Area Forecast Discussion
Issued by NWS Wilmington, NC

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000
FXUS62 KILM 190541
AFDILM

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE WILMINGTON NC
1241 AM EST FRI DEC 19 2014

.SYNOPSIS...
HIGH PRESSURE OVER THE GREAT LAKES WILL MOVE NORTH OF THE CAROLINAS
FRIDAY AND SATURDAY. LOW PRESSURE WILL DEVELOP ALONG THE GULF COAST
FRIDAY AND MOVE NORTHEAST ALONG THE CAROLINA COAST SATURDAY...
ACCOMPANIED BY RAIN AND COOL TEMPERATURES. A SECOND LOW COULD BRING
MORE CLOUDS AND RAIN MONDAY. A COLD FRONT WILL MOVE ACROSS THE AREA
TUESDAY NIGHT INTO WEDNESDAY...WITH COLD AND DRY WEATHER EXPECTED ON
CHRISTMAS DAY.

&&

.NEAR TERM /UNTIL 6 AM THIS MORNING/...
AS OF 12:30 AM FRIDAY...NO CHANGES TO THE FORECAST WITH THE LATEST
UPDATE. PREVIOUS DISCUSSION FOLLOWS:

SURFACE HIGH PRESSURE OVER THE WESTERN GREAT LAKES IS PUSHING A
CHILLY AIRMASS INTO THE CAROLINAS. 850 MB TEMPS AROUND +6C SHOULD
SLIP TO +4C BY DAYBREAK. A LITTLE CIRRUS WILL MOVE ACROSS FROM
TIME TO TIME...AS WILL SOME STRATOCUMULUS IN THE 5000-7000 FT
RANGE CURRENTLY OBSERVED WEST OF I-95. ANALYSIS OF MODEL RH AND
ISENTROPIC FIELDS INDICATES THIS STRATOCUMULUS SHOULD HAVE
TROUBLE MAKING IT TOO FAR EAST TONIGHT -- A STRIPE OF HIGHER RH
(60-75 PERCENT IN THE 800-850 MB LAYER) SHOULD EXTEND DOWN TO THE
COAST BY 12Z FRI BUT WITH WEAK ISENTROPIC DOWNGLIDE NOTED
THROUGHOUT THE 290-300K THETA SURFACES CLOUDS SHOULD BE ERODING AS
THEY PRESS EASTWARD. SKY COVER FORECASTS WILL REMAIN MOSTLY CLEAR
NEAR THE COAST WITH PARTLY CLOUDY INLAND.

ONLY SMALL TWEAKS HAVE BEEN MADE TO FORECAST LOWS OVERNIGHT...STILL
IN THE LOWER TO MID 30S FOR MOST AREAS EXCEPT FOR SOME UPPER 20S
ACROSS THE NORMALLY-COLDER POCOSIN SWAMPS OF SE NORTH CAROLINA.

&&

.SHORT TERM /6 AM THIS MORNING THROUGH SATURDAY NIGHT/...
AS OF 300 PM THURSDAY...STILL LOOKS LIKE IT WILL RAIN SAT...BUT
THE MODELS HAVE NOT ONLY BEEN GUIDING US TO A SLOWER PROGRESSION...
BUT NOW A DRIER AND MORE SUPPRESSED SOLUTION FOR OUR FORECAST
AREA. GIVEN THAT...HAVE DECIDED TO DIAL BACK SOME ON BOTH POPS AND
QPF. NEVERTHELESS...A SOUTHERN STREAM SHORTWAVE WILL MOVE OUT OF
THE SOUTHWESTERN U.S. FRI AND THEN ACROSS THE MID SOUTH AND
SOUTHEAST FRI NIGHT AND SAT. HIGH PRESSURE IS EXPECTED TO BEGIN
WEDGING INTO THE CAROLINAS ON SAT WHICH WILL ALLOW A SHALLOW N TO NE
FLOW THROUGH 3 KFT TO BE TOPPED BY A DEEP W OR WSW FLOW. THE FLOW
ALOFT IS MARGINALLY MOIST AND THIS ALLOWS PRECIPITABLE WATER
VALUES TO CLIMB TO AROUND THREE-QUARTERS OF AN INCH. THE SYNOPTIC
SETUP DOES ALLOW ISENTROPIC UPGLIDE TO INCREASE AND THE
COMBINATION DOES SUPPORT HIGH POPS. HOWEVER...THE LOWEST 3-5 KFT
DO SHOW INDICATIONS OF HANGING ONTO THE DRY AIR IN THIS RATHER
QUICK HITTING SYSTEM. THEREFORE...WILL FORECAST LIKELY TO
CATEGORICAL POPS AT THIS TIME WITH QPF AMOUNTS ON THE ORDER OF ONE
TENTH TO A QUARTER OF AN INCH. OTHERWISE...FRIDAY WILL SHOW
INCREASING CLOUDS...ESPECIALLY OF THE HIGH VARIETY WITH CLOUDS
LOWERING THROUGH THE AFTERNOON AND EVE. IT WILL BE SOLIDLY CLOUDY
LATER FRI NIGHT AND SAT. CLOUDS MAY BEGIN TO PARTIALLY ERODE FROM
INLAND TO THE COAST SAT NIGHT AS DRIER AIR TRIES TO WORK
IN...ALTHOUGH WE MAY BE LEFT WITH CONSIDERABLE STRATUS FOR MUCH OF
THE NIGHT.

TEMPS ON FRI WILL BE NEAR NORMAL...MID AND UPPER 50S. HOWEVER...
SAT IS SHAPING UP TO BE A CHILLY DAY WITH TEMPS ONLY REACHING THE
UPPER 40S TO LOWER 50S. AN ALL LIQUID EVENT WITH LOWS FRI NIGHT
MAINLY IN THE 40S AND UPPER 30S TO LOWER 40S SAT NIGHT.

&&

.LONG TERM /SUNDAY THROUGH THURSDAY/...
AS OF 300 PM THURSDAY...SUNDAY APPEARS TO BE RAIN-FREE BUT STILL
RATHER CLOUDY WITH NO REAL IMPETUS FOR LOW LEVEL MOISTURE TO BE
ROUTED OUT FOLLOWING THE SATURDAY SYSTEM. THIS MAY CHANGE AS SOON AS
SUNDAY NIGHT HOWEVER AS A VERY WEAK UPPER IMPULSE LEADS TO A LITTLE
CYCLOGENESIS ALONG THE FRONT SITTING OFF THE COAST. FOR A FEW RUNS
NOW THE GFS HAS BEEN QUITE WET LOCALLY WITH THIS SYSTEM AND NOW THE
CMC IS ON BOARD. WILL RAISE POPS BUT NOT GO WITH QUITE THE BULLISH
RAINFALL AMOUNTS SHOWN GIVEN THE WEAK FORCING OVERALL AND TO A
LESSER EXTENT THE BACKING OFF TREND SEEN IN MODELS WITH THE SATURDAY
SYSTEM. ATTENTION THEN TURNS WESTWARD ON TUESDAY AS A DEEP TROUGH
DIGS INTO THE MIDDLE OF THE NATION. THE SURFACE BOUNDARY MAY REACH
THE MOUNTAINS BY EVE BUT LOCALLY THIS SHOULD MEAN ONE DRY DAY.
STRONG DYNAMICS START TO IMPINGE UPON OUR AREA TUESDAY NIGHT AND MAX
OUT WEDNESDAY ALTHOUGH THE FRONT AND DEEP MOISTURE LONG GONE/WELL
OFFSHORE BY MORNING. WEDNESDAY`S COLD AIR ADVECTION MAY BE STRONG
ENOUGH FOR NON-DIURNAL TEMP CURVES AND WED NIGHT THROUGH THURSDAY
NIGHT SHOULD BE RATHER CHILLY.

&&

.AVIATION /06Z FRIDAY THROUGH TUESDAY/...
AS OF 06Z...VFR CONDITIONS WILL PREVAIL AT ALL TERMINALS THROUGH THE
VALID PERIOD. OVERNIGHT...WINDS WILL REMAIN CALM WITH CONTINUED SCT
MID LEVEL CLOUDS INTO THE MORNING HOURS. STILL DO NOT ANTICIPATE ANY
FOG ISSUES GIVEN THE UNFAVORABLE MOISTURE PROFILES AND INCREASING
CLOUDINESS TOWARD DAYBREAK. TODAY...MORE CIRRUS WILL STREAM OVER THE
CAROLINAS WELL AHEAD OF AN UPPER DISTURBANCE. WINDS WILL BECOME N-NE
LESS THAN 10 KT DURING THE DAY. MID LEVEL CLOUDS WILL CONTINUE TO
INCREASE THROUGH THE AFTERNOON HOURS...WITH VFR CIGS 10-15KFT
DEVELOPING FROM WEST TO EAST AFTER 00Z SAT.

EXTENDED OUTLOOK...RAIN LIKELY SAT WITH DEVELOPING MVFR/IFR CIGS
POSSIBLY LASTING INTO SUN. CHANCE OF SHOWERS MON AS LOW PRESSURE
MOVES UP THE COAST. SHOWERS POSSIBLE LATE TUE AHEAD OF A STRONG COLD
FRONT.

&&

.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 12:30 AM FRIDAY...NO CHANGES TO THE FORECAST WITH THE LATEST
UPDATE. PREVIOUS DISCUSSION FOLLOWS:

HIGH PRESSURE OVER THE WESTERN GREAT LAKES WILL MAINTAIN A LIGHT
NORTH WIND ACROSS THE WATERS TONIGHT. WIND SPEEDS SHOULD REMAIN
LESS THAN 10 KNOTS. SEAS ARE 1 TO BARELY 2 FEET CURRENTLY. WAVE
SPECTRA OUT AT THE FRYING PAN SHOALS ARE EVENLY SPLIT BETWEEN 11
SECOND SE SWELL AND 4 SECOND WIND CHOP.

SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/...
AS OF 300 PM THURSDAY...N WINDS FRI WILL VEER TO NNE AND NE FRI
NIGHT WITH NE WINDS PERSISTING THROUGH SAT NIGHT. WIND SPEEDS WILL
BE UP TO 10 TO 15 KT...ESPECIALLY IN THE WAKE OF A SOUTHERN STREAM
SYSTEM SAT NIGHT. SEAS WILL BE 2 FT OR SO INTO FRI NIGHT WITH 3 TO
4 FT SEAS BECOMING MORE COMMON DURING SAT AND ESPECIALLY SAT NIGHT.

LONG TERM /SUNDAY THROUGH TUESDAY/...
AS OF 300 PM THURSDAY...SUNDAY SHOULD BRING A FAIRLY LIGHT GRADIENT
WITH HIGH PRESSURE HOLDING ON TO OUR NORTH AND A WEAK TROUGH OFF THE
COAST. THE OFFSHORE TROUGH WILL CREEP CLOSER TO THE COAST SUNDAY
NIGHT. AS THIS IMPULSE PASSES TO OUR NORTH AN AREA OF EXITING LOW
PRESSURE WILL BE DEVELOPING. NORMALLY THIS WOULD OFFER AN
OPPORTUNITY FOR A BIT OF A SURGE IN WINDS AND SEAS BUT THIS DOES NOT
PAN OUT THIS TIME. FLOW WILL TURN SLIGHTLY OFFSHORE BUT NOT PICK UP
IN SPEED. BACKING WINDS EXPECTED MOST OF TUESDAY AS A FAIRLY STRONG
COLD FRONT APPROACHES FROM THE WEST.

&&

.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...NONE.

&&

$$

SYNOPSIS...RJD
NEAR TERM...REK/TRA
SHORT TERM...RJD
LONG TERM...MBB
AVIATION...BJR
MARINE...REK/RJD/TRA/MBB




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