-- Discussion containing changed information from previous version are highlighted. --
000
FXUS62 KILM 152321
AFDILM

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE WILMINGTON NC
721 PM EDT WED MAY 15 2013

.SYNOPSIS...
WARM TEMPERATURES WILL CONTINUE THROUGH EARLY NEXT WEEK AS HIGH
PRESSURE PUSHES OFFSHORE. THERE IS A SMALL RISK FOR MAINLY
AFTERNOON AND EVENING SHOWERS AND THUNDERSTORMS BEGINNING FRIDAY.

&&

.NEAR TERM /UNTIL 6 AM THURSDAY MORNING/...
-- Changed Discussion --
AS OF 730 PM WEDNESDAY...MY LARGEST CHANGE TO THE FORECAST WAS TO
RAISE WIND SPEEDS NEAR THE COAST THROUGH THE EVENING HOURS BY 5 MPH
OR SO. IT WILL TAKE AWHILE FOR THE SEABREEZE TO "WIND DOWN" GIVEN
VERY LARGE TEMPERATURE CONTRASTS THAT FUELED IT THIS AFTERNOON. ALSO
I HAVE RAISED LOWS BY A DEGREE OR TWO...ESPECIALLY ALONG THE COAST
WHERE IT APPEARS A SOUTHWESTERLY LOW LEVEL JET WILL HELP KEEP THE
BOUNDARY LAYER RATHER WELL STIRRED FOR MOST OF THE NIGHT. ANY OTHER
CHANGES ARE VERY MINOR. PREVIOUS DISCUSSION FROM 300 PM FOLLOWS...

BREEZY AND WARM CONDITIONS WILL CONTINUE THROUGH THIS AFTERNOON AS
TEMPS IN THE 80S ACROSS MUCH OF THE AREA EXCEPT ALONG THE COAST.
GUSTY SOUTHWEST WINDS WILL CONTINUE THROUGH THIS EVENING AS HIGH
PRESSURE REMAINS ANCHORED TO THE EAST AND LOW PRESSURE SYSTEM PASSES
TO THE NORTH. THE TIGHTENED GRADIENT WILL PRODUCE SW WINDS GUSTING
OVER 20 MPH THROUGH THIS AFTERNOON. 850 TEMPS WILL RISE UP TO 18C AS
MID TO UPPER RIDGE BUILDS OVERHEAD.  PCP WATER VALUES AROUND .75
INCHES DO INCREASE ABOVE AN INCH THROUGH TONIGHT AS SOME OF THE
MOISTURE ASSOCIATED WITH SYSTEM TO THE NORTH REACHES DOWN OVER THE
RIDGE INTO NORTH CAROLINA. THIS MAY PRODUCE A FEW MID TO HIGH CLOUDS
OVER THE AREA...BUT OVERALL EXPECT CLEAR SKIES THROUGH TONIGHT. SEA
BREEZE WILL COME AGAINST STRONG SOUTHWEST WIND BUT WILL MAKE ITS WAY
IN FROM THE BEACHES LATER THIS AFTERNOON BRINGING LATE AFTERNOON
TEMPS DOWN SEVERAL DEGREES CLOSE TO THE COAST.

MID TO UPPER RIDGE HOLDS OVER THE SOUTHEAST THROUGH TONIGHT
MAINTAINING DRY CONDITIONS WITH PLENTY OF SUBSIDENCE. SOUTHWEST
FLOW WILL CONTINUE AS LOW PRESSURE SYSTEM PASSES ACROSS THE
NORTHEAST WITH TROUGH RUNNING DOWN THROUGH INLAND CAROLINAS AND
HIGH PRESSURE HOLDING OFF SHORE. EXPECT WINDS TO DIMINISH THROUGH
THIS EVENING BUT REMAIN UP TO 5 TO 10 MPH THROUGH THE NIGHT IN
THIS TIGHTENED GRADIENT FLOW. THESE WINDS WILL HELP KEEP A FLOW OF
WARM AND MOIST AIR INTO THE AREA WITH DEWPOINT TEMPS RISING UP
CLOSE TO 60 F BY MORNING WITH OVERNIGHT LOWS HOLDING ABOVE 60
DEGREES.
-- End Changed Discussion --

&&

.SHORT TERM /6 AM THURSDAY MORNING THROUGH FRIDAY NIGHT/...
AS OF 3 PM WEDNESDAY...WARM ATLANTIC RIDGING WILL DOMINATE THE
PERIOD. A PIEDMONT TROUGH WILL REMAIN IN PLACE. A BACKDOOR COLD
FRONT WILL STRUGGLE TO MAKE SOUTHWARD PROGRESS AS IT DRIFTS ACROSS
VIRGINIA THU AND THU NIGHT AND THEN INTO NORTH CAROLINA FRI AND FRI
NIGHT. AT THIS TIME THE FRONT SHOULD GET HUNG UP N OF OUR FORECAST
AREA...PERHAPS GETTING CLOSE TO THE ONSLOW-PENDER COUNTY LINE BY SAT
MORNING AS IT BECOMES INCREASINGLY ILL-DEFINED.

IN TERMS OF HOW THIS WILL IMPACT OUR SENSIBLE WEATHER...IT WILL
REMAIN WARM THROUGH THE PERIOD. HIGH TEMPS ARE EXPECTED TO BE
SIMILAR TO THIS AFTERNOON...REACHING WELL UP INTO THE 80S BOTH DAYS.
A FEW SPOTS WILL LIKELY AGAIN TOUCH 90 DEGREES...ESPECIALLY ACROSS
PORTIONS OF THE PEE DEE ON THU. THE SEABREEZE WILL BE PINNED
RELATIVELY CLOSE TO THE COAST GIVEN THE DEEP WESTERLY FLOW. THUS...
EVEN THE BEACHES WILL REACH THE LOWER TO PERHAPS MID 80S WITH THE
EXCEPTION OF LOCATIONS ACROSS SOUTHERN NEW HANOVER AND COASTAL
BRUNSWICK COUNTIES WHERE MARINE INFLUENCES WILL LIKELY KEEP HIGHS
CLOSER TO 80 DEGREES. NIGHTTIME TEMPS WILL ALSO BE ABOVE NORMAL...
MID AND UPPER 60S ARE EXPECTED TO BE COMMON.

THIS SUMMERTIME PATTERN WILL NOT BE ESPECIALLY CONDUCIVE FOR SHOWERS
AND THUNDERSTORMS GIVEN THE DRY AIR BELOW 15 KFT AND THE LACK OF
SIGNIFICANT TRIGGERS ALOFT. THE DEEP AND SUBSIDENT WESTERLY FLOW
WILL ALSO BE A LIMITING FACTOR. CONFIDENT THAT DRY WEATHER WILL
PERSIST THROUGH THU NIGHT. ON FRI...THE DRY AIR SHRINKS...CONFINED
TO THE LOWEST 5-6 KFT OF THE COLUMN. THUS...GIVEN THE AFOREMENTIONED
SURFACE FEATURES...CAN NOT RULE OUT THE DEVELOPMENT OF ISOLATED TO
PERHAPS SCATTERED SHOWERS AND THUNDERSTORMS. THE COVERAGE MAY BE
GREATEST ALONG THE SEABREEZE AND THE PIEDMONT TROUGH WHERE THERE
WILL BE SOME WEAK CONVERGENCE. WANING CONVECTION TO OUR N...
ASSOCIATED WITH THE BACKDOOR COLD FRONT...MAY APPROACH THE AREA
FRI NIGHT.

&&

.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
AS OF 3 PM WEDNESDAY...PERSISTENT SUMMER-LIKE PATTERN EXPECTED
THROUGH THE LONG TERM AS BERMUDA HIGH PRESSURE SITS ANCHORED
OFFSHORE. WHILE THIS LEAVES WARM S/SW RETURN FLOW ACROSS THE
CAROLINAS...WITH TEMPS RISING TO NEAR/ABOVE NORMAL EACH
DAY...THERE IS A POTENTIAL FLY-IN-THE-OINTMENT WITH A BACK DOOR
COLD FRONT STALLING VERY NEAR THE CWA. AT THIS TIME...BELIEVE THE
FRONT WILL REMAIN JUST TO THE NORTH OF THE LOCAL AREA THANKS TO
RETURN FLOW IMPEDING ITS SOUTHERN MOTION...AND THE FACT THAT WE
ARE MOVING BEYOND THE CLIMATOLOGICALLY FAVORED PERIOD FOR BACK
DOOR COLD FRONTS TO SINK THIS FAR SOUTH. HOWEVER...A SLOW MOVING
VORT EMBEDDED WITHIN THE AMPLIFYING MID-LEVEL FLOW WILL MOVE OVER-
TOP THE STALLED BOUNDARY...INCREASING RAIN/CONVECTION CHANCES
ALONG THE FRONT. FOR THIS REASON THERE IS SOME UNCERTAINTY IN POP
AND TEMPS...SINCE IF THE FRONT SAGS INTO THE CWA MAX TEMPS WILL
LOWER...AND POP WILL INCREASE. WITH BEST SUPPORT FOR FRONT
REMAINING NORTH...WILL KEEP INHERITED LOW-CHC POP FOR DIURNAL
CONVECTION WITH TEMPS IN THE LOW/MID 80S. LATE IN THE PERIOD...5H
HEIGHTS REBUILD ACROSS THE SOUTHEAST...BRINGING A SLIGHT WARMING
TREND AND DECREASING CHANCES FOR CONVECTION.

&&

.AVIATION /00Z THURSDAY THROUGH MONDAY/...
-- Changed Discussion --
AS OF 00Z...VFR CONDITIONS ARE EXPECTED THROUGH THIS TAF PERIOD.
SOUTHWEST WINDS WILL REMAIN 5-10 KTS OVERNIGHT WITH THE ENHANCED
PRESSURE GRADIENT OVER THE CAROLINAS. DESPITE CLEAR SKIES AND SFC
DEWPOINTS NEAR 60 DEGREES ACROSS THE AREA...THE WINDS SHOULD INHIBIT
ANY OVERNIGHT FOG FORMATION. EXPECT SOUTHWEST WINDS 10-15 KTS ON
THURSDAY ALONG WITH SOME SCT CIRRUS IN THE AFTN HOURS. WIND GUSTS UP
TO 20 KTS ARE POSSIBLE...MOST LIKELY ALONG THE COAST.

EXTENDED OUTLOOK...CHANCE OF AFTN SHOWERS/TSTMS FRIDAY THROUGH
MONDAY...OTHERWISE VFR.
-- End Changed Discussion --

&&

.MARINE...
-- Changed Discussion --
NEAR TERM /THROUGH TONIGHT/...
AS OF 730 PM WEDNESDAY...ON THIS EARLY EVENING UPDATE I HAVE RAISED
WIND SPEEDS BY UP TO 5 KNOTS FOR THE NEARSHORE WATERS WHERE A STRONG
SEABREEZE CIRCULATION WILL TAKE SEVERAL MORE HOURS TO WIND DOWN
GIVEN THE IMPRESSIVE TEMPERATURE GRADIENTS OBSERVED THIS AFTERNOON.
WIND SPEEDS ARE GUSTING OVER 20 KNOTS AT VIRTUALLY EVERY BEACH
REPORTING STATION FROM MYRTLE BEACH THROUGH BALD HEAD ISLAND TO
WRIGHTSVILLE BEACH AND TOPSAIL ISLAND. CURRENT SEAS MATCHED LATEST
FORECASTS CLOSELY AND NO CHANGES WERE NECESSARY THERE. PREVIOUS
DISCUSSION FROM 300 PM FOLLOWS...

SOUTHWEST WINDS GUSTING UP TO 25 TO 30 KTS THIS AFTERNOON IN
TIGHTENED GRADIENT FLOW BETWEEN HIGH PRESSURE OFF SHORE AND LOW
PRESSURE SYSTEM PASSING BY TO THE NORTH. WINDS WILL CONTINUE TO
REMAIN STRONG AND GUSTY THROUGH THIS AFTERNOON PUSHING WINDS AND
SEAS INTO SMALL CRAFT ADVISORY THRESHOLDS.

SMALL CRAFT ADVISORY REMAINS IN EFFECT FROM NOON THROUGH 6AM THURS
MORNING. WINDS WILL INCREASE TO 20 TO 25 KTS THIS AFTERNOON...WITH
SEAS BUILDING TO 4 TO 6 FT. WNA SHOWS PEAK IN SEAS AROUND MIDNIGHT
TONIGHT WITH A STEADY DECREASE THEREAFTER AS GRADIENT RELAXES A
BIT WITH CONTINUED SW TO W FLOW 15 TO 20 KTS THROUGH EARLY
THURSDAY.

SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
AS OF 3 PM WEDNESDAY...BERMUDA HIGH PRESSURE WILL DOMINATE THROUGH
THE PERIOD. THE PIEDMONT TROUGH IN CONJUNCTION WITH THIS RIDGE WILL
HELP KEEP SOME GRADIENT ACROSS THE WATERS. A WEAKENING BACKDOOR COLD
FRONT WILL DRIFT SOUTHWARD FRI AND FRI NIGHT...BUT THE FRONT IS
EXPECTED TO REMAIN TO OUR N THROUGH SAT MORNING. SW WINDS WILL
CONTINUE THROUGH THE PERIOD. WINDS SHOULD BE A LITTLE HIGHER ON THU
GIVEN THE SLIGHTLY TIGHTER PRESSURE GRADIENT AS COMPARED TO FRI.
WILL FORECAST 15 TO 20 KT THU AND 10 TO 15 KT ON FRI. EXPECT 3 TO 4
FT SEAS ON THU TO SUBSIDE ABOUT A FOOT FOR FRI.

LONG TERM /SATURDAY THROUGH MONDAY/...
AS OF 3 PM WEDNESDAY...SUMMERTIME PATTERN DURING THE EXTENDED
WITH HIGH PRESSURE ANCHORED OFFSHORE PUMPING S/SW RETURN FLOW
ACROSS THE WATERS. WHILE A BACK DOOR COLD FRONT WILL BE TRYING TO
SAG SOUTH INTO THE NORTHERN WATERS AT THE START OF THE
PERIOD...ATTM DO NOT EXPECT ANY VEERING OF WINDS EVEN ACROSS THE
NORTHERN EDGE OF AMZ250...BUT WILL HAVE TO MONITOR THIS AS THE
WEEKEND APPROACHES. WHILE THE FRONT STAYS NORTH...S/SW WINDS WILL
PERSIST THROUGH THE PERIOD...AT SPEEDS OF AROUND 10
KTS...INCREASING TO 10-15 KTS ON MONDAY. SEAS OF 2-3 FT WILL BE
COMMON DURING THE WKND...GROWING TO 2-4 FT MONDAY THANKS TO THE
SLIGHTLY INCREASED WIND SPEEDS.
-- End Changed Discussion --

&&

.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 6 AM EDT THURSDAY FOR AMZ250-252-
     254-256.

&&

$$
NEAR TERM...RGZ/TRA
SHORT TERM...RJD
LONG TERM...JDW
AVIATION...BJR