THU SUGGEST HIGHS MORE TYPICAL
OF EARLY JAN AND HIGHS END UP 10 TO 15 DEGREES BELOW CLIMO. SURFACE
HIGH MOVES OVERHEAD THU NIGHT IN WHAT COULD BE A STRONG RADIATIONAL
COOLING SETUP. 850 TEMPS RIGHT AROUND ZERO AND PARTIAL THICKNESS
SUGGEST A FREEZE COULD BE A THREAT FOR AT LEAST A PORTION OF THE
AREA.

INCREASING SUN ANGLE AND LONGER DAYS HELP QUICKLY MODIFY THE AIR
MASS AND WHILE FRI IS LIKELY TO ONCE AGAIN BE BELOW CLIMO HIGHS
SHOULD END UP SEVERAL DEGREES WARMER. BY FRI NIGHT RETURN FLOW IS
FIRMLY ESTABLISHED WITH WEAK WARM ADVECTION KEEPING LOWS CLOSER TO
CLIMO. TEMPS NEAR TO SLIGHTLY ABOVE CLIMO SAT AND SAT NIGHT WITH
POTENTIAL FOR WEAK COASTAL TROUGH DEVELOPMENT LATE IN THE PERIOD. AT
THIS POINT DOES NOT APPEAR THE FEATURE WILL BE OF STRENGTH TO
WARRANT INCLUSION OF POP IN THE FORECAST.
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&&

.AVIATION /07Z SUNDAY THROUGH THURSDAY/...
AS OF 06Z...VFR WILL PREVAIL OVERNIGHT AS SW-WSW WINDS AROUND 5 KTS
SHOULD KEEP THE BOUNDARY LAYER MIXED ENOUGH TO PREVENT ANY FOG
FORMATION. A WEAK COLD FRONT DROPPING SOUTHWARD...WILL REACH THE
FORECAST AREA LATER THIS MORNING...AND SOUTH OF THE FORECAST AREA
BY SUNSET. WINDS WILL SHIFT AND VEER TO THE WNW AT 5 TO 10 KTS
DURING THE DAYTIME MORNING HOURS...AND FURTHER VEER TO THE NW
AROUND 10 KT BY MIDDAY THE FRONT MAY BE ACCOMPANIED BY SCATTERED
MID-LEVEL CLOUDS AND/OR LOW LEVEL SCATTERED STRATOCU/CUMULUS
CLOUDS DURING AND AFTER THE CFP. BUT OTHERWISE...ITS AVIATION
IMPACTS WILL BE LIMITED WITH NO PCPN EXPECTED. WITH DECENT WINDS
PROGGED AT WNW 20 TO 40 KT BETWEEN 850-700MB VIA MODEL TIME
HEIGHT DISPLAY...SEA BREEZE DEVELOPMENT WILL BE DIFFICULT. IF ITS
ABLE TO FORM...IT WILL LIKELY BE CONFINED MAINLY ALONG THE
IMMEDIATE COAST...POSSIBLY AND BRIEFLY BACKING THE WINDS TO THE
S-SW ACROSS BOTH MYRTLES DURING THE MID-LATE AFTERNOON. OVERALL...
SURFACE WINDS ARE EXPECTED TO BECOME CALM OR VARIABLE 2 KT OR
LESS. WITH FAVORABLE RADIATIONAL COOLING CONDITIONS SHAPING UP FOR
EARLY MONDAY...FOG WILL LIKELY BECOME AN ISSUE ACROSS THE
TERMINALS...MAINLY AFTER 06Z MON AND JUST BEYOND THE SCOPE OF THIS
FORECAST.

EXTENDED OUTLOOK...MVFR/IFR VSBYS POSSIBLE MONDAY MORNING FROM FOG.
OTHERWISE EXPECT VFR THROUGH TUESDAY. CHANCE OF SHOWERS AND
ASSOCIATED CEILINGS WITH MVFR/IFR CONDITIONS ON WEDNESDAY. VFR ON
THURSDAY.

&&

.MARINE...
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NEAR TERM /THROUGH TONIGHT/...
AS OF 3 AM SUNDAY...COLD FRONTAL PASSAGE...FROM NORTH TO
SOUTH...TO OCCUR LATER THIS MORNING THROUGH SUNSET. CAN EXPECT
SCATTERED CLOUDINESS ASSOCIATED WITH THIS FRONT...HOWEVER WITH
LIMITED DYNAMICS AND MOISTURE AVAILABLE...EXPECT A PCPN-FREE CFP.
SW TO W WINDS WILL PEAK THIS MORNING AHEAD OF THE FRONT...THEN
VEER TO THE NW AT AROUND 15 KT IN THE WAKE OF THE CFP AS IT MAKES
ITS TREK SOUTHWARD. WINDS WILL FURTHER DIMINISH TONIGHT AS WEAK
HIGH PRESSURE AND RELAXED SFC PG PRODUCE A SOMEWHAT VARIABLE WIND
DIRECTION AT 10 KT. WILL TRY TO IDENTIFY A DOMINATING WIND
DIRECTION AS ADDITIONAL 06Z MODELS BECOME AVBL. SIGNIFICANT SEAS
WILL ALSO PEAK THIS MORNING...BASICALLY IN THE 2 TO 4 FOOT
RANGE...THEN SLOWLY SUBSIDE THROUGH TONIGHT TO AROUND 2 FT. AN
UNDERLYING 2 TO 2.5 FOOT EASTERLY GROUND SWELL AT 10 TO 12 SECOND
PERIODS REMAINS PRESENT AND WILL DEFINITELY BE PLAYER WITH SIG
SEAS THROUGH TONIGHT.

SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/...
AS OF 3 AM SUNDAY...LIGHT WEST TO SOUTHWEST FLOW WILL CONTINUE OVER
THE WATERS THROUGH THE PERIOD WITH A SLIGHT BUMP IN SPEEDS LATE TUE
AND TUE NIGHT. HIGH PRESSURE OVER THE GULF COAST AT THE START OF THE
PERIOD WILL MIGRATE WELL EAST OF FL TUE. GRADIENT WILL BECOME MORE
DEFINED AS WEAKENING SYSTEM MOVES ACROSS THE SOUTHEAST. THE RESULT
WILL BE WIND SPEEDS 10 KT OR LESS MON INCREASING TO 10 TO 15 KT LATE
TUE AND TUE NIGHT. SEAS 2 TO 3 FT MON INTO TUE BUILD TO 2 TO 4 FT
FOR TUE NIGHT.

LONG TERM /WEDNESDAY THROUGH THURSDAY/...
AS OF 3 AM SUNDAY...DEEPENING LOW OVER THE MID ATLANTIC REGION AND
COLD FRONT APPROACHING FROM THE WEST WILL TIGHTEN THE GRADIENT
WED...INCREASING SOUTHWEST FLOW TO A SOLID 20 KT WITH POTENTIAL FOR
20 TO 25 KT LATE IN THE DAY. COLD FRONT PUSHES ACROSS THE WATERS WED
NIGHT WITH STRONG COLD ADVECTION AND PINCHED GRADIENT KEEPING
NORTHWEST WINDS 20 TO 25 KT THROUGH WED NIGHT AND DURING PART OF THU
MORNING. AHEAD OF THE FRONT SEAS BUILD OVER 6 FT BY WED AFTERNOON
BUT DURATION ABOVE 6 FT WILL BE SHORT LIVED GIVEN THE ANTICIPATED
STRONG OFFSHORE FLOW WED NIGHT. GRADIENT SLOWLY WEAKENS DURING THU
WITH WINDS GRADUALLY VEERING TO NORTHEAST AND DROPPING BELOW 10 KT
THU NIGHT AS HIGH PRESSURE DRIFTS IN FROM THE WEST. SEAS THU
STEADILY FALL THROUGH THE DAY...DROPPING FROM 3 TO 5 FT IN THE
MORNING TO 2 TO 3 FT THU NIGHT.
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&&

.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...NONE.

&&

$$

NEAR TERM...DCH
SHORT TERM...III
LONG TERM...III
AVIATION...DCH/BJR