Area Forecast Discussion
Issued by NWS Wilmington, NC

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000
FXUS62 KILM 220240
AFDILM

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE WILMINGTON NC
940 PM EST SUN DEC 21 2014

.SYNOPSIS...
RAIN IS EXPECTED TO OVERSPREAD THE AREA TONIGHT AS LOW PRESSURE
MOVES UP THE CAROLINA COAST. HIGH PRESSURE WILL BRING COOL AND
CLOUDY CONDITIONS INTO TUESDAY. AN APPROACHING AND STRONG COLD
FRONT WILL BRING SHOWERS AND A FEW THUNDERSTORMS LATE TUESDAY AND
WEDNESDAY. DRIER AIR IS EXPECTED TO BUILD IN ON CHRISTMAS DAY AS
HIGH PRESSURE MOVES ACROSS THE AREA. A COLD FRONT MAY IMPACT THE
CAROLINAS LATE NEXT WEEKEND.

&&

.NEAR TERM /THROUGH MONDAY/...
AS OF 9 PM SUNDAY...RADAR TRENDS NOW REFLECTING RECENT FORECAST
EXPECTATIONS...AS EXPANDING STRATIFORM RAINFALL WITH EMBEDDED
HEAVY SHOWER POCKETS TRACK FROM SW TO NE OVER SC PRESENTLY. AT
THE MOMENT IT APPEARS THAT UPSTREAM COVERAGE OF RAIN MAY BRING
DECENT MEASURES TO INLAND AND COASTAL LOCALS OF NE SC AND SE NC.
ESTIMATES THROUGH 12Z/7AM MONDAY 0.10-0.25 INCHES...WITH A FEW
SPOTS APT TO GAIN MORE GIVEN CONVECTIVE ELEMENTS WITHIN THE -RA.

TEMPERATURES FOR THE MOST PART TO LEVEL OFF INTO DAYBREAK MONDAY
AMID THE WET FORECAST...PERHAPS WARMING A FEW DEGREES NEAR THE
COAST AND DROPPING ANOTHER FEW DEGREES WELL INLAND WHERE LARGER
DEWPOINT DEPRESSIONS COULD LEAD TO ADDITIONAL COOLING AS RAIN SETS
IN. THIS IS SUGGESTED BY THE LATEST LAV/LAMP GUIDANCE AS WELL AS
NCEP SREF 00Z MONDAY OUTPUT.

&&

.SHORT TERM /MONDAY NIGHT THROUGH TUESDAY NIGHT/...
AS OF 300 PM SUNDAY...A WEAK WAVE OF LOW PRESSURE WILL BE MOVING
UP THE COAST AND LIFTING N OF THE AREA MON MORNING. THIS SHOULD
TAKE THE MEASURABLE RAINFALL WITH IT. OTHERWISE HIGH PRESSURE
ACROSS THE CANADIAN MARITIMES IS EXPECTED TO WEDGE STRONGLY ACROSS
THE CAROLINAS. A VERY PRONOUNCED SUBSIDENCE INVERSION WILL TRAP
LOW LEVEL MOISTURE IN PLACE LEADING TO A PROLONGED PERIOD OF
WIDESPREAD STRATUS AND PATCHY DRIZZLE MON AND MON NIGHT. THERE
MAY ALSO BE SOME FOG AROUND MON NIGHT.

THE WEDGE IS EXPECTED TO HANG ON INTO TUE. A COASTAL TROUGH/WARM
FRONT WILL STRUGGLE TO DISLODGE THE WEDGE LATER TUE AND TUE NIGHT.
LOW PRESSURE IS EXPECTED TO MOVE OUT OF THE GULF OF MEXICO AND UP
THROUGH THE TENNESSEE AND OHIO VALLEYS TUE NIGHT AND WED MORNING.
THIS SHOULD FINALLY PROVIDE THE IMPETUS TO DRIVE THE WARM FRONT N
OF THE AREA AHEAD OF A STRONG COLD FRONT WEST OF THE APPALACHIANS.
WE MAY EXPERIENCE SOME SEA FOG ALONG THE COAST LATER TUE AND TUE
NIGHT AS WARM AND MOIST AIR OVERSPREADS THE AREA.

MODELS ARE PORTRAYING A HIGH SHEAR...LOW CAPE ENVIRONMENT
DEVELOPING BEHIND THE WARM FRONT. WILL MAINTAIN MENTION OF
THUNDERSTORMS TUE NIGHT AND THESE STORMS ARE EXPECTED TO REMAIN
WITH US ON WED AHEAD OF A STRONG COLD FRONT. MIXED LAYER CAPE
VALUES MAY ONLY REACH 500 J/KG...BUT 0-3 KM AGL BULK SHEAR VALUES
REACH 40-45 KT TUE NIGHT AS LOW LEVEL SW WINDS INCREASE TO 40 TO
45 KT AND THEN SLIGHTLY HIGHER ON WED. THESE ARE INDICATIONS THAT
SOME THUNDERSTORMS MAY BE AT LEAST STRONG LATE TUE NIGHT AND ON
WED. WILL TREND POPS HIGHER TUE AND ESPECIALLY TUE NIGHT...
REACHING 100 PERCENT.

WIDESPREAD CLOUDS SHOULD KEEP TEMPS RATHER COOL WITH A RATHER FLAT
TEMP CURVE. HIGHS ON MON WILL ONLY BE IN THE 40S WITH ANY LOWER
50S CONFINED TO THE COAST AND PERHAPS THE SOUTH SANTEE RIVER AREA.
LOWS MON NIGHT WILL BE IN THE LOWER TO MID 40S. TEMPS TUE WILL BE
TRICKY...IF THE WEDGE HOLDS STRONGLY ALL DAY...THEN HIGHS WOULD
BE SIMILAR TO MON. HOWEVER...ANY SUBSTANTIAL EROSION AND TEMPS
WOULD BE SIGNIFICANTLY HIGHER. THIS FORECAST PLAYS THE MIDDLE OF
THE ROAD FOR NOW WITH HIGHS IN THE 50S...COOLEST ACROSS THE I-95
CORRIDOR AND WESTWARD. TUE NIGHT...LOWS SHOULD OCCUR IN THE EARLY
EVE WITH TEMPS CLIMBING THROUGH THE LATE EVE AND OVERNIGHT HOURS.

&&

.LONG TERM /WEDNESDAY THROUGH SUNDAY/...
AS OF 300 PM SUNDAY...THERE WILL BE A WARM AND WET START TO THE LONG
TERM PERIOD. A DEEP MID TO UPPER TROUGH EXTENDING FROM THE UPPER
GREAT LAKES DOWN TO THE GULF COAST WILL PRODUCE A DEEP MOIST
SOUTHERLY FLOW OUT AHEAD OF IT. THIS WILL STREAM UP THROUGH THE
SOUTHEAST WITH AN INCREASING LOW LEVEL JET REACHING UP TO 50 KT BY
THE AFTERNOON. THIS WILL ACT TO FUNNEL PLENTY OF MOISTURE AND WARM
AIR INTO THE CAROLINAS AS SYSTEM MOVES EAST PUSHING A COLD FRONT
INTO THE CAROLINAS BY WED EVE AND OFF SHORE BY THURS MORNING. PCP
WATER VALUES REACH UP TO 2 INCHES ALONG THE COAST BY WED AFTERNOON
AND TEMPS WILL REACH INTO THE 70S IN STRONG WAA. BETTER DYNAMICS
ALOFT WILL AID IN POTENTIAL FOR STRONGER THUNDERSTORMS WITH GUSTY
WINDS THROUGH WED AFTN. OVERALL EXPECT BEST CHC OF SHOWERS AND
THUNDERSTORMS WITH HEAVIER RAIN AND GUSTY WINDS WED AFTN INTO THE
EARLY EVE AHEAD OF COLD FRONT.

MODELS SEEM A LITTLE SLOWER WITH COLD FRONT PASSAGE BUT EXPECT THE
DIGGING MID TO UPPER TROUGH TO PUSH THE COLD FRONT THROUGH WED NIGHT
BEFORE UPPER TROUGH FINALLY MOVES OFF SHORE BY THURS MORNING WITH
DRIER AND COOLER WEATHER FOR CHRISTMAS DAY. EXPECT CLEARING SKIES
THROUGH CHRISTMAS MORNING AND INCREASING SUNSHINE AND GUSTY WINDS
THROUGH THE DAY. TEMPS WILL RUN A GOOD 10 DEGREES COOLER THAN THE
DAY BEFORE.

HIGH PRESSURE WILL BUILD UP FORM THE GULF COAST THROUGH LATE THURS
INTO FRI. IT WILL REMAIN ELONGATED UP ALONG THE COAST AND THEN SLIP
FARTHER OFF SHORE THROUGH FRI INTO SAT AT A COLD FRONT APPROACHES
FROM THE W-NW. THE COOLER W-NW FLOW WILL SHIFT AROUND BY FRI TO W-SW
AS COLD FRONT APPROACHES THE CAROLINAS FROM THE WEST. DO NOT EXPECT
MUCH IN THE WAY OF MOISTURE RETURN AHEAD OF THIS FRONT AND FOR NOW
WILL KEEP WITH A DRIER FROPA FOR SAT NIGHT. THE W-SW FLOW SHOULD
HELP TO KICK TEMPS BACK UP ABOVE NORMAL FRI AND SAT.

MODELS SHOWING QUITE DIFFERENT SOLUTIONS WHEN IT COMES TO THE
WEEKEND. GFS SHOWS A DRY FRONTAL PASSAGE WITH DRY HIGH PRESSURE
BUILDING IN BY SUNDAY. THE ECMWF SHOWS A WAVE OF LOW PRESSURE
DEVELOPING ALONG THE FRONT ON SATURDAY WITH GREATER POTENTIAL FOR
PCP THROUGH SAT INTO SUN AS THE LOW MOVES UP THROUGH THE SOUTHEAST
AND FINALLY BRINGS FRONT THROUGH SUN EVENING. I WENT WITH A DRIER
SOLUTION OVERALL BUT DID PUT SOME CLOUDS AND LOW END POPS IN THE
FORECAST FOR THE WEEKEND.

&&

.AVIATION /03Z MONDAY THROUGH FRIDAY/...
AS OF 02Z...VFR CONDITIONS THIS EVENING WILL QUICKLY DETERIORATE
OVERNIGHT AS LOW PRESSURE DEVELOPS ALONG AN OFFSHORE COASTAL
TROUGH. CURRENT RADAR IMAGERY SHOWS SOME -RA/DZ MAINLY IMPACTING
THE COASTAL TERMINALS ATTM...WITH SOME MVFR CIGS ALREADY BEING
REPORTED. THE BEST LIFT FOR ADDITIONAL PRECIP WILL OCCUR AFTER
MIDNIGHT AND INTO MON MORNING AS A SFC LOW MOVES UP THE COAST.
KMYR/KCRE WILL LIKELY BE THE FIRST SITES TO SEE IFR CIGS
DEVELOP...FOLLOWED SOON AFTER BY KILM AROUND 06Z. BY
DAYBREAK...EXPECT WIDESPREAD IFR/LIFR CIGS AND -RA AT ALL
TERMINALS. NORTHEAST WINDS AROUND 10 KT WILL CONTINUE THROUGH THE
MORNING AS THE OFFSHORE LOW STRENGTHENS A BIT AND MOVES UP THE
COAST. THE RAIN MAY TAPER OFF BY MIDDAY...BUT IFR CIGS WILL
PERSIST THROUGH THE END OF THE PERIOD WITH COOL MOIST AIR LOCKED
IN BELOW 1KFT.

EXTENDED OUTLOOK...MVFR/IFR CIGS EARLY TUE MORNING WITH INCREASING
CHANCES OF SHOWERS/TEMPO MVFR DURING THE DAY. EXPECT SHOWERS/MVFR
AND GUSTY WINDS WED AHEAD OF A COLD FRONT. GUSTY WEST WINDS AND VFR
THU BEHIND THE FRONT. VFR ON FRI.

&&

.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 940 PM SUNDAY...SMALL CRAFT ADVISORY EXTENDED UNTIL 9 AM NC
WATERS AND 6 AM SC WATERS. ADVISORY GUSTS WILL LIKELY STICK AROUND
AND THIS WILL AGITATE SEAS...AND A RECOVERY TIME OF 6 FOOT PLUS
SEAS OFFSHORE IS ANTICIPATED. PRESSURE GRADIENT WILL REMAIN CRAMPED
BETWEEN HIGH PRESSURE BUILDING DOWN THE COAST AND A SURFACE LOW
MOVING NE ALONG THE COAST. THE PINCHED GRADIENT WILL LIFT NORTH
AND WEST AS THE LOW APPROACHES LATER TONIGHT...MOVING STRONGEST
WINDS NORTH OF THE SC WATERS. AS A RESULT SCA WILL CONTINUE FOR NC
WATERS THROUGH THE END OF THE PERIOD BUT FOR SC WATERS SCA WILL
END BY MIDNIGHT.

BUOY 41013 CONTINUES REPORTING 6 TO 7 FT SEAS AND ANTICIPATED
PROLONGED NORTHEAST FLOW IN THE 15 TO 20 KT RANGE SHOULD PUSH SEAS
OVER 6 FT INTO THE OUTER EDGES OF THE MARINE ZONES. THIS EVENT WILL
BE ON THE MARGINAL SIDE WITH CONDITIONS NOWHERE NEAR SCA THRESHOLDS
CLOSE TO THE COAST...ESPECIALLY IN AMZ252. SEAS WILL RANGE FROM 4 TO
6 FT WELL AWAY FROM SHORE AND IN WATERS EXPOSED TO EXTENDED
NORTHEAST FETCH WHILE WATERS CLOSE TO SHORE AND SHELTERED FROM
NORTHEAST FLOW WILL RUN 1 TO 3 FT.

SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/...
AS OF 300 PM SUNDAY...WEAK WAVE OF LOW PRESSURE WILL BE LIFTING N
ALONG THE COAST MONDAY. HIGH PRESSURE TO OUR NORTH WILL BUILD
STRONGLY IN THE WAKE OF THIS WAVE. THIS WEDGE WILL BEGIN TO BREAK
DOWN TUESDAY AS A COASTAL TROUGH BEGINS TO STRENGTHEN. THIS
TROUGH/WARM FRONT WILL LIFT ACROSS THE WATERS LATE TUE AND TUE
NIGHT. N TO NE WINDS MON AND MON NIGHT ARE EXPECTED TO VEER TO A
MORE EASTERLY DIRECTION DURING TUE AND THEN TO SE LATE TUE AND TUE
NIGHT. THE STRONGEST WINDS THIS PERIOD ARE EXPECTED TUE NIGHT...UP
TO AROUND 20 KT. SEAS WILL BE NEAR 3 FT MOST OF THE PERIOD. THERE
STILL MAY BE SOME 4 FT SEAS ACROSS PORTIONS OF THE WATERS MON
MORNING. HOWEVER...SEAS WILL BUILD TUE NIGHT AND SHOULD EXCEED 6
FT OVERNIGHT. A SMALL CRAFT ADVISORY WILL BE LIKELY LATE TUE NIGHT
AND BEYOND. AS WARMER AND MORE MOIST AIR WORKS ACROSS THE WATERS
LATER TUE AND ESPECIALLY TUE NIGHT...THE RISK FOR SEA FOG AND
STRATUS WILL INCREASE. POOR VISIBILITIES MAY DEVELOP ACROSS THE
WATERS DURING THIS TIME.

LONG TERM /WEDNESDAY THROUGH FRIDAY/...
AS OF 300 PM SUNDAY...A LARGE AND POTENT STORM SYSTEM WILL PUSH A
COLD FRONT EAST WITH INCREASING SOUTHERLY WINDS IN A TIGHTENING
GRADIENT FLOW THROUGH WED. WINDS WILL BE UP TO 15 TO 25 KT AHEAD
OF THE COLD FRONT. WNA CONTINUES TO SHOW SEAS RAMPING UP ABOVE 6
FT BY WED MORNING AND REACHING UP TO 7 TO 9 FT IN OUTER WATERS IN
STRONGER SW TO W FLOW AS FRONT MOVES THROUGH THE WATERS LATE WED
INTO WED NIGHT. EXPECT SMALL CRAFT CONDITIONS WED AND LASTING INTO
THURS WITH HIGHEST SEAS GETTING PUSHED FARTHER OFF SHORE IN
STRONGER W-NW FLOW BEHIND FRONT.

THE WINDS WILL BECOME WESTERLY AFTER MIDNIGHT WED AND WILL DIMINISH
AS THEY VEER AROUND TO THE NW TO N BECOMING 10 KTS OR LESS THROUGH
THURS INTO FRI MORNING. EXPECT SEAS TO DROP BELOW SCA THRESHOLDS BY
THURS AFTN ENDING UP AROUND 2 TO 4 FT BY THURS EVE AND DOWN FURTHER
TO 3 FT OR LESS BY FRI MORNING AS HIGH PRESSURE MOVES OVER THE
WATERS.

&&

.TIDES/COASTAL FLOODING...ELEVATED ASTRONOMICAL TIDES COUPLED WITH
A MODERATE ONSHORE PUSH OF WIND AND WAVES...WILL REQUIRE ISSUANCE
OF A COASTAL FLOOD ADVISORY FOR NEW HANOVER AND PENDER BEACHES FOR
HIGH WATER RUN-UP TO THE DUNES BY DAYBREAK MONDAY AND SEVERAL
HOURS AFTERWARD. IN SOME AREAS WATER MAY PUSH THROUGH LOW-LYING
DUNES ONTO LOCAL BEACH ROADWAYS. A MARGINAL EVENT FOR MINOR
THRESHOLDS BUT WARRANTED AS PEAK ASTRONOMICAL TIDES ARE ENHANCED
BY THE SYNOPTIC FLOW. PORTIONS OF CAROLINA BEACH ROAD MAY
EXPERIENCE A FEW INCHES OF WATER AROUND SUNRISE. TIDES WILL LOWER
BELOW FLOODING LEVELS BY MID-MORNING MONDAY.

&&

.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...COASTAL FLOOD ADVISORY FROM 6 AM TO 9 AM EST MONDAY FOR NCZ106-
     108.

MARINE...SMALL CRAFT ADVISORY UNTIL 6 AM EST MONDAY FOR AMZ254-256.

     SMALL CRAFT ADVISORY UNTIL 9 AM EST MONDAY FOR AMZ250-252.

&&

$$

SYNOPSIS...RJD/MJC
NEAR TERM...MJC
SHORT TERM...RJD
LONG TERM...RGZ
AVIATION...BJR
TIDES/COASTAL FLOODING...MJC






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