Area Forecast Discussion
Issued by NWS Wilmington, NC

Current Version | Previous Version | Graphics & Text | Print | Product List | Glossary Off
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50

000
FXUS62 KILM 180252
AFDILM

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE WILMINGTON NC
952 PM EST WED DEC 17 2014

.SYNOPSIS...
HIGH PRESSURE WILL RIDGE INTO THE CAROLINAS THROUGH FRIDAY. LOW
PRESSURE WILL MOVE ALONG THE COAST SATURDAY...BRINGING WIDESPREAD
RAIN AND BELOW NORMAL TEMPERATURES. A DRYING TREND WILL DEVELOP INTO
EARLY NEXT WEEK...ALONG WITH WARMING TEMPERATURES. ANOTHER COLD
FRONT WILL APPROACH LATE TUESDAY.

&&

.NEAR TERM /UNTIL 6 AM THURSDAY MORNING/...
AS OF 930 PM WEDNESDAY... THE SECONDARY COLD FRONT/SURGE LINE HAS
REACHED SOUTHERN VIRGINIA. LATEST HIGH-RES MODELS INDICATE THE
BOUNDARY SHOULD PUSH THROUGH SE NORTH CAROLINA BETWEEN 200-330
AM...AND NE SOUTH CAROLINA BETWEEN 300-600 AM...HERALDED BY A SHIFT
TO NORTH WINDS. INFRARED SATELLITE SHOWS A THIN OVERCAST ACROSS MOST
OF NORTH CAROLINA WITH LESS CLOUDINESS ACROSS SOUTH CAROLINA. A PEEK
UPWARDS FROM THE OFFICE PARKING LOT JUST MINUTES AGO SHOWS PLENTY OF
BRIGHT STARS SHINING THROUGH BUT AN INDISTINCT MILKINESS OBSCURING
THE DIMMER ONES. SKY COVER FORECASTS TRENDING TOWARD PARTLY CLOUDY
ARE PROBABLY THE BEST WAY TO GO FOR THE REST OF THE NIGHT.

DEWPOINTS AT THE COAST HAVE FALLEN BACK INTO THE 30S AND LOWER 40S.
00Z SOUNDINGS FROM MHX AND CHS SHOW TOO STEEP A HYDROLAPSE IN THE
LOWEST COUPLE THOUSAND FEET OF THE ATMOSPHERE FOR SIGNIFICANT
FOG...SO I HAVE REMOVED IT FROM THE FORECAST. LITTLE CHANGE HAS BEEN
MADE TO OVERNIGHT LOW TEMP FORECASTS: LOWS ARE STILL ANTICIPATED TO
REACH 35-40 FOR MOST AREAS BY DAYBREAK. PREVIOUS DISCUSSION FROM 630
PM FOLLOWS...

LIGHT WEST WINDS IN ADVANCE OF A SECONDARY COLD FRONT/SURGE LINE
WILL PROBABLY BECOME CALM HERE AT THE SURFACE IN THE NEXT HOUR. WITH
DEWPOINTS REBOUNDING INTO THE 40S OUTSIDE OF THE SANDHILLS THIS
OPENS THE POTENTIAL FOR FOG DEVELOPING THIS LATER THIS EVENING. A
GRADUAL INCREASE IN CIRRUS CLOUD COVER AND MORE IMPORTANTLY THE
ADVANCING FRONT/SURGE WILL DISTURB THE BOUNDARY LAYER SUFFICIENTLY
AFTER MIDNIGHT TO ERODE ANY FOG THAT DEVELOPS...PROBABLY IN THE 2-4
AM TIMEFRAME. CHANGES WITH THIS NEAR-TERM UPDATE CENTER ON HOURLY
FORECAST TEMPS/DEWPOINTS/WINDS/FOG POTENTIAL. PREVIOUS DISCUSSION
FROM 300 PM FOLLOWS...

THE WEAK CYCLONIC FLOW AROUND POTENT LOW PRESSURE MOVING OFF THE
CANADIAN MARITIMES WILL WEAKEN THROUGH THE AFTERNOON AS A ZONAL MID
LEVEL FLOW PERSISTS. WEAK HIGH PRESSURE WILL BUILD IN FROM THE
NORTHWEST OVERNIGHT WHICH WILL ONLY SERVE TO DAMPEN TEMPERATURES A
BIT THURSDAY. FOR THIS AFTERNOON AND OVERNIGHT...THE ONLY ISSUE IS
HIGH CLOUD COVER STREAMING IN FROM THE SOUTHWEST. THE GFS 200MB RH
FIELDS CAPTURES THIS FAIRLY WELL. I HAVE INCREASED CLOUD COVER A BIT
VERY LATE AS WELL AS ADDING PATCHY FOG AS LIGHT WINDS AND SOME
RADIATIONAL COMPONENT WARRANT. WENT WITH THE COOLER NAM/MET NUMBERS
FOR LOWS.

&&

.SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
AS OF 300 PM WEDNESDAY...QUIET WEATHER FOR MUCH OF THE SHORT TERM
PERIOD WILL COME TO AN END LATE FRI AS POPS FINALLY RETURN TO THE
FORECAST. A WEAK BACK DOOR COLD FRONT WILL DROP SOUTHWARD ACROSS THE
FORECAST AREA ON THU MORNING...THOUGH THERE WILL NOT BE ANY PRECIP
ASSOCIATED WITH THIS FEATURE. SLIGHTLY COOLER AIR WITHIN THE SHALLOW
NORTHERLY FLOW BEHIND THE FRONT WILL KEEP HIGH TEMPS NEAR SEASONABLE
VALUES ON THU AND FRI...GENERALLY MID TO UPPER 50S WITH LOWER 60S
POSSIBLE IN THE PEE DEE REGION. LOWS WILL FALL INTO THE MID 30S
THU NIGHT.

A SOUTHERN STREAM SHORTWAVE WILL MOVE ACROSS TX FRI MORNING AND
CONTINUE RACING ACROSS THE SOUTHEAST DURING THE DAY. THIS WILL HELP
INDUCE CYCLOGENESIS ALONG THE GULF COAST LATE FRI. ALTHOUGH THIS LOW
WILL STAY WELL TO OUR SOUTHWEST DURING THIS SHORT TERM PERIOD...
MOIST OVERRUNNING ALONG THE 300K SURFACE WILL ALLOW LIGHT RAIN TO
SPREAD ACROSS THE AREA FROM SW TO NE OVERNIGHT FRI. LOOKING AT THE
FCST SOUNDINGS...IT WILL TAKE SOME TIME TO OVERCOME THE DRY AIR
BELOW 600 MB EVEN AFTER 06Z SAT. ADDITIONALLY...THE LATEST SREF
PROBS SUGGEST MEASURABLE PRECIP WILL HOLD OFF UNTIL SAT MORNING AT
KILM AND OUR NORTHEAST ZONES. FOR THESE REASONS...WILL TRIM BACK
POPS AND QPF...ESPECIALLY ACROSS THE CAPE FEAR REGION. STILL HAVE
INCLUDED CHC TO LIKELY POPS AT ALL LOCATIONS BY THE END OF THE
PERIOD...BUT MOST OF THE LOCAL IMPACTS FROM THIS SYSTEM WILL BE
CONFINED TO SAT.

&&

.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
AS OF 300 PM WEDNESDAY...DEEP LAYER SATURATION EITHER UNDERWAY OR
JUST ABOUT COMPLETE AT THE START OF THE PERIOD. HIGH PRESSURE WILL
BE CENTERED NORTH OF NEW ENGLAND STATES AND HAVE A RIDGE AXIS
EXTENDING ALL THE WAY DOWN INTO THE CAROLINAS. A SURFACE AND LOW
LEVEL LOW WILL MEANWHILE BE TRAVERSING THE GULF STATES/FLORIDA
PANHANDLE AREA. THIS LEADS TO FAIRLY DEEP BUT ALSO SOMEWHAT GENTLE
ISENTROPIC UPGLIDE. IT`LL BE INTERESTING TO SEE HOW MUCH RAIN THIS
YIELDS WHEN ALL IS SAID AND DONE AS HINTED AT BY SOME DIFFERING
MODEL OPINIONS. THE WRF SHOWS A FAIRLY EVEN DISTRIBUTION OF
PRECIPITATION AT LEAST THROUGH ITS MAIN 84 HOUR FCST WINDOW TO SAT
EVE. THE GFS ON THE OTHER HAND IS SUPPRESSING HIGHEST QPF OVER SRN
ZONES...WHICH MAY BE IN DEFERENCE TO THE DRY AIR BEING SUPPLIED BY
THE SFC WEDGE. THE CMC LARGELY AGREES WITH THIS OPINION AND SO THE
FORECAST HAS BEEN MINORLY TWEAKED ACCORDINGLY. BY EVENING THE DEPTH
OF THE MOISTURE WILL BE ON THE WANE AND THE UPGLIDE PRETTY MUCH
SHUTS OFF. LOW LEVEL MOISTURE LINGERS SAT NIGHT INTO SUNDAY IN ASSOC
WITH THE CONTINUED WEDGING, THIS MOISTURE TRAPPED UNDER AN INVERSION
AS THE SURFACE LOW SKIRTS OFF TO THE NORTH AND EAST FAIRLY QUICKLY.
BY MONDAY THE WEDGE APPEARS TO HAVE WASHED OUT WHICH MAY ALLOW FOR
THE LOW LEVEL MOISTURE TO MIX MORE DEEPLY LOWERING THE OVERALL
RELATIVE HUMIDITY BY ENTRAINING DRY AIR FROM ABOVE...I.E. SUNSHINE
SHOULD RETURN. MOISTURE AND WARM ADVECTION UNDERWAY ON TUESDAY AS
NEXT DEEP TROUGH GETS DUG OUT, THIS ONE FURTHER WEST. THIS SYSTEM
SHOULD BRING SHOWERS TUESDAY NIGHT INTO WEDNESDAY, THUNDERSTORMS
APPEAR POSSIBLE AND MAY BE STRONG IF THE FAIRLY POTENT LOOKING GFS
SOLUTION COMES TO PASS.

&&

.AVIATION /00Z THURSDAY THROUGH MONDAY/...
AS OF 00Z...VFR AT THE TERMINALS THIS EVENING WITH CALM/LGT SW
WINDS. WINDS WILL BECOME LGT NW-N ALL TERMINALS OVERNIGHT. THERE IS
A CHANCE PATCHY BR WILL DEVELOP IN THE PRE-DAWN HOURS WITH TEMPO
MVFR VSBYS POSSIBLE. SOUNDINGS DO NOT SUPPORT DENSE FOG. VFR
EXPECTED AFTER SUNRISE WITH N-NE WINDS BECOMING LGT E IN THE LATE
AFTERNOON.

EXTENDED OUTLOOK...VFR THROUGH FRIDAY. GOOD CHANCE OF RAIN ON
SATURDAY WITH POSSIBLE MVFR/IFR CONDITIONS. A SLIGHT CHANCE OF
PRECIP ON SUN AND MON.

&&

.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 930 PM WEDNESDAY...WINDS ARE VEERING MORE WESTERLY...ALBEIT
MORE SLOWLY THAN I ANTICIPATED ALONG THE SC COAST. THE FRONT/SURGE
LINE IS DROPPING SOUTH ACROSS SOUTHERN VIRGINIA CURRENTLY...WITH THE
23Z HIGH-RES MODEL RUNS SHOWING A 3-6 AM TIMING FOR THE WIND SHIFT
FROM CAPE FEAR DOWN TO WINYAH BAY. SEAS CONTINUE AROUND 2 FEET WITH
THE BULK OF THE WAVE ENERGY IN A 10 SECOND SE SWELL.

SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
AS OF 300 PM WEDNESDAY...EXPECT NORTH WINDS AROUND 10 KT DURING THE
DAY THU BEHIND A WEAK COLD FRONT. SEAS WILL REMAIN AROUND 2 FT THU
THROUGH MUCH OF FRI AS THE GRADIENT REMAINS FAIRLY RELAXED OVER THE
WATERS. A SURFACE LOW WILL BEGIN TO TAKE SHAPE ALONG THE GULF COAST
LATE FRI...AND IN RESPONSE THE GRADIENT OVER THE WATERS WILL TIGHTEN
BETWEEN THIS LOW AND HIGH PRESSURE BUILDING DOWN FROM THE NORTH.
WINDS FRI NIGHT WILL BECOME NORTHEAST 10 TO 15 KT...AND SEAS WILL
BUILD TO 3 FT WITH A DOMINANT NE WIND CHOP AND A WEAK BACKGROUND
SE SWELL.

LONG TERM /SATURDAY THROUGH MONDAY/...
AS OF 300 PM WEDNESDAY...ALTHOUGH NOT A BANNER DAY FOR SAILING DUE
TO WIDESPREAD RAIN NO ADVISORY OR HEADLINES EXPECTED ON SATURDAY IN
A WEATHER SITUATION THAT CAN SOMETIMES YIELD EITHER. HIGH PRESSURE
WEDGING IN FROM THE NORTH WHILE STORM SYSTEM STRENGTHENS SLOWLY AND
MOVES FROM THE GULF STATES INTO THE FLORIDA PANHANDLE. AS THE LOW
BEGINS TO EXIT TO THE NORTH AND EAST WINDS WILL BACK IN DIRECTION
WITH LITTLE EFFECT ON SEAS SAVE A SMALL INCREASE IN THE BRUNSWICK
COUNTY NEARSHORE WAVE SHADOW. HEADING INTO MONDAY BRINGS A WEAKENING
OF THE OVERLAND HIGH PRESSURE AND THUS A WIND THAT TURNS A BIT
OFFSHORE AND WEAKENS CONSIDERABLY, LIKELY DROPPING TO 10KT OR LESS.

&&

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

&&

$$

NEAR TERM...TRA
SHORT TERM...BJR
LONG TERM...MBB
AVIATION...MRR





USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.