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000
FXUS62 KILM 150545
AFDILM

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE WILMINGTON NC
145 AM EDT WED MAY 15 2013

.SYNOPSIS...
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WARMER TEMPERATURES WILL DEVELOP TODAY AND SHOULD CONTINUE THROUGH
EARLY NEXT WEEK AS HIGH PRESSURE PUSHES OFFSHORE. ISOLATED
THUNDERSTORMS WILL BECOME POSSIBLE BEGINNING ON FRIDAY.
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&&

.NEAR TERM /UNTIL 6 AM THIS MORNING/...
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AS OF 1:30 AM WEDNESDAY...NO CHANGES TO THE FORECAST WITH THE
LATEST UPDATE. PREVIOUS DISCUSSIONS FOLLOW:

I HAVE RAISED FORECAST LOWS ANOTHER DEGREE OR TWO ALONG THE
BRUNSWICK COUNTY COASTLINE WHERE STRENGTHENING SOUTHWEST WINDS
SHOULD KEEP THE FAIRLY WARM MARINE AIRMASS IN PLACE THROUGH THE
NIGHT. LOW TEMPERATURES FOR OAK ISLAND TO BALD HEAD ISLAND SHOULD
STAY IN THE 60S OVERNIGHT. THIS EFFECT MAY ONLY IMPACT THE BARRIER
ISLANDS AND A SHORT DISTANCE INLAND HOWEVER...SO FEW CHANGES HAVE
BEEN MADE MORE THAN ABOUT 2-3 MILES INLAND FROM THE BEACHES/CAPE
FEAR RIVER. PREVIOUS DISCUSSION FROM 730 PM FOLLOWS...

AIRMASSES WILL CHANGE IN A HURRY OVERHEAD TONIGHT...WITH MUCH WARMER
TEMPERATURES ANTICIPATED TOMORROW. SURFACE HIGH PRESSURE CENTERED
NOT QUITE 200 MILES SE OF CAPE FEAR WILL RETREAT OFFSHORE
TONIGHT...WITH A TIGHTENING PRESSURE GRADIENT DEVELOPING FROM THE
CAROLINAS INTO THE MID-ATLANTIC STATES. SIGNIFICANT ADVECTION OF
WARMER AIR FROM THE SOUTHWEST WILL OCCUR TONIGHT WITH TEMPERATURES
AS CLOSE AS 1000-1500 FT TO THE GROUND ACTUALLY INCREASING AS THE
NIGHT WEARS ON. THE STRONGEST THERMAL ADVECTION WILL OCCUR AROUND
THE 800 MB LEVEL (ABOUT 7000 FT AGL) WHERE 24-HOUR TEMPERATURE
CHANGES OF +13C/23F WILL OCCUR THROUGH DAYBREAK WEDNESDAY. 1000-500
MB THICKNESSES RISE ABOUT 90 METERS OVERNIGHT AS WELL.

CLEAR NIGHTS WITH STRONG THERMAL ADVECTION ARE OFTEN SOME OF THE
MOST DIFFICULT TO FORECAST JUST INLAND FROM THE BEACHES WHERE A
SHALLOW RADIATIONAL INVERSION MAY ONLY INTERMITTENTLY DEVELOP...OR
NOT DEVELOP AT ALL!  GIVEN THE ONSHORE WIND DIRECTION FROM MYRTLE
BEACH UP THROUGH OAK ISLAND AND BALD HEAD ISLAND I HAVE RAISED
FORECAST LOWS SEVERAL DEGREES FOR THE BEACHES AND BARRIER ISLANDS
HERE ANTICIPATING INCREASING WINDS WILL PREVENT A RADIATIONAL
INVERSION TONIGHT. FARTHER INLAND GOOD RADIATIONAL COOLING EARLY
WILL ALLOW TEMPERATURES TO PLUMMET INTO THE 51-55 RANGE...BUT I
ANTICIPATE A NEARLY FLAT-LINE TEMPERATURE CURVE AFTER MIDNIGHT AS
INCREASING WINDS AT THE TOP OF THE BOUNDARY LAYER (1000 FT WIND
SPEEDS INCREASING TO 25 KNOTS) ADD TURBULENCE WITHIN THE NOCTURNAL
RADIATION INVERSION.

SKIES SHOULD REMAIN GENERALLY CLEAR OVERNIGHT WITH THE BEST SHOT OF
CLOUDS EARLY THIS EVENING ACROSS THE BURGAW-WILMINGTON AREA AS SOME
ALTOCU SHOOT ACROSS IN A NORTHWEST FLOW ALOFT.
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&&

.SHORT TERM /6 AM THIS MORNING THROUGH THURSDAY NIGHT/...
AS OF 3 PM TUESDAY...SUMMERTIME HEAT IS UPON US! A SHORTWAVE RIDGE
WILL BUILD ACROSS THE SOUTHEAST STATES THIS PERIOD. THE RIDGE WILL
BE MOST PRONOUNCED WED...THEN GET KNOCKED DOWN SLIGHTLY ON THU AS A
SHORTWAVE TROUGH MOVES ACROSS THE AREA. ALTHOUGH THE COLUMN DOES
MOISTEN ABOVE 10 KFT LATE THU AND THU NIGHT...IT REMAINS TOO DRY
WITHIN 10 KFT OF THE GROUND TO SUPPORT PRECIPITATION. THUS...WILL
NOT INCLUDE POPS FOR MEASURABLE PRECIPITATION AT THIS TIME. WILL
HOWEVER...INCLUDE MORE CLOUDS THU AND THU NIGHT...GENERALLY OF THE
MID AND HIGH VARIETY.

RISING HEIGHTS AND AN INCREASINGLY GUSTY SW WIND WILL DRIVE TEMPS
WELL ABOVE NORMAL. MOST LOCATIONS ON WED WILL REACH THE MID AND
UPPER 80S. VERY NEAR THE COAST...A PINNED SEABREEZE WILL SUPPRESS
HIGHS TO THE UPPER 70S AND LOWER 80S...COOLEST ACROSS COASTAL
BRUNSWICK AND SOUTHERN NEW HANOVER COUNTIES. TEMPS ON THU WILL BE
SIMILAR...BUT A MORE WESTERLY WIND REGIME SHOULD ALLOW FOR HIGHER
TEMPS AT THE BEACHES. LIKEWISE...LOWS WILL BE ABOVE NORMAL THROUGH
THE PERIOD...LOWER TO MID 60S.

&&

.LONG TERM /FRIDAY THROUGH TUESDAY/...
AS OF 3 PM TUESDAY...SUMMER-LIKE PATTERN CONTINUES THROUGH THE
EXTENDED AS BERMUDA- TYPE HIGH PRESSURE ANCHORS OFFSHORE WHILE
ZONAL 5H FLOW GRADUALLY BECOMES MORE AMPLIFIED INTO EARLY NEXT
WEEK. THIS CREATES FAIRLY TYPICAL SUMMERTIME SENSIBLE
WEATHER...WITH TEMPS RISING WELL INTO THE 80S AWAY FROM THE COAST
AND SCATTERED AFTN CONVECTION. WITH WARM/MOIST ADVECTION
CONTINUING EACH DAY...PWATS RISE FROM AROUND 1.2 INCHES
FRIDAY...TO 1.6 INCHES TUESDAY. WHILE EACH DAY WILL SUPPORT A
CHANCE FOR AFTN CONVECTION...SUN-TUE WILL HAVE SLIGHTLY BETTER
CHANCES THANKS TO THE INCREASED MOISTURE. CONVECTION IS POSSIBLE
ALONG THE TYPICAL SUMMERTIME BOUNDARIES...SEA BREEZE FRONT AND
PIEDMONT TROUGH. WHILE A BACK DOOR COLD FRONT WILL APPROACH FROM
THE NORTH FRIDAY...ATTM DO NOT EXPECT IT TO REACH THE LOCAL CWA AS
IT GETS HUNG UP JUST NORTH OF THE AREA THANKS TO LITTLE UPPER
SUPPORT AND RESISTANCE FROM LOW-LEVEL SW FLOW.

GFS SHOWS A STRONG VORT MAX DIVING SE INTO A RIDGE WEAKNESS AND
SPAWNING CYCLOGENESIS OFF THE MID-ATLANTIC COAST WHICH DRIVES A COLD
FRONT INTO THIS AREA MON/TUE. THIS IS CURRENTLY THE OUTLIER AND THUS
A CMC/ECMWF SOLUTION IS PREFERRED FOR EARLY WEEK WITH CONTINUED
WARMTH AND DIURNAL CONVECTIVE CHANCES.

TEMPS THROUGH THE PERIOD WILL BE AROUND TO SLIGHTLY ABOVE
CLIMO...LOW TO MID 80S FOR HIGHS...AND LOW TO MID 60S FOR LOWS.

&&

.AVIATION /06Z WEDNESDAY THROUGH SUNDAY/...
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AS OF 06Z...EXPECT VFR CONDITIONS AT ALL TERMS THROUGH THE VALID TAF
PERIOD. SOUTHWEST WINDS WILL REMAIN 5-10 KTS THROUGH 12Z WITH
20-30 KT WINDS JUST OFF THE SFC...AROUND 1-2KFT AGL. HAVE ADDED
LOW-LEVEL WIND SHEAR FOR KLBT/KFLO BEGINNING AT 06Z WHERE
FORECAST SOUNDINGS INDICATE THE LOW-LEVEL WINDS WILL BE STRONGEST.
SFC WINDS WILL PICK UP AFTER 12Z AS THE PRESSURE GRADIENT TIGHTENS
ACROSS THE CAROLINAS. SOUTHWEST WINDS 10-20 KTS AND GUSTS AROUND
25 TO 30 KTS LIKELY WILL PERSIST THROUGH THE DAY. THE GUSTS WILL
BEGIN SUBSIDING AFTER 00Z THURSDAY...BUT SOUTHWEST WINDS WILL
REMAIN 8-12 KTS THROUGH THE EVENING HOURS.

EXTENDED OUTLOOK...VFR LIKELY THROUGH FRIDAY. SLIGHT CHANCE OF
SHOWERS/TSTMS SATURDAY AND SUNDAY.
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&&

.MARINE...
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NEAR TERM /THROUGH TONIGHT/...
AS OF 1:30 AM WEDNESDAY...NO CHANGES TO THE FORECAST WITH THE
LATEST UPDATE. PREVIOUS DISCUSSION FOLLOWS:

SEAS ARE BEGINNING TO INCREASE SLIGHTLY... AVERAGING 2.5 TO 3 FEET
AT DATA BUOYS CLUSTERED NEAR CAPE FEAR. WINDS HAVE INCREASED AS
WELL TO 12-15 KNOTS. MODELS SHOW THERE SHOULD BE ONLY A SLIGHT
ADDITIONAL INCREASE IN WINDS OR WAVES OVERNIGHT...WITH THE BULK OF
THE DETERIORATING MARINE CONDITIONS DEVELOPING DURING THE DAY
WEDNESDAY AS WINDS PUSH ABOVE 20 KNOTS AT TIMES. ASIDE FROM THESE
MINOR UPWARD ADJUSTMENTS THE FORECAST REMAINS UNCHANGED THIS
EVENING.

SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/...
AS OF 3 PM TUESDAY...THE PRESSURE GRADIENT IS EXPECTED TO TIGHTEN
BETWEEN A DEVELOPING TROUGH TO OUR W AND AN AREA OF HIGH PRESSURE
SUPPRESSED TO OUR S AND SE. SW WINDS ARE EXPECTED TO INCREASE WED
AFTERNOON AND WILL HOIST A SMALL CRAFT ADVISORY FOR WED AFTERNOON
AND WED NIGHT. SEAS WILL BUILD AS A RESULT OF THESE INCREASING
WINDS...UP TO 4 TO 7 FT...HIGHEST ACROSS THE OFFSHORE WATERS. THE
GRADIENT LOOKS A LITTLE SLACKER ON THU...BUT IT IS POSSIBLE THAT
MARGINAL SMALL CRAFT ADVISORY CONDITIONS COULD LINGER INTO THU FOR
PORTIONS OF THE AREA. HOWEVER...WINDS AND SEAS ARE EXPECTED TO PEAK
WED AFTERNOON AND NIGHT AND THEN SHOW A DIMINISHING TREND FOR THE
REMAINDER OF THE PERIOD.

LONG TERM /FRIDAY THROUGH SUNDAY/...
AS OF 3 PM TUESDAY...BERMUDA-TYPE HIGH PRESSURE WILL REMAIN IN
CONTROL THROUGH THE EXTENDED CREATING GENERALLY LIGHT TO MODERATE
SW WINDS ACROSS THE WATERS. SPEEDS OF 10-15 KTS WILL BE COMMON
EACH DAY...WITH ONLY MINOR DIURNAL FLUCTUATIONS. A WEAK SE SWELL
WILL BE PRESENT WITHIN THE SPECTRUM EACH DAY...BUT WITH SUCH LOW
AMPLITUDE WILL CONTRIBUTE LITTLE TO THE SIGNIFICANT WAVE
AMPLITUDE. THUS...WAVE HEIGHTS OF 2-4 FT WILL BE PRESENT THROUGH
THE PERIOD WITH A 4-5 SEC SW WIND CHOP THE PRIMARY WAVE GROUP.
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&&

.ILM WATCHES/WARNINGS/ADVISORIES...
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SC...NONE.
NC...NONE.
MARINE...SMALL CRAFT ADVISORY FROM NOON TODAY TO 6 AM EDT THURSDAY FOR
     AMZ250-252-254-256.
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&&

$$

NEAR TERM...REK/RGZ
SHORT TERM...RJD
LONG TERM...JDW
AVIATION...BJR
MARINE...REK/RJD/JDW/RGZ