619
FXUS62 KILM 182051
AFDILM
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE WILMINGTON NC
351 PM EST WED DEC 18 2024
SYNOPSIS
UNSEASONABLY WARM WEATHER WILL CONTINUE INTO TONIGHT WITH
SHOWERS, FOG AND SEA FOG AHEAD OF A COLD FRONT. THE COLD FRONT
WILL MOVE THROUGH EARLY THURSDAY WITH A STRONGER COLD FRONT
TO FOLLOW FRIDAY EVENING, BRINGING MUCH COLDER TEMPERATURES
THIS WEEKEND INTO EARLY NEXT WEEK. ARCTIC HIGH PRESSURE WILL
MOVE OFF THE COAST MONDAY INTO TUESDAY ALLOWING FOR A WARM-UP
INTO MIDWEEK.
NEAR TERM /THROUGH THURSDAY/
MID TO UPPER TROUGH WILL PUSH A COLD FRONT THROUGH THE
CAROLINAS TONIGHT. WARM AND MOIST SOUTHERLY FLOW AHEAD OF IT
WILL PRODUCE ISO TO SCT SHOWERS. TEMPS AND DEWPOINTS ABOVE 60
WILL HELP TO PRODUCE ENOUGH INSTABILITY FOR ISO THUNDER IN SOME
OF THIS CONVECTIVE ACTIVITY. ALTHOUGH, POOR LAPSE RATES SHOULD
TEND TO HINDER ANY STRONGER STORMS. HEADING INTO TONIGHT, SHOULD
SEE A RETURN OF SOME FOG AND CONTINUED SEA FOG UNTIL THE WINDS
SHIFT AROUND TO THE WEST AS FRONT MAKES ITS WAY THROUGH INTO
EARLY THURS MORNING.
AS COLD FRONT MOVES THROUGH EARLY THURS MORNING, SHALLOW COLD
AIR WILL ADVECT IN, BUT LOOKING AT THE SOUNDINGS, A SHARP
FRONTAL INVERSION WILL SET UP WITH PLENTY OF WARM AND MOIST AIR
ABOVE IT. ONCE THE WINDS SHIFT AROUND TO THE NORTH AS FRONT
MOVES THROUGH, IT WILL SCOUR OUT ANY FOG, BUT A BLANKET OF LOW
STRATUS WILL DEVELOP ACROSS THE AREA POST FRONTAL LASTING AT
LEAST THROUGH THURS. SHORTWAVE WILL PASS THROUGH HEADING INTO
THE AFTERNOON AND THIS MAY HELP TO PRODUCE A BIT OF ELEVATED
INSTABILITY. COULD SEE A BIT OF PCP THROUGH AT THIS TIME. WINDS
WILL PICK UP OUT OF THE NORTH THROUGH THURS. OVERALL, A CLOUDY,
COOL AND DREARY DAY WITH SOME PCP. TEMPS WELL ABOVE NORMAL
TONIGHT, UP CLOSE TO 60 UNTIL AFTER MIDNIGHT ACROSS MUCH OF THE
AREA. ONCE THE FRONT PASSES, TEMPS WILL DROP INTO THE 50S MOST
PLACES. THEREFORE, THE HIGH TEMP FOR THE DAY WILL BE EARLY ON
WITH ONLY A FEW DEGREE RISE AT BEST AS SHALLOW COOL AIR MAKES IT
WAY INTO THE AREA.
SHORT TERM /THURSDAY NIGHT THROUGH FRIDAY NIGHT/
A DYNAMIC UPPER AIR PATTERN WILL EXIST ACROSS EASTERN NORTH AMERICA
LATE THIS WEEK: ONE SHORTWAVE WILL BE MOVING OFF THE CAROLINA COAST
THURSDAY EVENING, FOLLOWED BY A STRONGER ONE FRIDAY EVENING.
A SURFACE COLD FRONT SHOULD HAVE ALREADY MOVED OFF THE CAROLINA
COAST THURSDAY EVENING, PULLED OUT BY DEVELOPING LOW PRESSURE ON THE
GULF STREAM EAST OF THE SOUTH CAROLINA COAST. THIS COLD AIR WILL BE
VERY SHALLOW, BARELY EXTENDING UP TO 3000 FEET AGL.
ABOVE THIS LAYER, OUR CURRENT WARM AND HUMID AIRMASS WILL CONTINUE
ADVECT OVERHEAD. THE FRONTAL INVERSION BETWEEN THESE TWO AIRMASSES
WILL RETAIN SIGNIFICANT CLOUD COVER THURSDAY NIGHT. THIS COULD
PRODUCE SOME PATCHY DRIZZLE AND MAYBE EVEN ISOLATED SHOWERS DUE TO
STEEP LAPSE RATES BETWEEN THE FRONTAL INVERSION AND A SUBSIDENCE
INVERSION NEAR 8000 FEET AGL.
LIGHT NORTHERLY WINDS FRIDAY MORNING SHOULD SHIFT WESTERLY AND
INCREASE IN SPEED DURING THE AFTERNOON, SCOURING OUT ANY REMAINING
LOW CLOUDS OR SHOWERS. TEMPERATURES SHOULD RISE INTO THE UPPER 50S
TO LOWER 60S, THE LAST TIME FOR SEVERAL DAYS WE'LL BE ANYWHERE
NEAR NORMAL TEMPS. THE ARCTIC COLD FRONT WILL ARRIVE FRIDAY EVENING,
PUSHING OFFSHORE AND FOLLOWED SEVERAL DAYS OF COLD AND VERY DRY AIR ON
NORTHERLY WINDS.
LONG TERM /SATURDAY THROUGH TUESDAY/
THE FLOW BETWEEN 1040 MB HIGH PRESSURE OVER SOUTHERN ONTARIO AND 992
MB LOW PRESSURE OFF NOVA SCOTIA WILL ADVECT A COLD AND VERY DRY
ARCTIC AIRMASS ACROSS THE CAROLINAS THIS WEEKEND INTO EARLY NEXT
WEEK. THE COLDEST AIR SHOULD ARRIVE ON SUNDAY WHEN EVEN WITH NEARLY
FULL SUNSHINE HIGHS SHOULD ONLY REACH THE MID 40S, A GOOD 15 DEGREES
BELOW SEASONAL NORMS. SUNDAY NIGHT APPEARS TO BE OUR COLDEST NIGHT
OF THE EVENT AS WINDS DIE AWAY ENOUGH FOR A DISTINCT RADIATIONAL
INVERSION TO DEVELOP. GFS, ECMWF, AND NBM BLENDS HAVE ALL TRENDED
UPWARD WITH THEIR LOWS SUNDAY NIGHT WITH LOWER 20S EXPECTED FOR MOST
AREAS, EXCEPT SOME MID 20S ALONG THE BEACHES. NORMALLY COLD INLAND
SPOTS WILL ALMOST CERTAINLY DIP INTO THE TEENS.
THE ARCTIC HIGH WILL PUSH OFF THE EAST COAST MONDAY WITH WINDS
VEERING NORTHEASTERLY, THEN EASTERLY BY TUESDAY. THIS SHOULD BEGIN
TO ADVECT AN AIRMASS ONSHORE HEAVILY MODIFIED BY THE ATLANTIC AND
TEMPERATURES AND DEWPOINTS ARE EXPECTED TO RISE SIGNIFICANTLY. THERE
ARE SOME HINTS A WEAK COASTAL TROUGH MAY TRY TO DEVELOP TUESDAY, BUT
THE NEXT RAIN MAKER OF CONCERN IS A SOUTHERN STREAM SYSTEM THAT MAY
REACH THE CAROLINAS AS EARLY AS WEDNESDAY.
AVIATION /18Z WEDNESDAY THROUGH MONDAY/
ALTHOUGH FOG HAS LIFTED, LOW CEILINGS REMAIN MAINTAINING MVFR TO
IFR ACROSS MOST OF THE TERMINALS. VERY SATURATED LOW LEVELS
WILL REMAIN SUPPORTIVE OF IFR/LIFR IN FOG, LOW CLOUDS, SHOWERS
AHEAD OF COLD FRONT AND BEHIND IT AS SHALLOW COLD AIR ARRIVES
WITH WARM AIR REMAINING ALOFT THROUGH THURS. THE SHWRS ALONE
WILL BE MUCH LESS OF THE FLIGHT CATEGORY RESTRICTION AS THEY
SHOULD STAY LIGHT AND SCATTERED.
EXTENDED OUTLOOK...VFR CONDITIONS WILL NOT RETURN UNTIL
REINFORCING PUSH OF DEEP COLD AIR ARRIVES LATE FRIDAY AND THEN
WILL CONTINUE THROUGH THE END OF THE PERIOD.
MARINE
THROUGH THURSDAY...PERSISTENT SEA FOG SHOULD IMPROVE THROUGH
THIS AFTERNOON AS A MORE ONSHORE SE FLOW DEVELOPS, BUT AS WINDS
COME AROUND TO THE S-SW INTO THIS EVENING, SHOULD SEE ENOUGH
RESIDENCE TIME OF WARM MOIST AIR FLOWING OVER THE COLD SHELF
WATERS TO INCREASE THE POTENTIAL FOR SEA FOG ONCE AGAIN. THE SEA
FOG WILL COME TO AN END AS WINDS SHIFT AROUND AS FRONT PUSHES
OFFSHORE INTO THURS. THE WINDS WILL PICK UP OUT OF THE N-NE
BEHIND THE FRONT. THIS WILL PUSH SEAS UP TO 3 TO 5 FT AND
POSSIBLE SOME 6 FTERS IN THE OUTER WATERS BY LATER IN THE DAY.
OVERALL, WINDS AND SEAS WILL INCREASE WITH POSSIBLE SMALL CRAFT
CONDITIONS POSSIBLE OVER A PORTION OF THE WATERS BY LATE THURS.
THURSDAY NIGHT THROUGH MONDAY...A DYNAMIC WEATHER PATTERN WILL
CONTINUE THROUGH THE WEEKEND BEFORE CALMER WEATHER DEVELOPS NEXT
WEEK. A COLD FRONT WILL ALREADY BE OFFSHORE THURSDAY EVENING WITH
NORTHEASTERLY WINDS IN PLACE. WIND SPEEDS UP TO 20 KNOTS ARE
EXPECTED WITHIN 20 MILES OF SHORE THURSDAY NIGHT, DIMINISHING LATE
AS THE LOW PULLS EAST OF THE GULF STREAM AND AWAY FROM OUR AREA.
IT'S POSSIBLE SEAS COULD REACH 6 FEET FOR A PERIOD THURSDAY EVENING,
MAINLY NEAR AND NORTH OF CAPE FEAR.
A PERIOD OF FAIRLY LIGHT NORTHWEST WINDS ARE EXPECTED FRIDAY
MORNING, BUT A CLIPPER LOW MOVING RAPIDLY EAST ACROSS THE OHIO
VALLEY WILL DRAG AN ARCTIC COLD FRONT ACROSS THE AREA FRIDAY
EVENING. A BURST OF 20-25 KNOT NORTHWEST WINDS IS EXPECTED FRIDAY
NIGHT, VEERING NORTH ON SATURDAY AS ARCTIC HIGH PRESSURE BUILDS EAST
ACROSS SOUTHERN ONTARIO. WE'LL BE VERY CLOSE TO SMALL CRAFT ADVISORY
CRITERIA AGAIN FRIDAY NIGHT DURING THIS PERIOD OF STRONG OFFSHORE
WINDS.
WINDS SUNDAY THROUGH MONDAY WILL SLOWLY DIMINISH IN SPEED AND VEER
AS THE HIGH MOVES EASTWARD ACROSS NEW ENGLAND.
ILM WATCHES/WARNINGS/ADVISORIES
NC...NONE.
SC...NONE.
MARINE...DENSE FOG ADVISORY UNTIL 6 AM EST THURSDAY FOR AMZ250-252-254-
256.
SYNOPSIS...ILM
NEAR TERM...RGZ
SHORT TERM...TRA
LONG TERM...TRA
AVIATION...RGZ
MARINE...TRA/RGZ
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