238
FXUS62 KILM 200718
AFDILM
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE WILMINGTON NC
318 AM EDT SAT OCT 20 2018
SYNOPSIS
WARM AND MOIST AIR WILL RETURN TODAY WITH INCREASING CLOUDS AND
A CHANCE OF SHOWERS AHEAD OF AN APPROACHING COLD FRONT. THE
COLD FRONT WILL MOVE THROUGH THE AREA TONIGHT FOLLOWED BY
CANADIAN HIGH PRESSURE SUNDAY, BRINGING BELOW NORMAL
TEMPERATURES TO THE REGION THROUGH NEXT WEEK. CHANCES FOR RAIN
RETURN LATE NEXT WEEK.
NEAR TERM /THROUGH TONIGHT/
AS OF 3 AM SATURDAY...PRE-FRONTAL WARM ADVECTION WILL LEAD TO WEAK
ISENTROPIC UPGLIDE THAT WILL INCREASE CLOUD COVER AREA-WIDE THROUGH
MIDDAY SATURDAY. OTHER THAN A GLANCING COASTAL SHOT AT A LITTLE
LIGHT RAIN MOST PRECIP APPEAR TO STAY OFFSHORE. RAIN CHANCES THEN
SHIFT TO INLAND ZONES AS COLD FRONT AND HEIGHT FALLS IMPINGE UPON
THE AREA. THESE HEIGHT FALLS ARE WEAK AS ARE THE EMBEDDED VORTICITY
CENTERS SO RAIN CHANCES WILL STAY CAPPED IN THE CHANCE RANGE AND QPF
PROSPECTS ARE QUITE LOW. DEEP LAYER MOISTURE MOVES OFF THE COAST BY
EVENING AND THE COLD ADVECTION STARTS INTENSIFYING SOON THEREAFTER
BY ABOUT 03Z. THE COLD ADVECTION IN THE PRESENCE OF A CONTINUED
MODERATE GRADIENT SHOULD MAKE FOR A BREEZY SATURDAY NIGHT AS WIND
FIELDS REMAIN ALIGNED THROUGH A DEPTH OF ABOUT 4KFT. AHEAD OF THE
BOUNDARY THIS AFTERNOON WILL WARM TO NEAR 80 IN MOST PLACES. IN THE
CAA REGIME TONIGHT TEMPS WILL DIP INTO THE MID TO UPPER 40S, LIKELY
FASTER THAN PORTRAYED IN GUIDANCE.
SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/
AS OF 3 AM SATURDAY...DRY THROUGH THE SHORT TERM PERIOD AS COOL
HIGH PRESSURE BUILDS IN FROM THE WEST BEHIND A DEPARTING COLD
FRONT. WINDS SLOWLY DECREASE THROUGH THE DAY SUNDAY WITH A SUNNY
SKY AND HIGH TEMPS ONLY IN THE LWR 60S. CHILLY LOWS TO BEGIN
MONDAY...UPPER 30S INLAND AND 40S ALONG THE COASTAL ZONES,
ALTHOUGH LIGHTER WINDS, AS THE HIGH NEARS THE AREA. BEING THE
STRONGEST WINDS SINCE MICHAEL, IT'S POSSIBLE A FEW DANGLING
LIMBS, LEANED OR WEAKENED TREES COULD STILL DROP OR TOPPLE.
LONG TERM /TUESDAY THROUGH FRIDAY/
AS OF 300 PM FRIDAY...HIGH PRESSURE SETTLING OVER THE CAROLINAS
ON MON WILL KEEP COOL AND DRY WEATHER WITH TEMPS IN THE MID 60S
UNDER BRIGHT SUNSHINE. BY TUES THE HIGH WILL SHIFT OFF SHORE AS
A DRY COLD FRONT APPROACHES FROM THE NW. A BIT OF MOISTURE MAY
BE DRAWN UP AHEAD OF THIS FRONT WITH SOME CLOUDS AND PCP
POSSIBLE, MAINLY ALONG THE SC COAST OR OFF SHORE. INLAND AREAS
FROM I-95 WEST, MAY NOT SEE ANY EFFECTS FROM THIS DRY COLD
FRONT.
ANOTHER LARGE AREA OF HIGH PRESSURE WILL BUILD BEHIND THE FRONT
THROUGH MID WEEK WITH A PUSH OF COOLER AND DRIER AIR WED INTO
THURS. MODELS STILL INDICATING A WEDGE PATTERN SETTING UP FOR
LATE THURS INTO FRI WITH CLOUDS AND PCP SPREADING NORTHWARD AS
LOW PRESSURE MOVES ACROSS THE SOUTHEAST. LATEST MODEL RUNS SHOW
LOW DEEPENING OFF THE SOUTHEAST COAST HEADING INTO NEXT WEEKEND
WITH A DECENT AMOUNT OF RAINFALL POSSIBLE FRI OR SAT. EXPECT
LOWS IN THE 40S INLAND AND IN THE 50S ALONG THE COAST THROUGH
MUCH OF NEXT WEEK. TEMPS WILL BE IN THE 60S INLAND TO CLOSER TO
70 ALONG THE COAST.
AVIATION /07Z SATURDAY THROUGH WEDNESDAY/
AS OF 06Z...CEILINGS OVERSPREADING THE AREA BUT WILL TEND TO REMAIN
MVFR. SOME GUIDANCE HINTING AT LOWER HEIGHTS BUT HAVE BEEN OVERDONE
AS OF LATE AND GENERALLY DISCOUNTED. SOME LIGHT SHOWER ACTIVITY WILL
SPREAD WEST TO EAST ACROSS THE REGION BUT THEY WILL BE LIGHT ENOUGH
TO HAVE LITTLE TO NO MEANINGFUL EFFECTS ON TAFS. GUSTY NW WINDS THIS
EVENING WILL USHER IN CLEAR SKIES AS COLD AIR POURS INTO THE AREA.
EXTENDED OUTLOOK...EXTENDED OUTLOOK...COLD FRONT PUSHES THROUGH AREA
AT END OF TAF PERIOD,DRYING OUT CLOUDS AND REMOVING PRECIP CHANCES.
CONDITIONS IMPROVE TO VFR SUNDAY THROUGH EARLY NEXT WEEK.
MARINE
NEAR TERM /THROUGH TONIGHT/...
AS OF 3 AM SATURDAY...SOUTHWESTERLY PRE-FRONTAL FLOW REGIME TO
SEE WIND SPEED AND WAVE HEIGHTS BUILD AS THE APPROACHING FRONT
TIGHTENS THE GRADIENT. SMALL CRAFT ADVISORY CONDITIONS TO BE MET
BY THIS EVENING. THIS HEADLINE WILL NOT SUFFICE OVER NC WATERS
HOWEVER AS ONCE THE FRONT PUSHES THROUGH FORECAST SOUNDINGS SHOW
THAT THE WARM SSTS SHOULD MIX DOWN GALE FORCE GUSTS DUE TO
STEEP LOW LEVEL LAPSE RATES BEING MAINTAINED. GALE FORCE GUSTS
WILL ALSO BE POSSIBLE OVER SC WATERS BUT THEY MAY NOT BE QUITE
FREQUENT ENOUGH TO JUSTIFY THE WARNING.
SHORT TERM /SUNDAY THROUGH SUNDAY NIGHT/...
AS OF 3 AM SATURDAY...GALE FORCE GUSTS CONTINUE SUN MORNING,
AGAIN MOST FREQUENTLY OVER THE NORTH CAROLINA COASTAL WATERS
WHERE A GALE WARNING IS IN EFFECT. OCCASIONAL GUSTS TO 40 KT
NOT OUT OF THE QUESTION AS THE COLD AIR BREAKS OUT OVER THE
MILDER OCEAN WATERS. THE SLIGHT OFFSHORE TRAJECTORY WILL LIMIT
SEA-HEIGHT GROWTH OVER THE 0-20 NM WATERS, BUT OUTER PORTIONS
MAY SEE 6-7 FEET. THE SEA SPECTRUM WILL BE DOMINATED BY NORTH
WAVES EVERY 6 SECONDS, MAKING FOR STEEP AND TREACHEROUS WAVE
FACES. WINDS WILL EASE BY SUNDAY AFTERNOON, AS THE CENTER OF THE
APPROACHING HIGH NEARS THE AREA.
LONG TERM /MONDAY THROUGH WEDNESDAY/...
AS OF 300 PM FRIDAY...COOL CANADIAN HIGH PRESSURE WILL SETTLE
OVER THE WATERS ON MON WITH THE CENTER JUST INLAND AND NORTH
BEFORE SHIFTING FURTHER OFF SHORE THROUGH TUES. A DRY COLD FRONT
WILL CROSS THE WATER TUES NIGHT WITH ANOTHER LARGE AREA OF HIGH
PRESSURE BUILDING DOWN THROUGH MID WEEK. THIS WILL PRODUCE
LIGHT AND MORE VARIABLE AND VEERING WINDS MON INTO TUES, 10 KTS
OR LESS WITH SEAS LESS THAN 3 FT.
A NORTHERLY SURGE BEHIND COLD FRONT WILL PRODUCE A FAIRLY RAPID
INCREASE IN WINDS AND SEAS LATE WED INTO WED NIGHT. THE COLD
AIR RUSHING OVER THE WARMER WATERS WILL KEEP THE MARINE LAYER
WELL MIXED WITH GUSTY NORTHERLY WINDS WED NIGHT INTO THURS. N-NE
WINDS WILL INCREASE TO 15 TO 25 KTS WITH SCA CONDITIONS POSSIBLE
WED NIGHT.
ILM WATCHES/WARNINGS/ADVISORIES
SC...NONE.
NC...BEACH HAZARDS STATEMENT FROM 6 AM EDT THIS MORNING THROUGH
THIS EVENING FOR NCZ110.
MARINE...SMALL CRAFT ADVISORY FROM 11 PM THIS EVENING TO 2 PM EDT
SUNDAY FOR AMZ254-256.
GALE WARNING FROM 1 AM TO NOON EDT SUNDAY FOR AMZ250-252.
SYNOPSIS...
NEAR TERM...III/MBB
SHORT TERM...MJC/MAS/SRP
LONG TERM...RGZ
AVIATION...III/MBB/21
MARINE...
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