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-- Discussion containing changed information from previous version are highlighted. --
000
FXUS62 KILM 250534 CCA
AFDILM

AREA FORECAST DISCUSSION...COR
NATIONAL WEATHER SERVICE WILMINGTON NC
132 AM EDT SAT MAY 25 2013

.SYNOPSIS...
-- Changed Discussion --
DRY CANADIAN AIR WILL PREVAIL ACROSS THE REGION THROUGH THE MEMORIAL
DAY WEEKEND. A WARMING TREND WILL BEGIN ON MONDAY...CONTINUING THROUGH
THE UPCOMING WEEK WHILE REMAINING DRY. DAYTIME TEMPERATURES MAY RISE
SLIGHTLY ABOVE NORMAL WEDNESDAY THROUGH FRIDAY.
-- End Changed Discussion --

&&

.NEAR TERM /UNTIL 6 AM SATURDAY MORNING/...
AS OF 1 AM SATURDAY...A BROAD AREA OF CANADIAN HIGH PRESSURE WILL
CONTINUE TO SLOWLY BUILD ACROSS THE AREA. THIS IS AN UNSEASONABLY
CHILLY AIRMASS. TEMPS AT 850 MB WILL DROP TO AROUND 5 DEGREES
CELSIUS.

THE SKY WILL BE CLEAR THROUGH THE NIGHT...BUT THE BOUNDARY LAYER
WILL FIND IT DIFFICULT TO COMPLETELY DECOUPLE OVERNIGHT. THUS...
RADIATIONAL COOLING WILL BE TEMPERED BY A MAINLY LIGHT NORTH WIND.
DEWPOINTS...INDICATIVE OF THE VERY DRY AIR IN PLACE...WILL DROP INTO
THE MID AND UPPER 30S. THUS...THERE IS PLENTY OF OPPORTUNITY FOR
TEMPS TO DROP TO NEAR RECORD LOWS AND WE ARE INDEED FORECASTING
RECORD LOWS FOR MANY LOCATIONS. MY ONLY CONCERN IS THAT WE MAY NOT
FULLY REALIZE THE CHILL OF THIS AIRMASS...AT LEAST TONIGHT...GIVEN
THE LACK OF A FULLY DECOUPLED BOUNDARY LAYER. THEREFORE...WILL KEEP
FORECAST LOWS IN THE MID AND UPPER 40S AND THIS IS MORE OR LESS IN
LINE WITH CONSENSUS.

THE RECORD LOW AT ILM...50 AND WE ARE FORECASTING A LOW OF 48.
THE RECORD LOW AT FLO...48 AND WE ARE FORECASTING A LOW OF 47.
THE RECORD LOW AT CRE...47 AND WE ARE FORECASTING A LOW OF 49.

&&

.SHORT TERM /6 AM SATURDAY MORNING THROUGH SUNDAY NIGHT/...
AS OF 3 PM FRIDAY...SURFACE HIGH PRESSURE RIDGING DOWN FROM THE
NORTH AND BROAD CYCLONIC FLOW WITHIN A LONGWAVE UPPER TROUGH CREATES
COOL AND DRY CONDITIONS FOR THE WKND. WHILE THE WKND WILL BE
PLEASANT WITH MOSTLY SUNNY SKY CONDITIONS OTHER THAN SOME INCREASED
MID LEVEL CLOUD COVER BENEATH A WEAK SHORTWAVE LATE SAT
NIGHT...TEMPS WILL STRUGGLE TO 4-8 DEGREES BELOW CLIMO FOR LATE MAY.
STRONGER CAA SATURDAY WILL KEEP MAX TEMPS ONLY IN THE MID 70S EVEN
WITH FULL SUNSHINE. A WEAK SURFACE TROUGH ASSOCIATED WITH THE
PASSING VORT WILL TURN WINDS BRIEFLY TO THE NORTH SAT NIGHT...BUT A
MORE WESTERLY COMPONENT WILL DEVELOP SUNDAY WHICH EASES THE CAA AND
HELPS TEMPS RISE TO NEAR 80. LIGHT WINDS IN THE COOL/DRY AIR MASS
WILL PERMIT DECENT RADIATIONAL COOLING SAT NIGHT...WITH MINS FALLING
TO 10+ DEGREES BELOW NORMAL...UPPER 40S IN THE COOLER SPOTS TO
AROUND 50 EVERYWHERE ELSE. HIGH PRESSURE DRIFTING OFFSHORE LATE IN
THE PERIOD CREATES SOME WARMER SOUTHERLY WINDS SUNDAY NIGHT...AND
MINS FALL ONLY INTO THE LOW/MID 50S BY MONDAY MORNING.

&&

.LONG TERM /MONDAY THROUGH FRIDAY/...
AS OF 3 PM FRIDAY...MOST OF THE COUNTRY WILL REMAIN FAIRLY
ACTIVE THROUGH THE PERIOD WITH THE NOTABLE EXCEPTION OF THE
SOUTHEAST...WHERE MID LEVEL RIDGING WILL DOMINATE ESPECIALLY LATE
IN THE EXTENDED FORECAST.

WPC FAVORS THE ECMWF WHICH SHOWS AN ACTIVE MID LEVEL PATTERN ACROSS
THE SOUTHWEST WITH A MEANDERING CLOSED LOW AND BAROCLINIC ZONE
EXTENDING WEST TO EAST WELL TO OUR NORTH. THE ONLY POPS FOR OUR AREA
ARE SLIGHT CHANCE VALUES LATE MONDAY ACROSS NORTHERN AREAS AS A WARM
FRONT MOVES NORTH AND TUESDAY BEFORE MID LEVEL RIDGING BUILDS WHICH
WILL ALL BUT PUT A LID ON CONVECTION FOR WEDNESDAY THROUGH FRIDAY.
TEMPERATURE TRENDS REFLECT THE BUILDING RIDGE WITH AT OR JUST BELOW
SEASONAL NORMALS EARLY TRENDING TO ABOVE CLIMATOLOGY TUESDAY AND
WEDNESDAY WHERE THEY REMAIN THROUGH THE PERIOD.

&&

.AVIATION /06Z SATURDAY THROUGH WEDNESDAY/...
AS OF 06Z...EXPECT VFR AT ALL TERMS THROUGH THE VALID TAF PERIOD.
LIGHT NNW WINDS OVERNIGHT WILL INCREASE TO AROUND 10 KTS BY MID
MORNING. THE WINDS WILL SHIFT TO THE W/SW AFTER 18Z WITH HIGH
PRESSURE RIDGING INTO THE CAROLINAS. DRY AIR AND SUBSIDENCE WILL
INHIBIT CLOUD FORMATION DURING THE DAY. THE VERY WEAK GRADIENT OVER
OUR AREA AFTER 00Z SUNDAY SHOULD ALLOW THE WINDS TO BECOME CALM...
BUT THE LOW-LEVELS WILL BE TOO DRY FOR ANY FOG CONCERNS.

EXTENDED OUTLOOK...MORNING FOG POSSIBLE MONDAY THROUGH WEDNESDAY.
OTHERWISE VFR.

&&

.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 1 AM FRIDAY...SMALL CRAFT SHOULD EXERCISE CAUTION IS IN EFFECT
THROUGH 5 AM. AS HIGH PRESSURE BUILDS SLOWLY ACROSS THE AREA FROM
THE NW...DRY AND COOL AIR WILL CONTINUE TO SURGE ACROSS THE WATERS
ON NORTH WINDS. THESE WINDS WILL RANGE FROM 15 TO 20 KT WITH GUSTS
UP TO 25 KT OVERNIGHT. SEAS WILL GENERALLY BE 2 TO 4 FT...BUT UP TO
5 FT ACROSS THE OUTERMOST NORTHERN WATERS WHERE THE FETCH WILL BE
GREATEST.

SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/...
AS OF 3 PM FRIDAY...SLIGHTLY PINCHED GRADIENT AHEAD OF AN
ADVANCING HIGH PRESSURE AT THE START OF THE PERIOD WILL CREATE N/NW
WINDS OF 10-15 KTS EARLY SATURDAY BEFORE THE HIGH MOVES OVERHEAD
CAUSING MUCH WEAKER WIND SPEEDS. WINDS BECOME NW LESS THAN 10 KTS
SAT NIGHT INTO SUNDAY...BEFORE VEERING TO THE SE AT LESS THAN 10 KTS
SUNDAY NIGHT WHEN HIGH PRESSURE MOVES OFFSHORE. COMBINATION OF LIGHT
WINDS AND A WEAK 2FT/8SEC SE SWELL WILL KEEP WAVE AMPLITUDES LOW
THROUGH THE PERIOD...1-3 FT...HIGHEST EARLY SATURDAY.

LONG TERM /MONDAY THROUGH WEDNESDAY/...
AS OF 3 PM FRIDAY...THE MARINE COMMUNITY CAN EXPECT A
SUMMERTIME PATTERN THROUGH THE PERIOD WITH SOUTH TO OCCASIONALLY
SOUTHWEST WINDS. WIND SPEEDS WILL HOVER AROUND 10-15 KNOTS FOR
MOST OF THE PERIOD WITH THE HIGHER END TUESDAY AS THE GRADIENT
INCREASES COURTESY OF A WAVE MOVING BY WELL TO THE NORTH. SEAS ARE
REPRESENTATIVE OF A SUMMER PATTERN AS WELL WITH 2-3 FEET WITH
MOSTLY SHORTER PERIOD WIND WAVES.

&&

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

&&

$$

NEAR TERM...RJD/8
SHORT TERM...JDW
LONG TERM...SHK
AVIATION...BJR/8