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-- Discussion containing changed information from previous version are highlighted. --
000
FXUS62 KILM 081129
AFDILM

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE WILMINGTON NC
629 AM EST SAT MAR 8 2014

.SYNOPSIS...
HIGH PRESSURE WILL BUILD IN FOR THE WEEKEND...BRINGING DRY AND
MUCH WARMER CONDITIONS. DRY WEATHER WILL CONTINUE THROUGH TUESDAY.
A COLD FRONT WILL MOVE THROUGH DURING THE MIDDLE OF NEXT WEEK
BRINGING A CHANCE OF SHOWERS. HIGH PRESSURE AND DRY WEATHER WILL
RETURN BY LATE NEXT WEEK.

&&

.NEAR TERM /THROUGH TONIGHT/...
-- Changed Discussion --
AS OF 615 AM SATURDAY...SOUTHERN STREAM UPPER CLOSED LOW WELL
OFFSHORE FROM CAPE HATTERAS THIS MORNING...TO OPEN UP AS IT
PROGRESSES FURTHER EASTWARD AND AWAY FROM THE US MAINLAND. THIS
LEAVES UPPER FLOW SOMEWHAT TEMPORARILY FLATTENED ACROSS THE SE
U.S. COAST...INCLUDING THE ILM CWA. FOR LATE TONIGHT...A NORTHERN
STREAM LOW AMPLITUDE S/W CLIPPER UPPER TROF WILL DIVE SE AND REACH
THE NE U.S. AND MID-ATLANTIC STATES BY DAYBREAK SUNDAY. THE
BEARING IT HAS ON THE ILM CWA IS THAT THE SFC COLD FRONT
ACCOMPANYING THIS CLIPPER...WILL DROP SSE-WARD AND BE ON THE
DOORSTEPS OF THE ILM CWA...AFTER DAYBREAK SUN. MODELS INDICATE
SOME TIMING ISSUES AMONGST ONE ANOTHER WITH THE EVENTUAL PASSAGE
OF THIS COLD FRONT. NEVERTHELESS THEY DO AGREE ON A DRY PASSAGE
BOTH AHEAD AND ALONG IT. LATEST SAT IMAGERY TRENDS AND 00Z
GUIDANCE INDICATE MAINLY SUNNY SKIES TODAY AND A MOSTLY CLEAR
NIGHT TONIGHT. COULD OBSERVE UPSTREAM CI/CS MAKING IT TO THE
FA...HOWEVER IT SHOULD REMAIN ON THE THIN/TRANSPARENT SIDE. WITH
THE SFC RIDGE AXIS JUST OFF THE CAROLINA COAST...WINDS GENERALLY
WNW TO WSW TODAY. A VERY SHALLOW SEA BREEZE REMAINS POSSIBLE ALONG
THE IMMEDIATE COAST THIS AFTN AS TEMPS INLAND WARM WELL INTO THE
60S...WITH LOCAL SSTS BELOW NORMAL...AND ONLY IN THE UPPER 40S.
WITH RELATIVELY STRONG WINDS JUST ALOFT RUNNING 25 TO 35 KT...THE
SHALLOW SEA BREEZE WILL HAVE DIFFICULTY PUSHING WELL INLAND. FOR
TONIGHT...AHEAD OF THE APPROACHING SFC COLD FRONT...AND A SEMI-
TIGHTENED SFC PG...WINDS TO BECOME SW-WSW AROUND 5 MPH OR LESS
WHICH SHOULD KEEP FOG...IF ANY...TO A MINIMUM.. FOR TODAYS HIGHS
AND TONIGHT LOWS...VARIOUS MODEL MOS GUIDANCE SIMILAR AND HAVE
STAYED CLOSER TO ITS NUMBERS. EXCEPTIONS WILL BE ALONG THE
IMMEDIATE COAST...WHERE COOL SSTS WILL KEEP MAXES ONLY NEAR 60.
DUE TO A FULL DAYS WORTH OF INSOLATION...ADDED A FEW DEGREES AWAY
FROM THE COAST TO ACCOUNT FOR THE MARCH SUN.
-- End Changed Discussion --

&&

.SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/...
AS OF 3 AM SATURDAY...DRY BACKDOOR COLD FRONT WILL MOVE SOUTH ACROSS
THE AREA LATE SUN FOLLOWED BY A BRIEF PERIOD OF VERY WEAK COLD
ADVECTION SUN NIGHT. AHEAD OF THE FRONT LIGHT SOUTHWEST FLOW AND
SUNSHINE WILL PUSH HIGHS ABOVE CLIMO. PASSAGE OF FRONT MAY BE MARKED
BY AN INCREASE IN MID LEVEL CLOUD BUT MOISTURE AND DYNAMICS
SUPPORTIVE OF PRECIP ARE LACKING. TEMPS DROP TO NEAR CLIMO SUN NIGHT
BUT BY MON AM HIGH PRESSURE TO THE SOUTH STARTS EXPANDING NORTH. THE
RESULTING WEST TO SOUTHWEST LOW LEVEL FLOW AND DEEPER WESTERLY FLOW
ALOFT WILL KEEP THE REGION DRY AND NEARLY CLOUD FREE WITH TEMPS
ABOVE CLIMO MON AND MON NIGHT.

&&

.LONG TERM /TUESDAY THROUGH FRIDAY/...
AS OF 3 AM THURSDAY...SPLIT FLOW OVER THE WEST WILL TRANSLATE EAST
DURING THE WEEK WITH A GULF COAST SHORTWAVE AND NORTHERN STREAM
SHORTWAVE THE KEY PLAYERS. TUE WILL BE BENIGN WITH FLAT MID LEVEL
FLOW AND WEST TO SOUTHWEST LOW LEVEL FLOW KEEPING TEMPS ABOVE CLIMO.
CLOUDS WILL START TO INCREASE LATER TUE AS MOISTURE AHEAD OF THE
GULF COAST WAVE SPREADS OVER THE AREA.

STILL SOME UNCERTAINTY FOR WED INTO THU TIME PERIOD BUT MEDIUM RANGE
GUIDANCE IS TRENDING IN THE DIRECTION OF THE SOUTHERN STREAM WAVE
WEAKENING AS THE NORTHERN STREAM BECOMES MORE DOMINANT. WEAK LOW
PASSES NORTH OF THE AREA DURING WED WITH 5H TROUGH DROPPING INTO THE
MS VALLEY HELPING TO PUSH A COLD FRONT ACROSS THE AREA LATE WED
NIGHT OR EARLY THU. CONTINUES TO LOOK LIKE WEAK CONVECTION WILL BE
SUPPORTED AHEAD OF THE FRONT. UPWARD MOTION MAY BE HINDERED BY
SUBSIDENCE FOLLOWING THE REMAINS OF THE SOUTHERN STREAM SHORTWAVE.
SO WHILE THERE WILL BE PLENTY OF MOISTURE AND AN INCREASED CHC OF
SHOWERS DO NOT THINK THUNDER IS WARRANTED. COLD ADVECTION BEHIND THE
FRONT...ENHANCED BY PINCHED GRADIENT AS LOW DEEPENS OFF THE NEW
ENGLAND COAST...WILL KNOCK TEMPS BACK BELOW CLIMO FOR THE END OF THE
PERIOD. HOW COLD REMAINS A QUESTION WITH THE 00Z GFS SHOWING A
WEAKER 5H TROUGH THU/FRI AND THUS LESS COLD AIR COMPARED TO THE
ECMWF. NOT OPTING TO MAKE MANY CHANGES LATE IN THE PERIOD WITH
INHERITED TEMPS ON THE COOL SIDE OF THE MOS GUIDANCE...WHICH RELIES
HEAVILY ON CLIMO FOR D6 AND D7.

&&

.AVIATION /11Z SATURDAY THROUGH WEDNESDAY/...
AS OF 06Z...NO PCPN CHANCES...ALONG WITH MAINLY SKC CONDITIONS
THRUOUT THE 06Z ISSUANCE FORECAST PERIOD. ONLY CLOUDS TO AFFECT
THE TERMINALS WILL BE MAINLY THIN CI/CS. WITH LOW LEVEL MOISTURE
STILL IN ABUNDANCE...WILL INDICATE FOG IN THE 09Z- 13Z TIME FRAME
ESPECIALLY WHERE WINDS SUBSIDE BELOW 5 KT. FOR DAYLIGHT SATURDAY
     ANY FOG WILL DISSIPATE QUICKLY AS WESTERLY WINDS INCREASE AND
DRIER AIR OVERSPREADS THE FORECAST AREA. WINDS MAY GO SOUTHERLY
ALONG THE IMMEDIATE COAST AS WINDS BACK TO THE SOUTH IN RESPONSE
TO A SHALLOW SEA BREEZE AS TEMPS JUST INLAND FROM THE COAST WARM
UP WELL INTO THE 60S. COLD FRONT WILL BE APPROACHING FROM THE NW
SATURDAY NIGHT.

EXTENDED OUTLOOK...VFR WILL PREVAIL THROUGH TUESDAY. CHANCE OF
SHOWERS ON WEDNESDAY.

&&

.MARINE...
-- Changed Discussion --
NEAR TERM /THROUGH TONIGHT/...
AS OF 615 AM SATURDAY...WINDS AND SIGNIFICANT SEAS WILL REMAIN IN A
DIMINISHING AND SUBSIDING MODE TODAY...AND SOMEWHAT STABILIZE
TONIGHT. ALTHOUGH BOTH PARAMETERS HAVE BEEN DROPPING SLOWER THAN
GUIDANCE OVERNIGHT...WILL CONTINUE WITH THAT NOTION TODAY.

SCA AND SCEC HAS BEEN EXTENDED THROUGH NOON FOR BOTH THE ILM NC
WATERS AND THE ILM SC WATERS RESPECTIVELY. THE SLOWLY RELAXING SFC
PG AND PATTERN IN THE WAKE OF THE DEPARTING SOUTHERN STREAM
LOW...WILL RESULT IN NW 15 TO 20 KT...GUSTS UP TO 25 TO 30 KT IN
THE AM OUTER WATERS OFF CAPE FEAR...BACKING AND DIMINISHING TO
W-SW 10 TO 15 KT LATE THIS AFTERNOON AND TONIGHT. SIGNIFICANT SEAS
WILL BE IN A SLOW SUBSIDING TREND TODAY...AND STABILIZE-SOME
DURING TONIGHT. EVENTHOUGH THE SHORT PERIOD WIND DRIVEN WAVE
PORTION OF THE SIG. SEAS WILL BE DECREASING...AN UNDERLYING 3 TO 4
FOOT 10-12 SECOND PERIOD EASTERLY GROUND SWELL WILL REMAIN PRESENT
THRUOUT THIS FCST PERIOD. AS A RESULT...WILL KEEP SIGNIFICANT SEAS
1 TO 2 FEET HIER THAN SWAN/WAVEWATCH3 NUMBERS.

SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/...
AS OF 3 AM SATURDAY...LIGHT WEST TO SOUTHWEST FLOW FOR MUCH OF THE
PERIOD WILL BE DISRUPTED LATE SUN NIGHT AND EARLY MON BY PASSAGE OF
WEAK COLD FRONT. MINIMAL COLD ADVECTION AND LITTLE GRADIENT CHANGE
BEHIND THE FRONT WILL KEEP SPEEDS UNDER 10 KT INTO MON. WEST TO
SOUTHWEST FLOW WILL RETURN BY MIDDAY MON AS HIGH PRESSURE TO THE
SOUTH EXPANDS NORTH. SPEEDS MAY EXPERIENCE A SLIGHT BUMP IN SPEEDS
LATE MON AND MON NIGHT AS GRADIENT BECOMES A LITTLE MORE DEFINED.
SEAS WILL RUN 2 TO 3 FT FOR MUCH OF THE PERIOD.

LONG TERM /TUESDAY THROUGH WEDNESDAY/...
AS OF 3 AM SATURDAY...SOUTHWEST FLOW WILL INCREASE TUE INTO WED AS
STRONG COLD FRONT APPROACHES FROM THE WEST. STILL SOME UNCERTAINTY
IN THE EVOLUTION OF THE MID LEVEL PATTERN AND WHICH FEATURE WILL
BECOME DOMINANT BUT EITHER WAY A PERIOD OF SOUTHWEST WINDS
APPROACHING 20 KT IS EXPECTED DURING WED...JUST AHEAD OF THE COLD
FRONT. PROLONGED AND INCREASING SOUTHWEST FLOW WILL BUILD SEAS FROM
2 TO 4 FT ON TUE TO 3 TO 5 FT WED. A SCEC HEADLINE IS NOT OUT OF THE
QUESTION...ESPECIALLY FOR NC WATERS...AT THIS POINT BUT DO NOT THINK
CONDITIONS WILL WARRANT SCA. STRONG OFFSHORE FLOW DEVELOPS LATE IN
THE PERIOD BEHIND THE FRONT WITH THE COMBINATION OF PINCHED GRADIENT
AND COLD ADVECTION KEEPING SPEEDS CLOSE TO 20 KT. OFFSHORE DIRECTION
WILL KNOCK SEAS UNDER 5 FT SHORTLY AFTER THE FRONT PASSES.
-- End Changed Discussion --

&&

.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL NOON EST TODAY FOR AMZ250-252.

&&

$$
SYNOPSIS...III
NEAR TERM...DCH
SHORT TERM...III
LONG TERM...III
AVIATION...DCH/DL