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000
FXUS62 KILM 191026
AFDILM

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE WILMINGTON NC
626 AM EDT WED JUN 19 2013

.SYNOPSIS...
A COLD FRONT WILL SAG ACROSS THE AREA FROM NORTH TO SOUTH THROUGH
THIS EVENING. THE RISK FOR HEAVY RAINFALL WILL SLOWLY END FROM NORTH
TO SOUTH THROUGH THIS EVENING. HIGH PRESSURE WILL BRING DRIER AIR
INTO THE EASTERN CAROLINAS THURSDAY AND FRIDAY. A WEAK FRONT MAY
MOVE BACK TO THE NORTH OR REDEVELOP OFF THE COAST DURING THE
WEEKEND.

&&

.NEAR TERM /THROUGH TONIGHT/...
AS OF 6 AM WEDNESDAY...A COLD FRONT HAS SLIPPED SOUTH OF A UDG TO
LBT TO EYF LINE. ISOLATED TO SCATTERED SHOWERS WERE MOVING ACROSS
THE FORECAST AREA. THE MOST CONCENTRATED AREA OF SHOWERS AND
THUNDERSTORMS HAS JUST SLIPPED OFF THE CAPE FEAR COAST.

THE COLD FRONT WILL SLOWLY SAG S ACROSS THE REMAINDER OF THE
FORECAST AREA THROUGH THE DAY AND MAY GET HUNG UP FOR A TIME AS THE
MODELS ARE STILL SHOWING WEAK WAVES OF LOW PRESSURE DEVELOPING ALONG
THE FRONT. A RATHER POTENT MID-LEVEL SHORTWAVE WILL PASS LARGELY TO
THE SOUTH OF THE FORECAST AREA TONIGHT AS HIGH PRESSURE TO OUR N
ATTEMPTS TO WEDGE SOUTHWARD ACROSS THE CAROLINAS. WINDS WILL
SHIFT TO THE N AND THEN NE WITH FRONTAL PASSAGE...LASTLY ACROSS
MYRTLE BEACH AND GEORGETOWN LATE DAY AND THIS EVE.

PRECIPITABLE WATER VALUES WILL TOP 2 INCHES TODAY...TRENDING SLOWLY
LOWER DURING THE COURSE OF THE DAY FROM N TO S. THE DRY AIR WILL
BECOME MORE FIRMLY ESTABLISHED INLAND TONIGHT...BUT IT WILL BE MUCH
TOUGHER TO MAKE ANY SIGNIFICANT INROADS ALONG THE COAST. SIGNIFICANT
BREAKS IN THE CLOUD COVER SHOULD DEVELOP INLAND TONIGHT...ESPECIALLY
ACROSS THE NORTHERN PEE DEE THROUGH LBT AND EYF.

THICK CLOUD COVER WILL GREATLY LIMIT THE MAGNITUDE OF INSTABILITY
AND SO NO SEVERE WEATHER IS EXPECTED TODAY. HOWEVER...STORM MOTIONS
WILL BE UNDER 10 KT AND WITH SUCH A MOIST ENVIRONMENT...TORRENTIAL
DOWNPOURS ARE EXPECTED. WILL HIGHLIGHT HEAVY RAIN. WILL INDICATE THE
HIGHEST POPS ALONG AND AHEAD OF THE FRONT WITH POPS SLOWLY TRENDING
LOWER ON THE DRIER SIDE OF THE BOUNDARY. WILL CARRY POPS AS HIGH AS
LIKELY TO CATEGORICAL TODAY. POPS WILL TREND LOWER THROUGH THE
NIGHT...BUT WILL CARRY LIKELY POPS ALONG THE COAST INTO THE EVE. THE
RISK FOR SHOWERS IS EXPECTED TO END FROM NNW TO SSE DURING THE
EVE...WITH ONLY A SMALL RISK ALONG THE COAST AND ALONG THE SOUTH
SANTEE RIVER OVERNIGHT.

HIGH TEMPERATURES SHOULD BE RATHER UNIFORM ACROSS THE AREA...LOWER
TO MID 80S WITH HIGH HUMIDITY LEVELS. DEWPOINTS SHOULD BEGIN TO
LOWER ACROSS N/NW ZONES LATER TODAY AND MORE SO TONIGHT. LOWS
TONIGHT COULD VARY MORE SIGNIFICANTLY GIVEN A DRIER AIRMASS WILL BE
MAKING ITSELF FELT ACROSS PORTIONS OF THE AREA. LOWS SHOULD REACH
THE MID 60S ACROSS MANY INLAND AREAS WITH LOWER 70S HANGING ON
ACROSS PORTIONS OF THE COAST.

&&

.SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
AS OF 3 AM WEDNESDAY...HIGH PRESSURE RIDGES DOWN THE COAST DURING
THE PERIOD WHILE COLD FRONT REMAINS JUST OFF THE COAST. FIRST HALF
OF THE PERIOD SHOULD BE DRY AS WESTERLY FLOW ALOFT IN CONJUNCTION
WITH SLOWLY BUILDING 5H RIDGE HELPS DRY THE REGION OUT. AT THIS
POINT IT LOOKS LIKE THE DEEP MOISTURE ASSOCIATED WITH THE FRONT
REMAINS JUST OFFSHORE AND FORECAST SOUNDINGS DROP PRECIPITABLE
WATER VALUES CLOSE TO 1 INCH LATE THU AFTERNOON. LOW LEVEL
NORTHEAST FLOW WILL PROVIDE SOME LOW LEVEL MOISTURE WHICH IS
LIKELY TO MANIFEST ITSELF AS A SCATTERED TO BROKEN FLAT STRATOCU
DECK IN THE AFTERNOON. CLOUD COVER ALONG WITH THE NORTHEAST FLOW
WILL KEEP HIGHS BELOW CLIMO. CANNOT RULE OUT SOME LIGHT SPRINKLES
NEAR THE COAST FROM ACTIVITY MOVING ON SHORE BUT DEEP DRY AIR
SHOULD PREVENT ANYTHING MEASURABLE.

REINFORCING SHOT OF DRY AIR ARRIVES THU NIGHT BUT IS SHORT LIVED AS
STALLED BOUNDARY MOVES CLOSER TO THE COAST FRI MORNING. LOWS WILL
BE NEAR TO SLIGHTLY BELOW CLIMO THU NIGHT WITH SKIES CLEARING AND
LIGHT NORTHEAST FLOW CONTINUING.

FORECAST SOUNDINGS SHOW A RETURN OF DEEPER MOISTURE DURING THE DAY
FRI AS THE BOUNDARY TRIES TO MOVE ONSHORE. BOUNDARY BECOMES SOMEWHAT
DIFFUSE AT THIS POINT BUT MOISTURE ASSOCIATED WITH IT MOVES ONSHORE
DURING THE AFTERNOON AND EVENING...OPENING UP THE POSSIBILITY OF
SOME ISOLATED CONVECTION. GIVEN THE PROXIMITY TO THE DRY AIR AND THE
WEAK SUBSIDENCE DO NOT THINK COVERAGE WILL BE SIGNIFICANT BUT FEEL
IT DOES WARRANT A SLIGHT CHC POP...MAINLY CONFINED TO COASTAL
COUNTIES. DESPITE CONTINUED NORTHEAST FLOW MORE SUN SHOULD LEAD
TO HIGHS A LITTLE CLOSER TO CLIMO. CLOUD COVER AND LOW LEVEL
MOISTURE ALONG THE COAST WILL CREATE A LARGER SPREAD FOR LOWS FRI
NIGHT. TEMPS WILL RANGE FROM NEAR TO SLIGHTLY ABOVE CLIMO ALONG
THE COAST TO NEAR TO SLIGHTLY BELOW CLIMO WELL INLAND.

&&

.LONG TERM /SATURDAY THROUGH TUESDAY/...
AS OF 3 AM WEDNESDAY...UNCERTAINTY ABOUNDS FOR THE DURATION OF THE
LONG TERM. THE DECENT AGREEMENT SEEN LAST NIGHT HAS EVAPORATED
LEAVING SEVERAL POSSIBLE SOLUTIONS TO PONDER. THESE RANGE FROM
MOSTLY DRY FOR THE WEEKEND AND START OF NEXT WEEK TO VERY WET WITH
POSSIBLE FOR WEAK LOW PRESSURE ALONG THE CAROLINA COAST. COMMON
THEME AMONG THEM IS THE EVOLUTION OF THE MID LEVEL AND SURFACE
PATTERNS AND THE PRESENCE OF LINGER SURFACE BOUNDARY OFF THE
SOUTHEAST COAST. ALL OF THE GUIDANCE SHOW MID LEVEL RIDGE BUILDING
OVER THE SOUTHEAST WHILE AT THE SURFACE BERMUDA HIGH TAKES HOLD.

THE KEY TO THE PERIOD WILL BE HOW DEFINED THE BOUNDARY REMAINS AND
HOW MUCH DEEP MOISTURE LINGERS WHEN THE BOUNDARY COMES ONSHORE AND
THEN LIFTS NORTH. THE ECMWF IS CURRENTLY THE DRIEST AND ALSO THE
SOLUTION WITH THE LEAST AMOUNT OF QUESTIONS CONCERNING ITS VALIDITY.
THE GFS APPEARS TO BE AFFECTED BY FEEDBACK WHICH MAY BE HELPING
MAINTAIN A STRONGER SURFACE BOUNDARY AND DEEPER MOISTURE. THE
CANADIAN DEVELOPS A CLOSED LOW WHICH MAY OR MAY NOT IMPACT THE
CAROLINAS...DEPENDING ON THE RUN. THIS HAS BEEN SOMEWHAT COMMON
FOR THE CANADIAN RECENTLY AS IT HAS BEEN TRYING TO TURN WEAK WAVES
ALONG STALLED COASTAL FRONTS INTO MORE SIGNIFICANT CLOSED LOWS
WITH LITTLE SUCCESS. FOR NOW WILL IGNORE ITS SOLUTION GIVEN
RECENT PERFORMANCES AND THE LACK OF CONSISTENCY. THE RESULT IS
MINIMAL CHANGES TO PREVIOUS FORECAST WITH SLIGHT CHC TO LOW CHC
POP EACH DAY AND TEMPERATURES GRADUALLY INCREASING FROM BELOW
CLIMO TO ABOVE CLIMO BY THE END OF THE PERIOD.

&&

.AVIATION /06Z WEDNESDAY THROUGH SUNDAY/...
AS OF 06Z...HAVE INCLUDED VCSH TO ACCOUNT FOR SHOWERS SLOWLY SAGGING
SOUTH ALONG AND AHEAD OF A COLD FRONT. MVFR/TEMPO IFR CIGS ARE
POSSIBLE THROUGH SUNRISE...THOUGH CONFIDENCE IS LOW ATTM. THE FRONT
IS EXPECTED TO STALL NEAR THE COAST TODAY...AND MORE SHOWERS AND
THUNDERSTORMS APPEAR LIKELY LATER TODAY...ESPECIALLY FOR THE COASTAL
TERMS. WINDS MAY BE LIGHT AND VARIABLE ALONG THE COAST NEAR THE
STALLED BOUNDARY. EXPECT PREVAILING VFR DURING THE DAY WITH TEMPO
MVFR/IFR IN THE HEAVIEST DOWNPOURS. PCPN CHANCES DIMINISH AFTER
00Z...THOUGH SHOWERS COULD LINGER INTO THE EVENING HOURS ALONG THE
COAST.

EXTENDED OUTLOOK...VFR THURSDAY THROUGH SATURDAY. SLIGHT CHANCE OF
SHOWERS ON SUNDAY.

&&

.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 6 AM WEDNESDAY...SHOWERS AND THUNDERSTORMS ARE EXPECTED TO
PRODUCE HEAVY RAIN WHICH WILL LOWER VISIBILITIES TO 1 NM OR LESS AT
TIMES. COVERAGE WILL BE NUMEROUS TO WIDESPREAD AT TIMES INTO TONIGHT.

SW WINDS WILL SHIFT TO N AND THEN NE AS A COLD FRONT SLOWLY SAGS S
ACROSS THE WATERS TODAY. THE NORTHERN WATERS ARE EXPECTED TO SEE THE
WIND SHIFT THIS MORNING THROUGH EARLY AFTERNOON WHILE THE SOUTHERN
WATERS WILL EXPERIENCE THE WIND SHIFT DURING THE LATER AFTERNOON AND
EVE HOURS. A NE SURGE WILL ACTUALLY WORK ITS WAY DOWN THE COAST
OVERNIGHT. THE STRONGEST WINDS WILL OCCUR THIS MORNING AHEAD OF THE
FRONT...MAINLY EARLY AND THEN IN THE NE SURGE OVERNIGHT AND THU
MORNING...UP TO 15 TO 20 KT ACROSS THE NORTHERN WATERS AND NEAR 15
KT ACROSS THE SOUTHERN WATERS. SEAS WILL TREND LOWER THROUGH THE DAY
AND THEN REVERSE HIGHER OVERNIGHT. WILL CAP SEAS AT 5 FT ACROSS THE
NORTHERN WATERS AND 4 FT ACROSS THE SOUTHERN WATERS. WILL HEADLINE
SMALL CRAFT SHOULD EXERCISE CAUTION FOR THE NORTHERN WATERS THIS
MORNING WITH NO HEADLINES FOR THE SOUTHERN WATERS. A HEADLINE MAY
AGAIN BE REQUIRED LATE TONIGHT FOR PORTIONS OF THE WATERS.

SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
AS OF 3 AM WEDNESDAY...PINCHED GRADIENT BETWEEN HIGH PRESSURE
BUILDING SOUTH AND STALLED FRONT OFF THE COAST WILL PRODUCE
NORTHEAST FLOW IN THE 15 TO 20 KT RANGE THU AND THU NIGHT. GRADIENT
STARTS TO WEAKEN LATE THU NIGHT WITH SPEEDS DROPPING TO A SOLID 15
KT BY FRI MORNING. FURTHER REDUCTION IN GRADIENT FRI WILL KEEP
NORTHEAST FLOW IN THE 10 TO 15 KT RANGE. FLOW BECOMES A LITTLE MORE
EASTERLY FRI NIGHT AS SURFACE RIDGE AXIS STARTS TO SETTLE SOUTH.
GRADIENT CONTINUES TO WEAKEN AS REMAINS OF STALLED FRONT LIFT INTO
THE AREA. AS A RESULT SPEEDS WILL DROP BELOW 10 KT BY THE END OF
THE PERIOD. SEAS 3 TO 5 FT THU IN RESPONSE TO STRONG NORTHEAST
FLOW SLOWLY SUBSIDE INTO FRI. GRADUALLY REDUCTION IN WINDS LATE
THU NIGHT AND FRI ALLOWS SEAS TO FALL TO 2 TO 3 FT BY THE END OF
THE PERIOD.

LONG TERM /SATURDAY THROUGH SUNDAY/...
AS OF 3 AM WEDNESDAY...WEAK COASTAL TROUGH IN THE VICINITY AND HIGH
PRESSURE WEAKLY BUILDING DOWN THE COAST DURING THE PERIOD WILL KEEP
WIND LIGHT AND VARIABLE. WINDS WILL BE FROM THE EAST AT 10 KT OR
LESS BUT COULD VARY FROM NORTHEAST TO SOUTHEAST AT ANY GIVEN
TIME...DEPENDING ON THE POSITION OF THE REMAINS OF THE SURFACE
BOUNDARY AND ANY MESOSCALE BOUNDARIES. LIGHT WIND FIELD WILL
MAINTAIN 2 TO 3 FT SEAS WITH HIGHEST SEAS SAT.

&&

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

&&

$$

NEAR TERM...RJD
SHORT TERM...III
LONG TERM...III
AVIATION...BJR/RJD