622
FXUS62 KILM 200533
AFDILM
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE WILMINGTON NC
1233 AM EST FRI DEC 20 2024
SYNOPSIS
LOW PRESSURE OFFSHORE WILL MAINTAIN CLOUDY, COOL WEATHER TONIGHT.
AN ARCTIC COLD FRONT WILL ARRIVE FRIDAY NIGHT, BRINGING MUCH
COLDER WEATHER FOR THE WEEKEND. HIGH PRESSURE WILL MOVE OFF THE
EAST COAST MONDAY. WARMER WEATHER SHOULD DEVELOP ALONG WITH
INCREASING RAIN CHANCES BY THE MIDDLE OF NEXT WEEK AS GULF
COAST LOW PRESSURE MOVES TOWARD THE CAROLINAS.
UPDATE
OVER LAND, GOING FORECAST WAS IN GOOD SHAPE THIS EVENING AND
LITTLE ADJUSTMENT WAS REQUIRED. OVER WATER, FORECAST THERE IS ON
TRACK AS WELL BUT A LITTLE AHEAD OF SCHEDULE IN TERMS OF
GUSTINESS OF WINDS WITHIN 20 NM. PLAN TO LIMIT GUSTS TO 20 KT
THIS UPDATE AND DROP THE SMALL CRAFT ADVISORY.
NEAR TERM /THROUGH TODAY/
THE COLD FRONT CONTINUES TO PUSH FARTHER OFFSHORE WITH LOW-LEVEL
MOISTURE/AMPLE CLOUD COVER LINGERING ACROSS THE FORECAST AREA AT THE
MOMENT. EXPECT CLOUDINESS TO CONTINUE TONIGHT W/ LOW-LEVEL
NORTHEASTERLY FLOW CONTINUING ALONG WITH SOME PATCHY LIGHT
DRIZZLE POSSIBLE. A VORTICITY MAX WILL SWEEP ACROSS THE
CAROLINAS DURING FRIDAY DRIVING ANOTHER FRONT ACROSS THE AREA.
PVA ASSOCIATED WITH THIS FEATURE AND ENOUGH MOISTURE FROM H85 TO
H6 WILL LIKELY SUPPORT SOME SHOWERS, ESPECIALLY LATE FRIDAY
MORNING THROUGH FRIDAY AFTERNOON. ALTHOUGH POPS ARE LOW OVERALL,
THE BEST CHANCES ARE EXPECTED ACROSS THE NORTHERN ZONES WITH
MINIMAL QPF. CLOUD COVER COULD IMPEDE HIGH TEMPERATURES
TOMORROW, AND FOR NOW FAVOR GOING A COUPLE DEGREES COOLER THAN
THE BLEND WHICH SUGGEST MID 50S ACROSS THE NORTHERN TIER TO THE
UPPER 50S TO AROUND FAR SOUTHERN AREAS.
SHORT TERM /TONIGHT THROUGH SUNDAY NIGHT/
AN IMPRESSIVE SHORTWAVE WILL SWING OFF THE NORTH CAROLINA COAST
FRIDAY NIGHT. SOME LINGERING SHOWERS OR SPRINKLES ARE POSSIBLE
DURING THE EVENING, ESPECIALLY ACROSS SE NORTH CAROLINA WHERE
SUFFICIENT LOW LEVEL MOISTURE AND REASONABLY STEEP LAPSE RATES WILL
COMMINGLE WITHIN THE LOWEST 300 MB OF THE ATMOSPHERE. RAPID
DRYING WILL OCCUR BY LATE EVENING AND SHOULD SCOUR ANY REMAINING
MOISTURE OFFSHORE.
THE REMAINDER OF FRIDAY NIGHT THROUGH THE WEEKEND WILL FEATURE
ADVECTION OF COLD AND DRY AIR SOUTHWARD ACROSS THE CAROLINAS BETWEEN
LOW PRESSURE MOVING INTO THE CANADIAN MARITIMES AND HIGH
PRESSURE MOVING EASTWARD ACROSS SOUTHERN ONTARIO AND INTO NEW
ENGLAND BY SUNDAY NIGHT. IT'S ESSENTIALLY JUST A TEMPERATURE
FORECAST AND IT LOOKS LIKE THIS WILL BE THE SECOND MOST INTENSE
COLD OUTBREAK OF THE SEASON JUST BEHIND DECEMBER 6-7.
LOWS SATURDAY NIGHT WILL BE TEMPERED BY WINDS AT 500-1000 FEET
AGL REMAINING IN THE 15-20 KNOT RANGE MOST OF NIGHT. THIS SHOULD
PREVENT THE ESTABLISHMENT OF A STRONG NOCTURNAL INVERSION AND
LOW TEMPERATURES WILL LIKELY HOLD IN THE MID 20S INLAND, BUT
WITH WIND CHILLS PERHAPS DIPPING DOWN INTO THE UPPER TEENS.
AFTER SUN ONLY BOOSTS TEMPERATURES INTO THE MID 40S SUNDAY,
SUNDAY NIGHT'S BETTER RADIATIONAL CONDITIONS COULD DROP INLAND
LOWS DOWN TO NEAR 20 WITH TEENS IN THE NORMAL COLD SPOTS. IT'S
INTERESTING THAT THE GFS HAS BECOME WARMER VERSUS ITS PRIOR RUNS
WHILE THE ECMWF HAS BECOME COOLER.
LONG TERM /MONDAY THROUGH THURSDAY/
HIGH PRESSURE WILL MOVE OFF THE NEW ENGLAND COAST MONDAY, BUT
THE SURFACE RIDGE AXIS WILL CONTINUE TO POKE INLAND ACROSS
VIRGINIA AND THE CAROLINAS THROUGH MONDAY NIGHT BEFORE WEAKENING
WITH THE DEVELOPMENT OF A WEAK COASTAL TROUGH FROM CAPE FEAR
TO THE FLORIDA EAST COAST. ENSEMBLE GUIDANCE SHOWS 20-30 PERCENT
POTENTIAL FOR LIGHT RAIN OR SHOWERS TUESDAY NIGHT OR WEDNESDAY
AS LOW LEVEL ISENTROPIC UPGLIDE DEVELOPS OVER THE WARM FRONTAL-
LIKE COASTAL TROUGH.
A SOUTHERN STREAM DISTURBANCE SHOULD APPROACH FROM THE WEST
WEDNESDAY AND THURSDAY. AN INVERTED SURFACE TROUGH OR WEAK AREA
OF LOW PRESSURE SHOULD APPROACH FROM THE GULF COAST AHEAD OF THE
TROUGH. THIS MAY ENHANCE RAINFALL POTENTIAL FURTHER, BUT I
HAVEN'T INCREASED POPS BEYOND 30 PERCENT GIVEN MODEL TIMING
DIFFERENCES AND THE EXTENDED TIME RANGE. THE AIRMASS SHOULD
MODIFY ENOUGH BEFORE ANY PRECIPITATION CHANCES DEVELOP THAT
EVERYTHING SHOULD BE LIQUID NEXT WEEK.
AVIATION /06Z FRIDAY THROUGH TUESDAY/
NO FOG THROUGH THE PERIOD BUT CEILINGS IN THE 1-2KFT RANGE TO
HANG TOUGH FOR MOST OF IT. A COLD FRONT WILL SWEEP THROUGH LATE
AFTERNOON/EVENING TURNING LIGHT AND VARIABLE WINDS MORE
NORTHWESTERLY. THE MID LEVEL TROUGH DRIVING THE FRONT COULD BE
STRONG ENOUGH TO SQUEEZE OUT A SHOWER THAT EFFECTS LBT AND/OR
ILM BUT AT THIS TIME THEY LOOK TOO LIGHT/SHORT-LIVED TO BE TAF-
WORTHY, IF THEY EVEN OCCUR AT ALL.
EXTENDED OUTLOOK...VFR CONDITIONS EXPECTED LATE FRIDAY,
CONTINUING THROUGH THE WEEKEND.
MARINE
THROUGH FRIDAY...THE COLD FRONT THAT PUSHED ACROSS THE WATERS THIS
MORNING WILL CONTINUE TO MOVE OFFSHORE THIS AFTERNOON/EVENING. NELY
WIND OF 20-25 KT W/ GUSTS TO 30 KT WILL CONTINUE IN ITS WAKE, MAINLY
FOR THE WATERS AROUND CAPE FEAR NORTHWARD. NO CHANGES PLANNED TO THE
SC.Y FOR THESE WATERS. AS LOW PRESSURE MOVES FROM OFF THE SC COAST
THIS AFTERNOON TO OFF THE OUTER BANKS FRIDAY THE FLOW WILL BACK TO
AN OFFSHORE DIRECTION. THE OFFSHORE FETCH WILL STRENGTHEN
DURING FRIDAY AFTERNOON AHEAD OF THE NEXT COLD FRONT. SEAS OF 5
TO 7 FT THIS AFTERNOON AND EARLY EVENING WILL SUBSIDE SOME
BEFORE INCREASING AGAIN DURING FRIDAY AFTERNOON, ESPECIALLY AWAY
FROM INSHORE AREAS. THE WATERS COULD SEE SOME LIGHT DRIZZLE
THIS AFTERNOON/EVENING, THEN A FEW SHOWERS ARE POSSIBLE FRIDAY
AFTERNOON AS THE NEXT FRONT APPROACHES.
FRIDAY NIGHT THROUGH TUESDAY...990 MB LOW PRESSURE OFF NEW
ENGLAND AND 1040 MB HIGH PRESSURE OVER SOUTHERN ONTARIO WILL
PUSH COLD NORTHERLY WINDS ACROSS THE CAROLINAS THIS WEEKEND.
WIND SPEEDS NEAR 20 KNOTS ARE EXPECTED FRIDAY NIGHT INTO
SATURDAY, WITH A SECOND SURGE FRIDAY NIGHT INTO SATURDAY
POSSIBLY BRINGING 15-20 KT WIND SPEEDS. WINDS SHOULD FINALLY
DIMINISH IN EARNEST MONDAY NIGHT INTO TUESDAY AS THE CANADIAN
HIGH REACHES THE EAST COAST.
LARGELY OFFSHORE WIND TRAJECTORIES WILL KEEP FETCH LENGTHS SHORT
AND SEAS SHOULD REMAIN BELOW 5 FEET WITHIN 20 MILES OF SHORE.
DOMINANT WAVE PERIODS WILL BE SHORT AND CHOPPY, SO EVEN 4 FEET
WILL BE UNCOMFORTABLE FOR SMALLER VESSELS. WAVE PERIODS SHOULD
LENGTHEN BY MONDAY NIGHT AND TUESDAY WITH 2-3 FOOT HEIGHTS
EXPECTED.
ILM WATCHES/WARNINGS/ADVISORIES
NC...NONE.
SC...NONE.
MARINE...NONE.
SYNOPSIS...TRA
UPDATE...31
NEAR TERM...TRA
SHORT TERM...TRA
LONG TERM...TRA
AVIATION...MBB
MARINE...TRA/SRP
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