-- Discussion containing changed information from previous version are highlighted. --
000
FXUS62 KILM 181750
AFDILM

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE WILMINGTON NC
150 PM EDT TUE JUN 18 2013

.SYNOPSIS...
WARM AND HUMID CONDITIONS WILL PREVAIL AHEAD OF AN APPROACHING COLD
FRONT...WHICH WILL MOVE THROUGH THE AREA EARLY ON WEDNESDAY. HIGH
PRESSURE WILL BUILD IN FROM THE NORTH THEREAFTER...WITH A DRYING
TREND BEGINNING TOWARDS THE END OF THE WEEK. THE DRYING TREND WILL
LAST INTO EARLY NEXT WEEK.

&&

.NEAR TERM /THROUGH TONIGHT/...
AS OF 12:30 PM TUESDAY...NO CHANGES TO THE FORECAST WITH THE
LATEST UPDATE. PREVIOUS DISCUSSION FOLLOWS:

ANALYSIS OF MORNING SOUNDINGS AND A LOOK AT THE LATEST SYNOPTIC
SITUATION CONFIRMS EARLIER THINKING THAT CONVECTION IS LIKELY TO
DEVELOP THIS AFTERNOON AND LAST WELL INTO THE EVENING HOURS.
STRONGEST CONVECTION POSSIBLE LATE THIS AFTERNOON AND EARLY
EVENING AS A VORTICITY MAX TRANSITS THE AREA FROM WEST TO EAST.
PREVIOUS DISCUSSION FOLLOWS:

A COLD FRONT WILL APPROACH FROM THE NW TODAY AND MOVE INTO THE
AREA TONIGHT. IN ADVANCE OF THE FRONT EXPECT TO SEE SCATTERED TO
NUMEROUS SHOWERS AND THUNDERSTORMS...PARTICULARLY DURING THE
AFTERNOON AND EVENING HOURS. ONCE CURRENT ACTIVITY CLEARS THE
COAST...PLAN ON CHC POPS THROUGH THE PERIOD EXCEPT FOR LIKELY POPS
FROM ABOUT MIDDAY INTO THE EVENING HOURS. MAX TEMPERATURES TODAY
SHOULD REACH THE MID 80S WITH LOWS TONIGHT WITHIN A COUPLE DEGREES
OF 70.

&&

.SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/...
AS OF 3 AM TUESDAY...FRONT IN THE AREA AT THE START OF THE PERIOD
WILL BE PUSHED FARTHER EAST BY WESTERLY FLOW ALOFT AND SURFACE HIGH
RIDGING DOWN THE COAST DURING THE PERIOD. GFS/WRF/ECMWF ALL SHOW
DRIER MID LEVEL AIR MOVING INTO THE REGION AS EARLY AS WED AFTERNOON
BUT MORE LIKELY WED EVENING. SOUNDINGS SHOW DEVELOPMENT OF MID LEVEL
STABLE LAYER AS SUBSIDENCE DEVELOPS BEHIND EXITING 5H TROUGH AXIS.
AS A RESULT PRECIPITABLE WATER VALUES ARE FORECAST TO DROP UNDER 1.5
INCH BY EVENING LIMITING PRECIP COVERAGE TO EARLIER IN THE DAY.
STILL HOLDING ONTO CHC POP BUT FURTHER REDUCTION MAY BE REQUIRED.

ALTHOUGH THERE WILL BE DRY AIR IN THE MID LEVELS WED INTO THU THE
HIGH BUILDING IN FROM THE NORTH WILL RESULT IN LOW LEVEL NORTH TO
NORTHEAST FLOW. LOW LEVEL MOISTURE UNDER MID LEVEL INVERSION COULD
TRANSLATE TO INCREASED CLOUD COVER WED AND EARLY THU.

LOW LEVEL FLOW BECOMES EAST AND POSSIBLY SOUTHEAST THU INTO THU
NIGHT. AT THE SAME TIME FLOW ALOFT VEERS TO NORTH-NORTHEAST IN
RESPONSE TO WEAK 5H RIDGE BUILDING OVER THE CENTRAL US. THIS HELPS
WEAKEN THE CAP WHICH MAY ALLOW FOR SOME ISOLATED CONVECTION BUT MID
LEVEL DRY AIR REMAINS A BIG OBSTACLE. WILL CARRY SLIGHT CHC POP THU
AFTERNOON BUT THIS MAY BE GENEROUS. LOSS OF HEATING SHOULD END
ANY PRECIP THREAT SO WILL CARRY NO MENTIONABLE POP THU NIGHT.
TEMPERATURES WILL BE NEAR TO SLIGHTLY BELOW CLIMO THROUGH THE
PERIOD.

&&

.LONG TERM /FRIDAY THROUGH TUESDAY/...
AS OF 3 AM TUESDAY...MID LEVEL RIDGING SHIFTS EAST DURING THE
PERIOD WHILE AT THE SURFACE ELONGATED HIGH MOVES SOUTH OF NEW
ENGLAND. SUBSIDENCE UNDER THE BUILDING RIDGE MAINTAINS DEEP DRY
AIR OVER THE CAROLINAS. FORECAST SOUNDINGS SHOW PWATS DROPPING
UNDER 1 INCH FRI MORNING AND REMAINING UNDER 1 INCH THROUGH THE
WEEKEND. ALTHOUGH THERE WILL BE A SEA BREEZE EACH AFTERNOON THINK
VERY LITTLE IF ANY CU WILL DEVELOP WITH PRECIP CHANCES BEING QUITE
LIMITED. LOW LEVEL AND UPPER LEVEL MOISTURE STARTS TO INCREASE ON
MON AS SURFACE HIGH SHIFTS TO THE MORE TYPICAL BERMUDA LOCATION
AND MID LEVEL RIDGE AXIS CONSOLIDATES OFF THE SOUTHEAST COAST.
INCREASE IN MOISTURE IS NOT ENOUGH TO WARRANT ANYTHING OTHER THAN
A SILENT POP BUT IS LIKELY TO RESULT IN AN INCREASE IN HIGH CLOUD
AS THE PERIOD ENDS. TEMPERATURES START OUT NEAR TO SLIGHTLY BELOW
CLIMO BUT STEADILY INCREASE THROUGH THE PERIOD AS MID LEVEL
RIDGING MOVES OVERHEAD AND SUBSIDENCE INCREASES.

&&

.AVIATION /18Z TUESDAY THROUGH SUNDAY/...
-- Changed Discussion --
AS OF 18Z...THIS AFTERNOON...SHOWERS DEVELOPED ALONG THE SEA BREEZE
NEAR KILM EARLIER BUT HAVE SINCE DISSIPATED. SW-WSW FLOW THROUGH THE
MID LEVELS SUGGESTS THE THE SEA BREEZE WILL NOT PENETRATE TOO MUCH
FURTHER INLAND. MODELS SUGGESTS THE SIGNIFICANT LIFT NEAR KILM WILL
SUBSIDE THIS AFTERNOON. WILL CONTINUE TO ONLY MENTION VCSH FOR THE
COASTAL TERMINALS THROUGH THE AFTERNOON. SHOULD SEE A CONTINUED LIFT
OF CLOUD BASES THUS DESPITE THE PROXIMITY OF THE SEA BREEZE BOUNDARY
RESULTING IN LOW VFR CIGS. OTHER SHOWERS/ISOLATED THUNDERSTORMS ARE
APPROACHING KFLO FROM THE WEST BUT CONVECTION IS NOT IMPRESSIVE.
WILL INDICATE VCTS AT KFLO/KLBT 21-22Z. CONFIDENCE IS MODERATE
SHOWERS/TSTMS WILL OCCUR 00-02Z. VCTS SHOULD DEVELOP AT THE COASTAL
TERMINALS 01-02Z WITH MODERATE CONFIDENCE OF SHOWERS/TSTMS 02-04Z.
PREDOMINATE MVFR/TEMPO IFR EXPECTED WITH THIS ACTIVITY.

CONVECTION WILL MOVE SOUTH OF THE TERMINALS AFTER MIDNIGHT. MVFR
CEILINGS WILL DEVELOP AS WINDS SHIFT TO THE NORTHWEST OVERNIGHT.
MVFR CEILINGS WILL LIFT TO VFR AT KFLO/KLBT SHORTLY AFTER
SUNRISE...BUT COULD PERSIST THROUGH THE END OF THE TAF VALID PERIOD
AS SHOWER/TSTMS REDEVELOP AT THE COASTAL TERMINALS.

EXTENDED OUTLOOK...SHOWERS AND THUNDERSTORMS LIKELY WEDNESDAY WITH
MVFR/TEMPO IFR POSSIBLE. VFR THURSDAY THROUGH SATURDAY.
-- End Changed Discussion --

&&

.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 12:30 PM TUESDAY...NO CHANGES TO THE FORECAST WITH THE
LATEST UPDATE. PREVIOUS DISCUSSION FROM EARLIER THIS MORNING
FOLLOWS:

EXPECT S TO SW WINDS OF 10 TO 15 KT TODAY TO INCREASE TO 15 TO 20
KT TONIGHT BEFORE DIMINISHING SLIGHTLY LATE AS THE FRONT NEARS THE
WATERS. SEAS OF 2 TO 3 FT EARLY TODAY WILL PEAK IN THE 3 TO 5 FT
RANGE THIS EVENING BEFORE SUBSIDING SLIGHTLY TOWARD DAY BREAK.

SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/...
AS OF 3 AM TUESDAY...COLD FRONT PUSHES EAST OF THE WATERS DURING
WED AS HIGH PRESSURE BUILDS IN FROM THEN NORTH. AS A RESULT LIGHT
OFFSHORE FLOW WILL VEER TO NORTH-NORTHEAST WED NIGHT INTO THU.
GRADIENT INCREASES THU AS THE HIGH BUILDS SOUTH...PUSHING
NORTHEAST FLOW AS HIGH TO 15 KT LATER THU AND THU NIGHT. OFFSHORE
FLOW WILL KNOCK SEAS FROM 3 TO 5 FT AT THE START OF THE PERIOD TO
2 TO 3 FT BY THU MORNING. INCREASE IN NORTHEAST FLOW THU AND THU
NIGHT WILL RESULT IN A MARGINAL INCREASE IN SEAS FOR THE SECOND
HALF OF THE PERIOD...3 TO 4 FT.

LONG TERM /FRIDAY THROUGH SATURDAY/...
AS OF 3 AM TUESDAY...HIGH PRESSURE NORTH OF THE WATERS WILL
REMAIN THE DOMINANT FEATURE THROUGH THE PERIOD. LACK OF GRADIENT
WILL KEEP SPEEDS UNDER 15 KT AND ALLOW FOR DAILY SEA BREEZE WITH
MORE OF AN ONSHORE WIND COMPONENT DEVELOPING NEAR SHORE. SEAS WILL
RUN 2 TO 4 FT THROUGH THE PERIOD.

&&

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

&&

$$

NEAR TERM...REK
AVIATION...MRR
MARINE...REK