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-- Discussion containing changed information from previous version are highlighted. --
000
FXUS62 KILM 181452
AFDILM

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE WILMINGTON NC
1052 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 10:30 AM SATURDAY...THE LATEST HIGH RESOLUTION GUIDANCE
CONTINUES TO KEEP THE WESTERN ZONES THE FAVORED AREAS FOR CONVECTION
THIS AFTERNOON AND EVENING. AN OUTFLOW BOUNDARY AS WELL AS BROAD
HEIGHT FALLS SHOULD SHOULD PROVIDE THE CATALYST. NO CHANGES TO
POPS...WHICH REPRESENT THE CURRENT TRENDS WELL OR EXPECTED MAX
TEMPERATURES.
-- 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 /15Z SATURDAY THROUGH WEDNESDAY/...
AS OF 12Z...AFTER ANY RESIDUAL MORNING FOG BURNS OFF THIS
AM...EXPECT VFR CONDITIONS THROUGH THE MOST OF THE PERIOD.  THERE IS
A SMALL CHANCE OF THUNDERSTORMS THIS AFTERNOON AND EVENING...MAINLY
AT LBT/FLO.  AT THIS TIME...THE CHANCE AT INDIVIDUAL TAF SITES
REMAINS LOW ENOUGH THE EXCLUDE FROM THE TAFS.  WINDS SHOULD BE S TO
SW 5 TO 10 KT DURING DAYLIGHT HOURS.

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

&&

.MARINE...
-- Changed Discussion --
NEAR TERM /THROUGH TONIGHT/...
AS OF 10:30 AM SATURDAY...WINDS AND SEAS REMAIN LIGHT ACROSS THE
COASTAL WATERS THIS MORNING WITH SIX KNOTS AND JUST OVER TWO FEET
AT 41013. NO CHANGES EXPECTED THROUGH THE PERIOD WITH A SOUTHERLY
FLOW AROUND TEN KNOTS WITH SEAS TWO FEET OR SO. ANY CONVECTION
THAT MAY DISTORT WINDS TEMPORARILY IS EXPECTED TO REMAIN INLAND.

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...SHK
SHORT TERM...JDW
LONG TERM...JDW
AVIATION...RAN