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-- Discussion containing changed information from previous version are highlighted. --
000
FXUS62 KILM 181016
AFDILM

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE WILMINGTON NC
616 AM EDT SAT MAY 18 2013

.SYNOPSIS...
HIGH PRESSURE ANCHORED OFFSHORE WILL CONTINUE TO BRING WARM
TEMPERATURES INTO EARLY NEXT WEEK. WEAK LOW PRESSURE ALOFT WILL
BRING INCREASING CHANCES FOR AFTERNOON AND EVENING THUNDERSTORMS
THIS WEEKEND AND EARLY NEXT WEEK. DRIER WEATHER WITH CONTINUED
WARM TEMPERATURES IS EXPECTED FOR THE MIDDLE AND LATTER PORTIONS
OF NEXT WEEK.

&&

.NEAR TERM /THROUGH TONIGHT/...
-- Changed Discussion --
AS OF 6:30 AM SATURDAY...NO CHANGES TO THE FORECAST WITH THE
LATEST UPDATE. PREVIOUS DISCUSSION FOLLOWS:

WARM SOUTHERLY FLOW WILL CONTINUE THROUGH THE PERIOD AS A COLD
FRONT REMAINS STALLED TO THE NORTH. FLOW AT PRESENT IS ACTUALLY
MAINLY FROM THE SW...BUT A SLIGHT RE- ORIENTATION OF THE WESTERN
ATLANTIC HIGH WILL BRING A MORE SOUTHERLY COMPONENT TO SURFACE
WINDS BY AFTERNOON. THIS WILL GIVE AN EXTRA KICK INLAND TO THE SEA
BREEZE CIRCULATION THAT WILL START DEVELOPING LATER THIS MORNING.
AS FLOW WILL BE MORE SOUTHERLY AND THUS BRINGING WITH IT A GREATER
MARINE INFLUENCE EXPECT TEMPERATURES WILL NOT BE AS HIGH AS
RECENTLY. INCREASING CLOUD COVER WILL ALSO HELP KEEP A LID ON
TEMPERATURES. HOWEVER...READINGS WILL STILL COME IN A BIT ABOVE
AVERAGE. GUIDANCE IN EXCELLENT AGREEMENT WITH HIGHS IN THE MID 80S
MOST LOCATIONS...AND AROUND 80 AT THE BEACHES.

CHANCES FOR PRECIPITATION WILL GRADUALLY RAMP UP THROUGH THE
PERIOD...ALTHOUGH ODDS WILL REMAIN MODEST IN AN ABSOLUTE SENSE. BEST
CHANCES FOR CONVECTION WILL BE WELL INLAND...ESPECIALLY OVERNIGHT AS
A BROAD UPPER LEVEL WEAKNESS ADVANCES UPON THE AREA. MOST
PLACES...ESPECIALLY TOWARDS THE COAST...WILL BE IN THE SLIGHT CHANCE
CATEGORY.

OVERNIGHT LOWS WILL REMAIN ABOVE AVERAGE...IN THE MID 60S...AS
SOUTHERLY FLOW AND EXTENSIVE CLOUD COVER CONTINUES.
-- End Changed Discussion --

&&

.SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/...
AS OF 300 AM SATURDAY...SLOWLY WEAKENING SHORTWAVE TROUGH WILL DRIFT
OVERHEAD DURING THE SHORT TERM...COMBINING WITH RICH THETA-E AIR ON
RETURN FLOW TO CREATE SCATTERED-TO-WIDESPREAD CONVECTION EACH AFTN.
BERMUDA HIGH PRESSURE ANCHORED OFFSHORE WILL CONTINUALLY PUMP
WARM/MOIST AIR INTO THE REGION WITH PWATS RISING TO 1.6-1.8 INCHES.
THIS IS A PATTERN WHICH TYPICALLY SUPPORTS SCATTERED AFTN
CONVECTION. IN THIS CASE HOWEVER...THANKS TO THE PRESENCE OF THE 5H
SHORTWAVE ENHANCING LIFT AND PROMOTING STEEPER LAPSE RATES DUE TO A
COOL POOL ALOFT...EXPECT CONVECTION TO BE MORE WIDESPREAD THAN IS
USUAL FOR THIS SETUP. WITH TEMPS RISING INTO THE LOW/MID 80S EACH
AFTN...MLCAPE WILL RISE WELL ABOVE 1000 J/KG...FUELING CONVECTION
ALONG THE SEA BREEZE FRONT AND PIEDMONT TROUGH. SREF PROBS FOR 0.01"
RISE TO 100% (TYPICALLY A SIGNAL THAT QPF IS LIKELY) BOTH SUN AND
MON ACROSS THE WESTERN HALF OF THE CWA. WILL BUMP POP TO LIKELY FOR
THIS AREA BOTH AFTNS. WHILE SEVERE CONVECTION SEEMS UNLIKELY WITH
STORM ORGANIZATION LIMITED...BRIEFLY TORRENTIAL RAIN WILL OCCUR
WITHIN TSTMS DUE TO THE SATURATED COLUMN.

EVEN THOUGH CONVECTION WILL BE DIURNALLY FORCED...RESIDUAL ELEVATED
INSTABILITY NOTED IN FORECAST SOUNDINGS SUGGESTS THAT OUTFLOW
BOUNDARIES WILL ALLOW TSTMS TO LIVE ON SEVERAL HOURS BEYOND
NOCTURNAL COOLING...AND HAVE CONTINUED AT LEAST SCHC EACH NIGHT
DURING THE SHORT TERM. MINS EACH NIGHT WILL BE WELL ABOVE CLIMO FOR
MID-MAY...FALLING INTO THE MID 60S...UPR 60S AT THE COAST.

&&

.LONG TERM /TUESDAY THROUGH FRIDAY/...
AS OF 300 AM SATURDAY...WARM AND SUMMER-LIKE CONDITIONS PERSIST
DURING THE EXTENDED AS BERMUDA HIGH SITS OFFSHORE AND MID-LEVEL
RIDGING BULGES FROM THE GULF COAST. WHILE DIURNAL CONVECTION WILL BE
POSSIBLE EACH AFTN...COMBINATION OF SOME SUBSIDENCE BEHIND A
DEPARTING SHORTWAVE AND BUILDING HEIGHTS ALOFT SHOULD LIMIT OVERALL
TSTM POTENTIAL...ESPECIALLY WED/THU. BY LATE IN THE WEEK...UPPER
TROUGH BEGINS TO DISPLACE THE RIDGE...AND A COLD FRONT APPROACHES
FROM THE NW. DO NOT EXPECT ANY SIGNIFICANT AIRMASS CHANGES OR COLD
FRONT IMPACTS BEFORE NEXT WEEKEND...BUT TSTM POTENTIAL WILL AGAIN
INCREASE LATE IN THE PERIOD. WARMEST DAYS WILL BE WED/THU...BUT ALL
DAYS WILL BE CLIMO...TO SLIGHTLY ABOVE...FOR BOTH HIGHS AND LOWS.

&&

.AVIATION /10Z SATURDAY THROUGH WEDNESDAY/...
AS OF 06Z...MID-LEVEL CLOUDS CONTINUE STREAMING OVER OUR CWA TONIGHT
AHEAD OF AN ADVANCING UPPER DISTURBANCE. IT LOOKS LIKE THE WINDS AND
CLOUD COVER WILL SUPPRESS MOST FOG DEVELOPMENT OVERNIGHT...BUT TEMPO
MVFR VSBYS ARE STILL POSSIBLE AT KLBT/KFLO. ON SATURDAY...EXPECT
INCREASING LOW/MID-LEVEL CLOUDS WITH S-SW WINDS 8-12 KTS. ISOLATED
AFTN SHOWERS/TSTMS ARE POSSIBLE...BUT HAVE NOT MENTIONED ANY PCPN IN
THE TAFS ATTM AS COVERAGE WILL BE LIMITED IF ANY SHOWERS DEVELOP.
CIGS WILL LOWER AFTER 00Z...BUT IT APPEARS THAT VFR SHOULD PREVAIL
THROUGH THE END OF THE PERIOD.

EXTENDED OUTLOOK...AFTN SHOWERS/TSTMS POSSIBLE THROUGH MONDAY.
OTHERWISE VFR.

&&

.MARINE...
-- Changed Discussion --
NEAR TERM /THROUGH TONIGHT/...
AS OF 6:30 AM SATURDAY...NO CHANGES TO THE FORECAST WITH THE
LATEST UPDATE. PREVIOUS DISCUSSION FOLLOWS:

LIGHT SOUTH TO SW WINDS OF AROUND 10 KTS WILL CONTINUE THROUGH
THE PERIOD FOR MUCH OF THE WATERS AS A FRONT REMAINS STALLED WELL
TO THE NORTH AND HIGH PRESSURE EXTENDS OVER THE WESTERN ATLANTIC.
THE EXCEPTION WILL BE NEAR-SHORE THIS AFTERNOON AS A SEA BREEZE
CIRCULATION BRINGS NEAR-SHORE WINDS UP TO AROUND 15 KTS. SEAS WILL
NOT STRAY FAR FROM PRESENT 2 FT RANGE...ALTHOUGH THEY COULD GET
CHOPPY THIS AFTERNOON NEAR SHORE DUE TO THE SEA BREEZE.

SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/...
AS OF 300 AM SATURDAY...FAIRLY STAGNANT PATTERN FOR THE SHORT TERM
AS BERMUDA HIGH PRESSURE SITS OFFSHORE. WHILE OVERALL GRADIENT WILL
NOT BE VERY STRONG...S/SW WINDS AROUND THIS HIGH PRESSURE WILL BE
10-15 KTS THROUGH THE PERIOD WITH LITTLE DIURNAL OR DIRECTIONAL
FLUCTUATION. WITH BERMUDA HIGH SITTING OFFSHORE...PERSISTENT EAST
AND SOUTH WINDS AROUND IT WILL PROMOTE AN INCREASINGLY LONG-PERIOD
SWELL...BECOMING 2-3 FT AT 10 SEC ON MONDAY. THIS COMBINED WITH THE
S/SW WINDS WILL DRIVE SEAS UP TO 3-5 FT EACH DAY DURING THE PERIOD.

LONG TERM /TUESDAY THROUGH WEDNESDAY/...
AS OF 300 AM SATURDAY...CONTINUED BERMUDA RIDGE SITTING OFFSHORE
WILL KEEP PERSISTENT 10-15 KTS OF S/SW WINDS OVER THE WATERS. THE
LONG TEMPORAL DURATION OF THIS FETCH AROUND THE OFFSHORE HIGH WILL
KEEP A 2FT/10 SEC SE SWELL IN THE WAVE SPECTRUM...WHICH WILL COMBINE
WITH 3-4 FT SOUTHERLY WIND CHOP. THESE TWO WILL DRIVE SEAS TO 3-4 FT
THROUGH THE PERIOD WITH LITTLE VARIABILITY.
-- End Changed Discussion --

&&

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

&&

$$

SYNOPSIS...JDW
NEAR TERM...REK
SHORT TERM...JDW
LONG TERM...JDW
AVIATION...REK/BJR
MARINE...REK/JDW