Area Forecast Discussion
Issued by NWS Wilmington, NC

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000
FXUS62 KILM 020543
AFDILM

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE WILMINGTON NC
140 AM EDT TUE SEP 2 2014

.SYNOPSIS...
SUMMERTIME CONDITIONS WILL PERSIST MUCH OF THE WEEK AS BERMUDA
HIGH PRESSURE REMAINS ANCHORED OFF THE COAST. THUNDERSTORMS WILL
BE POSSIBLE EACH DAY. A WEAK FRONT WILL STALL IN THE AREA MID TO
LATE WEEK...BRINGING AN INCREASE IN RAIN CHANCES. A STRONGER COLD
FRONT MAY BRING UNSETTLED WEATHER NEXT WEEKEND.

&&

.NEAR TERM /THROUGH TONIGHT/...
AS OF 140 AM TUESDAY...ALL CONVECTION HAS DISSIPATED. CONVECTIVE
CLOUD DEBRIS WILL CONTINUE TO SLOWLY THIN OVERNIGHT. ANOTHER
MODEST NOCTURNAL JET LATE TONIGHT SHOULD HELP TO KEEP THE BOUNDARY
LAYER FROM FULLY DECOUPLING WITH AT LEAST A LIGHT BREEZE FROM TIME
TO TIME...ESPECIALLY AT THE COAST WHERE MIXING WILL BE LEAST
INHIBITED. GIVEN THE MOISTURE IN THE LOWEST LEVELS...WILL INCLUDE
SOME PATCHY FOG...ALTHOUGH WOULD EXPECT SOME STRATUS TO DEVELOP
BELOW 500 FT.

AS HAS BEEN THE CASE THE LAST COUPLE OF NIGHTS...SHOWERS OFFSHORE
MAY SKIRT THE COAST LATE AS A LANDBREEZE DEVELOPS AND MOVES OFFSHORE.
GIVEN THE SW FLOW...THE RISK FOR A BRIEF SHOWER BEFORE DAYBREAK
SHOULD BE HIGHEST AROUND BALD HEAD ISLAND...BUT THE VAST MAJORITY OF
SHOWERS SHOULD STAY OFFSHORE.

LOW TEMPS WILL BE SIMILAR TO THE LAST FEW DAYS...LOWER TO MID 70S
BUT CLOSER TO 80 DEG ON THE OCEANFRONT.

&&

.SHORT TERM /WEDNESDAY THROUGH WEDNESDAY NIGHT/...
AS OF 230 PM MONDAY...TYPICAL SUMMERTIME PATTERN CONTINUES WITH HIGH
PRESSURE ANCHORED OVER THE WESTERN ATLANTIC KEEPING UP A STEADY WARM
AND MOIST SOUTHERLY FLOW THROUGH THE NEAR TERM. DIURNAL CONVECTION
POSSIBLE BOTH DAYS BUT EXPECT GREATER COVERAGE ON WEDNESDAY AS
DEEPER MOISTURE ADVECTS IN AND AN UPPER DISTURBANCE TRANSITS
OVERHEAD. TIMING OF THIS FEATURE NOT CERTAIN AT THIS TIME...BUT IF
IT COINCIDES WITH PEAK HEATING WE COULD SEE GREATER POPS THAN THE 40
PERCENT CURRENTLY ADVERTISED. A WEAK FRONT WILL STALL JUST NORTH OF
THE FORECAST AREA ON WEDNESDAY AND IS NOT EXPECTED TO BE A PLAYER IN
THIS FORECAST. HOWEVER...THE PIEDMONT TROUGH AND SEA BREEZE BOUNDARY
WILL BE FOCI FOR CONVECTION ON BOTH DAYS.

MODEL CONSENSUS HAS DAYTIME TEMPERATURES A BIT ABOVE NORMAL ON
TUESDAY WITH LOWER TO MID 90S MOST PLACES. INCREASED CLOUD COVER
WILL KNOCK A FEW DEGREES OFF THAT ON WEDNESDAY...WITH HIGHS A BIT
MORE SEASONAL...RANGING FROM THE UPPER 80S TO LOWER 90S. CONTINUED
WARM SOUTHERLY FLOW WILL KEEP OVERNIGHT TEMPERATURES A TAD ABOVE
NORMAL BOTH DAYS...WITH LOWS IN THE LOWER TO MID 70S MOST PLACES.

&&

.LONG TERM /THURSDAY THROUGH MONDAY/...
AS OF 230 PM MONDAY...TRAILING SEGMENT OF FRONT EXTENDING FROM NORTH
CAROLINA OUT TO THE E-NE INTO THE ATLANTIC SHOULD ACT AS FOCUS OF
CONVECTIVE DEVELOPMENT ON THURS ALONG WITH PIEDMONT TROUGH AND SEA
BREEZE BOUNDARY. ALTHOUGH MOST OF THE ACTIVITY ASSOCIATED WITH FRONT
SHOULD REMAIN NORTH OF LOCAL FORECAST AREA WITH A PRONOUNCED
SOUTHERLY LOW LEVEL FLOW...THE WINDS IN THE MID TO UPPER LEVELS WILL
BE MORE N-NE ON EASTERN EXTENT OF RIDGE OVER THE SOUTHERN CONUS AND
SHOULD DRAG MOISTURE SOUTH. THE PCP WATER VALUES REACH UP TO 2
INCHES OVER SOUTHEAST NORTH CAROLINA. THE MOISTURE PROFILES SHOW
THIS NICELY WITH HIGH RH VALUES LOCKED IN ABOVE H5. THEREFORE EXPECT
PLENTY OF MID TO HIGH CLOUDS BUT SOME CONVECTIVE DEVELOPMENT PUSHING
SOUTH INTO NORTHERN TIER OF FORECAST AREA. WILL KEEP GREATEST POPS
OVER NORTH CAROLINA ZONES ON THURS.

BY FRI A RIDGE OF HIGH PRESSURE SHIFTING OFF THE MID ATLANTIC COAST
WILL PRODUCE A DEEPER SOUTHERLY FLOW OVER THE COASTAL CAROLINAS. ANY
REMNANTS OF LINGERING FRONT OVER NORTH CAROLINA SHOULD RETREAT NORTH
AND DISSIPATE LEAVING SEA BREEZE AND PIEDMONT TROUGH AS FOCAL POINTS
FOR CONVECTION ON FRI IN A CONTINUED WARM AND HUMID AIR MASS.
THEREFORE MOST ACTIVITY SHOULD REMAIN WEST AND NORTH OF AREA.

A DEEPENING TROUGH MOVING EAST OVER THE GREAT LAKES OVER THE WEEKEND
SHOULD PUSH A COLD FRONT INTO THE CAROLINAS SAT NIGHT INTO SUN.
THEREFORE EXPECT MORE WIDESPREAD CONVECTION THE LATTER HALF OF THE
WEEKEND AS FRONT MOVES INTO THE CAROLINAS. GFS SHOWS HIGH PRESSURE
BUILDING DOWN BEHIND FRONT MON INTO TUES WITH A CHANGE IN AIR MASS
LEADING TO TO DRIER AND RELATIVELY COOLER WEATHER. BUT ECMWF HOLDS
FRONT TO OUR NORTH WITH MORE UNSETTLED WEATHER AND WARM AND MOIST
SOUTHERLY FLOW HOLDING ON FOR MONDAY. WILL HAVE TO WAIT FOR FUTURE
MODEL RUNS TO RESOLVE THIS. FOR NOW WILL KEEP LOWER END POPS FOR
MONDAY.

WILL MAINTAIN WARM AND HUMID AIR MASS THROUGH THE PERIOD WITH MAX
TEMPS UP AROUND 90 OR SO AND OVERNIGHT LOWS HOLDING UP AROUND 70
OR SO. SHOULD SEE TEMPS LOWER BY END OF WEEKEND IN INCREASED CLOUD
COVER AND CONVECTION AND MAY SEE LOWER TEMPS FOR MON INTO TUES IF
FRONT MOVES SOUTH OF AREA.

&&

.AVIATION /06Z TUESDAY THROUGH SATURDAY/...
AS OF 06Z...VFR CONDITIONS TONIGHT MAY GIVE WAY TO PATCHY AREAS OF
MVFR/IFR CIGS EARLY THIS MORNING. LAMP GUIDANCE AND FCST SOUNDINGS
INDICATE KFLO/KLBT HAVE THE BEST CHANCES OF SEEING TEMPO IFR/LIFR
CIGS DEVELOP JUST AFTER DAYBREAK. GIVEN EXTENSIVE DEBRIS CLOUDINESS
AND NOCTURNAL LOW LEVEL JETTING...FOG SEEMS LESS LIKELY THAN LAST
NIGHT...SO WILL JUST INCLUDE MVFR VSBYS FOR THE INLAND TERMS. ALONG
THE COAST...HAVE INCLUDED TEMPO MVFR CIGS AS 1-2KFT CLOUDS MAY CLIP
THESE SITES DURING THE EARLY MORNING HOURS. LIGHT SOUTHWEST FLOW
SHOULD KEEP SHOWER ACTIVITY OFFSHORE...SO NO VCSH FOR THE COASTAL
TERMS ATTM. VFR WILL PREVAIL DURING THE DAY AS SOUTHWEST WINDS
AROUND 5 KT BECOME SOUTH AROUND 10 KT IN THE AFTN BEHIND THE SEA
BREEZE. WE COULD SEE INCREASED SHOWER/TSTM ACTIVITY AFTER MIDDAY AS
SOUNDINGS DO SHOW DEEPER MOISTURE AVAILABLE. BUT WILL HOLD OFF ON
INCLUDING VCSH SINCE COVERAGE WOULD LIKELY BE ISO/SCT AT BEST.

EXTENDED OUTLOOK...CHANCE OF SCATTERED AFTN SHOWERS/TSTMS THROUGH
FRIDAY. PATCHES OF MVFR/IFR FOG OR STRATUS MAY ALSO DEVELOP EACH
MORNING. BUT OVERALL VFR CONDITIONS SHOULD PREVAIL.

&&

.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 1000 PM MONDAY...MODEST NOCTURNAL JETTING SHOULD KEEP WINDS
THROUGH THE NIGHT IN THE RANGE OF 10 TO 15 KT WITH GUSTS TO AROUND
20 KT. SOUTHWEST WINDS SHOULD VEER A FEW DEGREES AS THE LANDBREEZE
PUSHES OUT ACROSS THE WATERS LATE. SEAS WILL BE MAINLY 3 FT WITH
PERHAPS SOME 4 FT SEAS ACROSS PORTIONS OF THE OUTER MOST WATERS.

SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/...
AS OF 230 PM MONDAY...HIGH PRESSURE OVER THE WESTERN ATLANTIC WILL
MAINTAIN A SOUTHWEST FLOW ACROSS THE WATERS THROUGH THE SHORT TERM.
WINDS WILL BE GENERALLY IN THE 10 TO 15 KT RANGE...ON THE HIGHER END
OF THIS RANGE DURING THE DAYTIME AND ESPECIALLY NEAR THE COAST AS
THE DIURNAL SEA BREEZE CIRCULATION SETS UP. WEAKER GRADIENT AT NIGHT
WILL KEEP WINDS CLOSER TO 10 KTS. SEAS WILL RANGE FROM 2 TO 3 FT
THROUGH THE PERIOD.

LONG TERM /THURSDAY THROUGH SATURDAY/...
AS OF 230 PM MONDAY...SHOULD CONTINUE TO SEE SOUTHERLY RETURN FLOW
THURS THROUGH SATURDAY AROUND BERMUDA HIGH. GRADIENT WILL REMAIN
FAIRLY WEAK WITH SEA/LAND BREEZE DOMINATING THE FLOW AS WELL AS
ENHANCEMENT DUE TO PIEDMONT TROUGH. WINDS WILL SPIKE UP EACH
AFTERNOON NEAR SHORE AS SEA BREEZE STRENGTHENS. SEAS WILL REMAIN
FAIRLY BENIGN WITH HEIGHTS LESS THAN 3 FT AND SLIGHT CHOP IN THE
AFTN SEA BREEZE. BY LATE SATURDAY...A FRONT SHOULD REACH INTO THE
CAROLINAS LEADING TO A TIGHTENING OF GRADIENT AND INCREASE IN S-SW
FLOW LEADING TO A SLIGHT RISE IN SEAS.

&&

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

&&

$$

NEAR TERM...RJD/8
SHORT TERM...REK
LONG TERM...RGZ
AVIATION...BJR/8








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