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-- Discussion containing changed information from previous version are highlighted. --
000
FXUS62 KILM 200313
AFDILM

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE WILMINGTON NC
1113 PM EDT WED JUN 19 2013

.SYNOPSIS...
AS THE COLD FRONT SAGS FARTHER SOUTH THROUGH THIS EVENING...THE
RISK OF RAIN WILL SLOWLY END FROM NORTH TO SOUTH. THIS FRONT WILL
LINGER SOUTH OF COASTAL NORTH CAROLINA AS HIGH PRESSURE NOSES IN
FROM THE NORTH...PUSHING SOME DRIER AIR ACROSS THE REGION LATE
TONIGHT THROUGH THURSDAY. THE LINGERING FRONT WILL NUDGE BACK TO
THE NORTH FRIDAY INTO THIS WEEKEND...ACCOMPANIED BY INCREASING
CLOUDS AND CHANCE FOR CONVECTION MAINLY ACROSS THE COASTAL
CAROLINAS.

&&

.NEAR TERM /THROUGH THURSDAY/...
-- Changed Discussion --
AS OF 1045 PM WEDNESDAY...CURRENT PCPN AND LATEST HRRR INDICATE POPS
WILL CONTINUE TO DROP ACROSS THE REGION LATE THIS EVENING AND
OVERNIGHT...AND TRANSITION TO A MORE STRATIFORM TYPE PCPN. IN
FACT...LATEST 88D AND SFC OBS INDICATE LOW LEVEL -SHRA OR -RA
AND DRIZZLE WITHIN THE LOW LEVEL NE-E FLOW BEGINNING TO DOMINATE
PCPN ACROSS THE IMMEDIATE COAST AND SOUTHERN PORTIONS OF THE ILM
CWA INTO THE PRE-DAWN THU HOURS. WILL CONTINUE TO USE THE LATEST
HRRR MODEL TO ILLUSTRATE THE CURRENT AND PROGGED LOCATION OF THE
FRONT...AND THE SENSIBLE WX PARAMETERS IN THE WAKE OF THE COLD
FRONT.

LOOKING AT THE LATEST SAT IMAGERY...DO NOT SEE THE CLEARING BEHIND
THE FRONT THAT MODELS TRY TO INFILTRATE ACROSS THE FA OVERNITE.
HOWEVER...THE CLOUDS WEST OF I-95 ARE OF THE HIGH LEVEL VARIETY.
AS A RESULT...HAVE BACKED DOWN WITH THE OPAQUE CLOUDINESS
ESPECIALLY INLAND. HOWEVER...IT CAN EASILY FILL BACK IN WITH LOW
LEVEL STRATUS. HAVE ONLY INCLUDED PATCHY FOG AT THIS
POINT...ANYTHING WORSE WILL HAVE TO BE MONITORED SINCE FOG NOT A
COMMON OCCURRENCE OUTSIDE OF PCPN DURING THIS TIME OF THE YEAR.
WILL KEEP MIN TEMPS IN THE 65 TO 70 DEGREE RANGE...WHERE LOWER
READINGS TO OCCUR WELL INLAND.
-- End Changed Discussion --

&&

.SHORT TERM /THURSDAY NIGHT THROUGH FRIDAY NIGHT/...
AS OF 300 PM WEDNESDAY...LATEST MODEL RUNS HEDGING TOWARD A
CLOUDIER AND WETTER FORECAST FOR THE COASTAL AREAS AS FRONT
LINGERS NEAR OR JUST SOUTH OF AREA THROUGH THE PERIOD AND THEN
MOVES BACK NORTH AND WEST. ALTHOUGH HIGH PRESSURE TRIES TO BUILD
DOWN FROM THE NORTH...IT LOOKS LIKE THE RIDGE TO THE SOUTH WILL
END UP PUSHING THE DIFFUSE BOUNDARY AND ASSOCIATED MOISTURE BACK
NORTH. THE HIGH PRESSURE TO THE NORTH WILL CONTINUE TO NOSE DOWN
INTO THE INLAND PORTIONS OF THE CAROLINAS BUT THERE WILL BE A
TIGHT GRADIENT BETWEEN THE TWO AIR MASSES...SLIGHTLY COOLER AND
MUCH DRIER TO THE NORTHWEST AND MUCH WETTER TO THE SOUTHEAST. THE
BIG QUESTION IS WHERE WILL THIS DIVIDING LINE END UP. PREVIOUS
MODEL RUNS KEPT OUR AREA IN THE DRIER AIR BUT LATEST RUNS ARE
TRENDING TO A WETTER FORECAST...MAINLY ALONG THE COAST. PCP WATER
VALUES WILL BE AS LOW AS ONE INCH BASICALLY WEST OF I95 AND UP TO
1.75 INCHES OR GREATER OVER NORTHEAST SOUTH CAROLINA COAST.

LOOKS LIKE OUR BEST CHC FOR DRIER NICER WEATHER WILL BE ON THURS
BEFORE BOUNDARY MAKES ITS PUSH NORTH. FOR NOW WILL KEEP ANY CHC OF
PCP JUST ALONG THE COAST AND PRIMARILY OVER COASTAL SOUTH
CAROLINA...BUT MAY END UP BEING A GOOD DEAL OF CLOUDS OVER MUCH OF
THE AREA EXCEPT INLAND COUNTIES...MAINLY WEST OF I95 WHERE DRIER
AND SUNNIER WEATHER SHOULD BE. BASICALLY ANY SHIFT IN THIS
BOUNDARY WILL CHANGE FORECAST QUITE A BIT AND THEREFORE MUCH
UNCERTAINTY EXISTS FOR FORECAST ACROSS THE COASTAL COUNTIES.

PCP ALONG THE COAST...CLOUDS AND NORTHEAST FLOW WILL KEEP TEMPS
BELOW NORMAL. TEMPS SHOULD REMAIN CLOSER TO 80 ALONG THE COAST TO
MID 80S INLAND. OVERNIGHT LOWS SHOULD BE IN THE MID 60S.

&&

.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
AS OF 300 PM WEDNESDAY...SOME UNCERTAINTY REMAINS IN THE
EXTENDED...BUT GUIDANCE IN DECENT AGREEMENT FOR THE MOST PART IN A
DEVELOPING TYPICAL SUMMERTIME PATTERN...WITH RIDGING AT 500MB AND A
BERMUDA HIGH SITTING OFFSHORE. DURING NEXT WEEK...HIGH PRESSURE
OFFSHORE WILL COMBINE WITH BUILDING 1000-500MB THICKNESSES TO CREATE
A WARMING TREND...WITH TEMPS RISING TO ABOVE NORMAL..AND WIDESPREAD
90S ARE LIKELY EARLY NEXT WEEK. AT THE SAME TIME...THIS PATTERN
TYPICALLY SUPPORTS SCATTERED AFTN CONVECTION...AND NEXT WEEK SHOULD
BE NO DIFFERENT. WITHOUT ANY MEANINGFUL CAP...AND PWATS RISING TO
NEAR TWO INCHES...HAVE CHC/SCHC CONVECTION EACH AFTN...WANING
NOCTURNALLY.

THE BIGGEST QUESTION MARK IN THE EXTENDED THEN IS THE FIRST PORTION
OF THE PERIOD. COLD FRONT OFFSHORE WILL BE WEAKENING...AND AS HIGH
PRESSURE BUILDS WELL EAST...SYNOPTIC RETURN FLOW WILL PUSH THIS
BOUNDARY BACK TOWARDS THE COAST DURING SATURDAY...LIFTING NORTH OF
THE AREA ON SUNDAY. QUESTION MARKS REMAIN AS TO HOW STRONG THIS
BOUNDARY WILL BE...HOW MUCH MOISTURE WILL STILL BE ASSOCIATED WITH
IT...AND WHETHER A LOW PRESSURE WILL DEVELOP ALONG IT. ATTM WILL
CONTINUE TO SUPPORT THE ECMWF WHICH HAS BEEN THE MOST
CONSISTENT...BUT MAY BE A BIT DRY...AND WILL NOT INCLUDE ANY MENTION
OF LOW PRESSURE DEVELOPMENT...BUT WILL SUPPORT CHC POP SAT INTO SUN
AS THE TROUGH PUSHES ONSHORE. TEMPS WILL BE HINDERED DURING THE WKND
BY CLOUDS AND PRECIP...AND EXPECT LOW/MID 80S SAT BEFORE WARMING AS
SOME COLUMN DRYING OCCURS ON SUNDAY.

&&

.AVIATION /03Z THURSDAY THROUGH MONDAY/...
AS OF 00Z...A COLD FRONT REMAINS JUST SOUTH OF OUR CWA THIS
EVENING...WITH SHOWERS/T-STORMS DEVELOPING ALONG THE FRONT MOVING
OFFSHORE. WILL KEEP VCSH FOR KMYR/KCRE THRU THE EVENING HOURS...
ALTHOUGH THE DRIER AIR BEHIND THE FRONT LIKELY WILL LIMIT ANY PCPN
IN THE FCST AREA. GUIDANCE AND FCST SOUNDINGS SUPPORT MVFR/IFR CIGS
DEVELOPING AT ALL TERMS AFTER 06Z...SLIGHTLY FAVORING THE INLAND
SITES. BEST CHANCES FOR IFR APPEAR TO BE FROM 09-12Z ATTM. MVFR CIGS
COULD LINGER THRU THE MORNING HOURS...ESPECIALLY ALONG THE COAST...
BEFORE DRYING OUT IN THE AFTN AS HIGH PRESSURE INCHES DOWN FROM THE
NORTH. E/NE WINDS WILL STRENGTHEN TO 10-15 KTS DURING THE DAY AS THE
SFC PRESSURE GRADIENT TIGHTENS OVER THE CAROLINAS.

EXTENDED OUTLOOK...SLIGHT CHANCE OF SHOWERS FRIDAY THRU SUNDAY AS A
STALLED FRONTAL BOUNDARY LINGERS NEAR THE COAST. VFR ON MONDAY.

&&

.MARINE...
-- Changed Discussion --
NEAR TERM /THROUGH TONIGHT/...
AS OF 1045 PM WEDNESDAY...AS MENTIONED BY THE PRIOR FORECASTER...
ONLY A FEW MODELS ARE HANDLING THE CURRENT LOCATION OF THE COLD
FRONT AND ITS SOUTHWARD MOVEMENT. WILL STALL IT SOUTH AND WELL
EAST AND OFFSHORE FROM THE ILM COASTAL WATERS BY DAYBREAK
THU...PER LATEST HRRR GUIDANCE. LOOK FOR THE SFC PG TO TIGHTEN
ACROSS THE AREA WATERS AS THE HIGH FLEXES SOUTHWARD OVERNIGHT INTO
THURSDAY. HAVE STAYED CLOSER TO THE HRRR OUTPUT WITH A SOLID 15 KT
AFTER MIDNIGHT WITH GUSTS UP TO 20 KT.

THE LATEST RUN OF LOCALLY PRODUCED SWAN HAS FINALLY COME CLOSER TO
CURRENT SEA CONDITIONS...AND WILL THEREFORE USE ITS OUTPUT FOR
THE OVERNIGHT INTO THURSDAY PERIOD. THE WIND DRIVEN 4 TO 6 SECOND
PERIOD WAVES WILL DOMINATE THE SIGNIFICANT SEAS OVERNIGHT INTO THU.

SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
AS OF 300 PM WEDNESDAY...HIGH PRESSURE WILL BUILD IN BEHIND FRONT
WHICH WILL SLOWLY SAG SOUTH INITIALLY AND THEN BACK NORTH BY
FRIDAY. THE PINCHED GRADIENT BETWEEN THE HIGH PRESSURE BUILDING
SOUTH AND STALLED FRONT OFF THE COAST WILL PRODUCE PERSISTENT
NORTHEAST WINDS AROUND 15 KT THURSDAY. THIS IN TURN WILL PRODUCE
SEAS IN THE 3 TO 5 FT RANGE MOST WATERS...BUT LOWER JUST SOUTH OF
CAPE FEAR WHICH REMAINS BLOCKED FROM NORTHEAST WINDS.

GRADIENT WILL RELAX A BIT LATE THURS INTO FRI WITH WINDS SUBSIDING
TO 10 TO 15 KTS THURS NIGHT AND CLOSER TO 10 KTS BY FRI. THIS WILL
ALLOW SEAS TO DROP DOWN TO 2 TO 4 FT. WINDS VEER AROUND AS
BOUNDARY LIFTS NORTH BECOMING MORE EAST TO SOUTHEAST THROUGH
FRIDAY ON EAST SIDE OF BOUNDARY. WINDS WILL REMAIN NORTHEAST 10
KTS OR LESS ON WEST SIDE OF LINGERING FRONT AND MORE SOUTHERLY UP
TO 15 KTS ON EAST SIDE OF BOUNDARY WHICH MAY INTERSECT RIGHT
THROUGH OUR LOCAL WATERS ON FRIDAY.

LONG TERM /SATURDAY THROUGH MONDAY/...
AS OF 300 PM WEDNESDAY...LIGHT NE WINDS SATURDAY WILL GRADUALLY TURN
TO THE SE AS COASTAL TROUGH/REMNANT FRONT PUSHES WEST ONSHORE DURING
THE DAY. THIS IS IN RESPONSE TO A BERMUDA HIGH PRESSURE BUILDING
ACROSS THE WESTERN ATLANTIC OCEAN...WHICH WILL THEN CONTROL THE
SYNOPTIC ENVIRONMENT THROUGH THE REMAINDER OF THE
EXTENDED...CREATING SW WINDS AROUND 10 KTS OVER THE WATERS. WITH THE
GRADIENT REMAINING RELATIVELY WEAK...WIND WAVE CONTRIBUTION TO THE
SPECTRUM WILL BE ONLY MINIMAL...AND THE COMBINATION OF WIND WAVES
(NE ON SATURDAY...SE SUN/MON) AND A GROWING SE SWELL WILL CREATE 2-4
FT SEAS THROUGH THE PERIOD.
-- End Changed Discussion --

&&

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

&&

$$
SYNOPSIS...RGZ
NEAR TERM...DCH
SHORT TERM...RGZ
LONG TERM...JDW
AVIATION...BJR