-- Discussion containing changed information from previous version are highlighted. --
000
FXUS62 KILM 201012
AFDILM

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE WILMINGTON NC
612 AM EDT THU JUN 20 2013

.SYNOPSIS...
HIGH PRESSURE WILL NOSE IN FROM THE NORTH...KEEPING A FRONT STALLED
OUT TO OUR SOUTH TODAY. THIS SHOULD ALLOW SOME DRIER AIR TO FILTER
INTO THE AREA FROM THE NORTH. THE LINGERING FRONT WILL NUDGE BACK TO
THE NORTH DURING FRIDAY AND THROUGH THE WEEKEND. SUMMER PATTERN
SETS UP NEXT WEEK WITH BERMUDA HIGH AND PIEDMONT TROUGH BECOMING
THE DOMINANT SURFACE FEATURES.

&&

.NEAR TERM /THROUGH TONIGHT/...
-- Changed Discussion --
AS OF 6 AM THURSDAY...WATER VAPOR IMAGERY SHOWS THE DRY AIR HAS MADE
A NICE SURGE TO THE COAST THIS MORNING IN THE WAKE OF A WAVE OF LOW
PRESSURE AND THE SHOWERS THAT WERE OCCURRING ACROSS PORTIONS OF THE
AREA OVERNIGHT HAVE DRIED UP. THE CONVECTION HAS NOW SHIFTED
OFFSHORE IN CLOSER PROXIMITY TO THE STALLED FRONT.

THE FORECAST AREA WILL REMAIN A BATTLEGROUND TODAY WITH A MOISTURE
LADEN AIRMASS POISED TO OUR S AND E AND A DRIER AIRMASS POSITIONED
TO OUR N. THE FRONT REMAINS RATHER SHALLOW AND HAS NOT BEEN ABLE TO
PUSH THE DEEPER MOISTURE THAT FAR TO OUR SOUTH AND EAST.

A NORTHEAST SURGE HAS WORKED ITS WAY INTO THE FORECAST AREA AND WITH
THAT...DEWPOINTS HAVE BEEN TRENDING SLOWLY LOWER WITH TIME. IT LOOKS
AS THOUGH THE DRY AIRMASS MAY HOLD OUT ACROSS MOST OF OUR FORECAST
AREA THIS PERIOD AND HAVE DECIDED TO KEEP POPS BELOW THRESHOLD
ACROSS THE NORTHERN PEE DEE AND MOST OF NORTH CAROLINA...EXCEPT FOR
THE SOUTHERN PORTIONS OF THE CAPE FEAR REGION. IN THESE AREAS...THE
INFLUX OF DRY AIR SHOULD BE MORE DIFFICULT TO OVERCOME AND A
DEVELOPING WARM CAPPING INVERSION AROUND 15 KFT DOES STRENGTHEN
THROUGH THE DAY. THESE AREAS DRY OUT FURTHER TONIGHT AS EVIDENCED BY
THE FALLING PRECIPITABLE WATER VALUES.

FOR POINTS S AND E OF THE AFOREMENTIONED LINE...THE FORECAST WILL
SHOW A POP GRADIENT WITH THE HIGHEST RISK FOR SHOWERS ACROSS THE
SOUTH SANTEE RIVER AREA TO GEORGETOWN AND THE SOUTHERNMOST GRAND
STRAND. WE ARE NOT LOOKING FOR ANY HEAVY RAIN TODAY AND WITH MIXED
LAYER CAPE VALUES GENERALLY 500 J/KG OR LESS...WILL OPT NOT TO
MENTION THUNDERSTORMS. TONIGHT...MOISTENING TAKES PLACE ABOVE 10
KFT...BUT OTHERWISE THE PROFILE IS NOT CONDUCIVE FOR MEASURABLE
PRECIPITATION...ALTHOUGH IT IS SUPPORTIVE OF MORE CLOUD COVER THAN
AREAS FURTHER INLAND. WILL SHOW SLIGHT CHANCE POPS IN THE EVE
TRENDING EVEN LOWER DURING THE NIGHT AND EXPECT MOST OF THE
PRECIPITATION WILL BE CONFINED TO AREAS OFFSHORE IN CLOSER
PROXIMITY TO THE FRONT.

AN E TO NE LOW-LEVEL FLOW WILL HELP TO MODERATE TEMPS TODAY SO EVEN
WHERE MORE SUNSHINE DOES PREVAIL...TEMPS SHOULD FALL SHORT OF NORMAL
FOR LATE JUNE. WILL SHOW HIGHS IN THE LOWER TO MID 80S...COOLEST
ALONG THE COAST WHERE SOME BEACH COMMUNITIES WILL DO WELL TO REACH
80 DEGREES. TONIGHT...WINDS ARE NOT EXPECTED TO FULLY DECOUPLE AND
SO EVEN IN AREAS WHERE CLOUDS DO NOT FILL BACK IN...RADIATIONAL
COOLING IS NOT EXPECTED TO BE SIGNIFICANT. STILL...LOWS WILL BE JUST
BELOW NORMAL IN MOST AREAS...MID TO UPPER 60S.
-- End Changed Discussion --

&&

.SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/...
AS OF 3 AM THURSDAY...COLD FRONT STALLED OFF THE COAST SLOWLY
MOVES CLOSER TO THE COAST FRI AND SAT AS IT GRADUALLY WEAKENS.
BOTH GFS AND ECMWF HAVE DEEP MOISTURE MOVING ON SHORE FRI INTO SAT
AS THE BOUNDARY APPROACHES THE COAST. PRECIP WILL BE CONFINED TO
THE IMMEDIATE COAST EARLY FRI AS DEEP DRY AIR INLAND HOLDS STRONG.
OVER TIME SOUTHWEST FLOW ALOFT AND EAST TO SOUTHEAST FLOW IN THE
LOW AND MID LEVELS PUSH DEEPER MOISTURE FARTHER INLAND. PRECIP FRI
WILL BE DRIVEN MORE BY DIURNAL INSTABILITY AS THE SURFACE
BOUNDARY REMAINS OFF THE COAST. INLAND AREAS MAY NOT SEE PRECIP
UNTIL MID TO LATE AFTERNOON...ONCE DEEPER MOISTURE ARRIVES. ALONG
THE COAST THINK CONVECTION SHOULD BE GOING BY LATE MORNING AS VERY
LITTLE HEATING WILL BE NEEDED. AS CONVECTION IS BEING DRIVEN BY
DIURNAL INSTABILITY MOST OF THE ACTIVITY SHOULD WEAKEN AND
DISSIPATE FRI EVENING. EXCEPTION MAY BE ALONG THE COAST WHERE
SHOWERS JUST OFF THE COAST MAY BRUSH COASTAL COUNTIES.

SAT THE FRONT/TROUGH SLOWLY MOVES ONSHORE AS IT STARTS TO WEAKEN.
COMBINATION OF DIURNAL INSTABILITY AND WEAK CONVERGENCE ALONG THE
BOUNDARY SHOULD LEAD TO ANOTHER ROUND OF AFTERNOON SHOWERS AND
THUNDERSTORMS. LOSS OF HEATING SAT EVENING SHOULD ONCE AGAIN LEAD TO
A DECREASE IN CONVECTION AS VERY LITTLE WILL REMAIN OF THE COASTAL
TROUGH. HEAVY RAIN WILL BE AN ISSUE BOTH FRI AND SAT...THOUGH
PRESENCE OF SURFACE BOUNDARY DOES GIVE A SLIGHT NOD TO SAT. DEEP
MOISTURE...PRECIPITABLE WATER VALUES AT OR ABOVE 2 INCHES...AND
STORM MOTIONS OF 5 TO 10 KT IN CONJUNCTION WITH DEEP WARM CLOUD
LAYER ARE ALL CONTRIBUTE TO HIGH PRECIPITATION EFFICIENCY.
FLOODING COULD BE A PROBLEM FOR AREAS THAT HAVE RECEIVED RAINFALL
RECENTLY BUT WIND FIELDS DO NOT SUGGEST A BACK BUILDING
THREAT...THOUGH THERE MAY BE POTENTIAL FOR TRAINING STORMS.

TEMPERATURES WILL REMAIN BELOW CLIMO THROUGH THE PERIOD. HIGHS IN
MANY AREAS WILL REMAIN IN THE LOW TO MID 80S. LOWS WILL RUN A
LITTLE CLOSER TO CLIMO...THOUGH STILL UNDER.

&&

.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
AS OF 3 AM THURSDAY...NEXT WEEK WILL SEE THE RETURN OF A MORE
TYPICAL SUMMER PATTERN ACROSS THE SOUTHEAST. MEDIUM RANGE GUIDANCE
IS INSISTENT ON LINGERING DEEP MOISTURE ASSOCIATED WITH DISSIPATING
COASTAL TROUGH IN THE AREA SUN AND MON. GFS CONTINUES TO SHOW
HIGHER AMOUNTS OF MOISTURE THAN THE ECMWF BUT DIFFERENCES ARE LESS
THAN BEFORE. BERMUDA HIGH AND PIEDMONT TROUGH BECOME THE MAIN
SURFACE FEATURES NEXT WEEK WHILE ALOFT WEAK 5H RIDGE BUILDS OVER
THE SOUTHEAST. BOTH GFS AND ECMWF AMPLIFY MID LEVEL RIDGING OVER
THE WESTERN CONUS WHICH STARTS TO SQUASH WEAK EAST COAST RIDGING
AS EARLY AS THE MIDDLE OF NEXT WEEK.

DEEPER MOISTURE IN THE AREA SUN/MON IN CONJUNCTION WITH DIURNAL
HEATING SUGGEST CHANCE POP FOR BOTH SUN AND MON DESPITE WEAK 5H
RIDGE BUILDING OVERHEAD. RIDGE STARTS TO BREAK DOWN TUE/WED WITH
WEAKENING MID LEVEL SUBSIDENCE ALLOWING FOR A MORE ACTIVE SEA
BREEZE...WHICH ALSO WARRANTS CHANCE POP. TEMPS SLIGHTLY BELOW CLIMO
AT THE START OF THE PERIOD SLOWLY CLIMB ABOVE CLIMO THROUGH THE
PERIOD.

&&

.AVIATION /06Z THURSDAY THROUGH MONDAY/...
AS OF 06Z...MVFR/IFR CIGS ARE EXPECTED EARLY THIS MORNING AS
ABUNDANT LOW-LEVEL MOISTURE REMAINS IN PLACE ACROSS THE CWA. IFR
SEEMS MOST LIKELY TO OCCUR BETWEEN 09-12Z AT THE COASTAL TERMS...
WHILE THE LATEST GUIDANCE SUGGESTS KFLO/KLBT WILL REMAIN MVFR.
LOWERED CIGS MAY LINGER ALONG THE COAST THRU THE MORNING HOURS WITH
THE STALLED FRONT NEARBY AND CONTINUING SHOWERS OFFSHORE. CONDITIONS
SHOULD BECOME VFR AT ALL TERMS BY THE AFTN WITH E/NE WINDS 10-12
KT. HAVE INCLUDED VCSH FOR KMYR/KCRE DURING THE DAY BASED ON THE
POSITIONING OF THE FRONT AND THE POTENTIAL FOR PASSING -SHRA TO CLIP
THESE SITES. OTHERWISE...VFR SHOULD PERSIST THRU THE AFTN/EVENING
HOURS WITH WINDS BECOMING AOB 5 KTS AFTER SUNSET.

EXTENDED OUTLOOK...SLIGHT CHANCE OF SHOWERS FRIDAY THRU SUNDAY AS A
STALLED FRONTAL BOUNDARY LINGERS NEAR THE COAST. VFR ON MONDAY.

&&

.MARINE...
-- Changed Discussion --
NEAR TERM /THROUGH TONIGHT/...
AS OF 6 AM THURSDAY...A NE SURGE IS UNDERWAY ACROSS THE WATERS
RESULTING IN A SMALL CRAFT SHOULD EXERCISE CAUTION HEADLINE. EXPECT
NE WINDS OF 15 TO AROUND 20 KT FOR MUCH OF THE DAY WITH SEAS OF 4 TO
5 FT. NE WINDS WILL PERSIST TONIGHT AS THE STALLED FRONT REMAINS
OFFSHORE. WINDS SHOULD EASE A KT OR TWO AND WITH THAT...3 TO 4 FT
WAVE HEIGHTS SHOULD BE MOST COMMON ALTHOUGH 5 FT SEAS ARE STILL
EXPECTED ACROSS THE OUTER WATERS. ALTHOUGH THE WAVE SPECTRUM WILL BE
DOMINATED BY SHORTER PERIOD WIND WAVES...A 9 SECOND SE SWELL WILL
CONTINUE.

SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/...
AS OF 3 AM THURSDAY...NORTHEAST FLOW WILL BE DECREASING IN STRENGTH
FRI AS SURFACE BOUNDARY EAST OF THE WATERS MOVES CLOSER AND SURFACE
HIGH RETREATS A LITTLE FARTHER NORTH. SPEEDS DROP UNDER 10 KT AS
EARLY AS FRI AFTERNOON AND BECOME MORE EASTERLY. LIGHT WINDS WILL
MAINTAIN AN EASTERLY COMPONENT THROUGH THE END OF THE PERIOD BUT
SHOULD BECOME MORE EASTERLY AND THEN SOUTHEASTERLY SAT AS WEAK
COASTAL TROUGH MOVES INLAND AND SEA BREEZE DEVELOPS. SEAS 3 TO 4
FT FRI DECREASE TO 2 TO 3 FT ON SAT AND UNDER 3 FT SAT NIGHT.

LONG TERM /SUNDAY THROUGH MONDAY/...
AS OF 3 AM THURSDAY...SOUTHEAST FLOW AT THE START OF THE PERIOD WILL
BECOME SOUTHWEST SUN AS BERMUDA HIGH BECOMES THE DOMINANT FEATURE.
SPEEDS WILL REMAIN UNDER 10 KT WITH WINDS VEERING FROM SOUTHEAST SUN
MORNING TO SOUTHWEST BY MON MORNING. WEAK PIEDMONT TROUGH MON LEADS
TO A SLIGHT INCREASE IN SPEEDS FOR THE SECOND HALF OF THE PERIOD.
SPEEDS LATER MON WILL EXCEED 10 KT BUT REMAIN UNDER 15 KT. SEAS
WILL RUN 2 TO 3 FT THROUGH THE PERIOD.
-- End Changed Discussion --

&&

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

&&

$$

NEAR TERM...RJD
SHORT TERM...III
LONG TERM...III
AVIATION...BJR/RJD