-- Discussion containing changed information from previous version are highlighted. --
000
FXUS62 KILM 170108
AFDILM

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE WILMINGTON NC
908 PM EDT THU MAY 16 2013

.SYNOPSIS...
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WARM TEMPERATURES WILL CONTINUE INTO EARLY NEXT WEEK AS BERMUDA HIGH
PRESSURE REMAINS ANCHORED OFFSHORE. A MID LEVEL DISTURBANCE WILL
BRING A CHANCES OF SHOWERS AND THUNDERSTORMS OVER THE WEEKEND INTO
EARLY NEXT. DRIER WEATHER IS EXPECTED THROUGH THE MIDDLE OF NEXT
WEEK.
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&&

.NEAR TERM /UNTIL 6 AM FRIDAY MORNING/...
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AS OF 9 PM THURSDAY...A MILD EVENING AND OVERNIGHT PERIOD UNDERWAY
AS SOUTHERLY FLOW AROUND HIGH PRESSURE OFFSHORE PREVAILS. AIDING
THE MILD REGIME ARE MIDDLE AND HIGH CLOUDS AHEAD OF AN IMPULSE
EVIDENT IN VAPOR ANIMATIONS MOVING E OVER THE CENTRAL CAROLINAS.
CONVECTION WAS CONFINED MAINLY IN THE APPALACHIANS THIS EVENING.

PARTIAL BUT NOT FULL CLEARING IS EXPECTED OVERNIGHT AS A SERIES
OF UPSTREAM DISTURBANCES ALOFT PRODUCE VARYING DEGREES OF HIGH
CLOUDINESS. THIS COUPLED WITH SW LOW-LEVEL WIND FLOW OVERNIGHT
SHOULD ALLOW A SLOW DROPPING TEMPERATURE TREND WITH LOWS IN THE
MIDDLE AND UPPER 60S ALONG THE COAST BY DAYBREAK FRIDAY AND LOW
TO MIDDLE 60S INLAND. LATEST LAV GUIDANCE HAS MINS A FEW DEGREES
WARMER THAN FORECAST AND A FEW TWEAKS UPWARD ARE PLANNED FOR THE
OVERNIGHT UPDATE TO MIN TEMPS. NO OTHER CHANGES PLANNED.
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&&

.SHORT TERM /6 AM FRIDAY MORNING THROUGH SATURDAY NIGHT/...
AS OF 3 PM THURSDAY...A BERMUDA RIDGE WILL KEEP IT WARM ACROSS THE
FORECAST AREA THIS PERIOD. A PIEDMONT TROUGH WILL REMAIN IN PLACE.
A BACKDOOR COLD FRONT WILL DRIFT SOUTH AND SHOULD BE NEAR THE
ONSLOW-PENDER COUNTY LINE FRI NIGHT. THIS FRONT IS EXPECTED TO
BECOME INCREASINGLY ILL-DEFINED AS IT STALLS OUT COMPLETELY. THE
FRONT SHOULD TEND TO LIFT BACK TO THE N AS THE FLOW BECOMES
PROGRESSIVELY SW...AND S BELOW 5 KFT ON SAT. A WEAK MID-LEVEL
SHORTWAVE WILL APPROACH THE AREA LATE SAT AND SAT NIGHT.

A SHARP SEABREEZE FRONT IS EXPECTED TO MOVE SLOWLY INLAND ON
FRI...RETARDED SOMEWHAT BY THE RATHER DEEP...BUT WEAK...WESTERLY
FLOW. THE SEABREEZE SHOULD MAKE MUCH BETTER PROGRESS INLAND ON SAT
GIVEN THE PREVAILING FLOW.

IN TERMS OF HOW THIS WILL AFFECT OUR SENSIBLE WEATHER. IT WILL
REMAIN WARM THROUGH THE PERIOD. FRI SHOULD BE WARMER THAN SAT GIVEN
THERE SHOULD BE AT LEAST A LITTLE LESS CLOUD COVER AND CONVECTION
SHOULD BE ISOLATED. EITHER WAY...BOTH DAYS WILL BE WELL UP IN THE
80S. A FEW 90 DEGREE READINGS ARE POSSIBLE FRI...ESPECIALLY ACROSS
PORTIONS OF THE PEE DEE. THE BEACHES AND NEARBY LOCATIONS WILL BE
WARMEST ON FRI...PERHAPS REACHING 80 DEGREES. NIGHTTIME TEMPS WILL
ALSO BE ABOVE NORMAL...MID AND UPPER 60S THROUGHOUT.

GIVEN SUBSIDENT FLOW WILL LINGER AND DRY AIR WILL BE TOUGH TO
DISPLACE FRI...WILL INCLUDE ONLY SLIGHT CHANCE POPS WITH A SLIGHTLY
BETTER CHANCE FRI EVE ACROSS PENDER AND BLADEN COUNTIES WHICH WILL
BE IN CLOSEST PROXIMITY TO THE BACKDOOR FRONT. A MORE SOUTHERLY FLOW
ON SAT AND THE APPROACH OF A WEAK SHORTWAVE TROUGH SHOULD ALLOW FOR
MORE IN THE WAY OF CONVECTION. CAPE VALUES BECOME SIGNIFICANT...IN
EXCESS OF 1500 TO 2000 J/KG...INDICATIVE OF GOOD INSTABILITY.
HOWEVER...MID-LEVEL LAPSE RATES ARE BELOW 7 DEG C/KM WHICH SHOULD
HINDER MORE ROBUST UPDRAFTS. STILL...WOULD EXPECT CONVECTION TO
DEVELOP ALONG THE INLAND PENETRATING SEABREEZE AND THE PIEDMONT
TROUGH. COVERAGE AND STRENGTH OF THE CONVECTION SHOULD BE ENHANCED
BY THE WEAK MID-LEVEL SUPPORT...ESPECIALLY ALONG AND W OF INTERSTATE
95. WILL CARRY UP TO LOW-END LIKELY POPS ACROSS THE WESTERN FRINGES
OF OUR FORECAST AREA SAT AFTERNOON AND EVE...WITH POPS DECREASING TO
SLIGHT CHANCE CLOSER TO THE COAST.

&&

.LONG TERM /SUNDAY THROUGH THURSDAY/...
AS OF 300 PM THURSDAY...SUMMERTIME PATTERN CONTINUES WITH BERMUDA
HIGH PRESSURE ANCHORED OFFSHORE PUMPING WARM AND MORE HUMID AIR INTO
THE REGION. WHILE THIS TYPICALLY SUPPORTS TEMPS ABOVE CLIMO WITH
DIURNAL CONVECTION...THE BEST CHANCES FOR TSTMS WILL BE SUN/MON.
UPPER IMPULSE ROTATING SLOWLY AROUND BUILDING 5H RIDGE WILL TRACK
NEARLY OVERHEAD SUN AND MON. THIS OCCURS IN AN ENVIRONMENT
CHARACTERIZED BY PWATS APPROACHING 1.8 INCHES...OR NEARLY 2 SD`S
ABOVE NORMAL FOR MID-MAY. THE COMBINATION OF THE UPPER
FORCING...SIGNIFICANT INSTABILITY OF 1000-2000 J/KG...SEA BREEZE
BOUNDARY AND PIEDMONT TROUGH...AND DEWPOINTS RISING INTO THE MID
60S...SUPPORTS WIDESPREAD CONVECTION BOTH SUN AND MON AFTN. ML LAPSE
RATES WILL BE ONLY MARGINAL HOWEVER...5-6 C/KM...SO WHILE CONVECTION
SHOULD BE PRETTY WIDESPREAD...SEVERE CONVECTION APPEARS UNLIKELY.

BY TUESDAY...UPPER VORT SWINGS OFFSHORE LEAVING SOME SUBSIDENCE
BEHIND IT IN CONJUNCTION WITH BUILDING 1000-500MB THICKNESSES. WHILE
COLUMN REMAINS QUITE MOIST...OVERALL CONVECTIVE COVERAGE WILL BE
DECREASED ON TUESDAY...AND EVEN MORESO WED/THU WITH DRIER AIR
WORKING INTO THE REGION AND SUBSIDENCE INCREASING DUE TO THE
BUILDING MID LEVEL RIDGE.

TEMPS DURING THE PERIOD WILL BE AROUND...TO SLIGHTLY ABOVE CLIMO
EACH DAY. EXPECT HIGHS IN THE LOW/MID 80S WITH LOWS IN THE LOW/MID
60S. A SLIGHT WARM UP MAY OCCUR DURING THE MIDDLE OF NEXT WEEK.

&&

.AVIATION /01Z FRIDAY THROUGH TUESDAY/...
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AS OF 01Z...VFR AT ALL TERMS THIS EVENING WITH SCT/BKN CIRRUS AND
SOUTHWEST WINDS AOB 10 KTS. MID/HIGH CLOUDS WILL CONTINUE MOVING
OVER THE CWA TONIGHT AS THE WINDS DIMINISH TO 5 KTS OR LESS.
LOW-LEVEL WIND PROFILES DO NOT SUPPORT FOG FORMATION...BUT CANNOT
RULE OUT TEMPO MVFR VSBYS AT KLBT/KFLO WHERE THE WINDS MAY BECOME
CALM/LIGHT JUST BEFORE DAYBREAK. EXPECT VFR ON THURSDAY WITH SOME
SCT CU DURING THE DAY AND SOUTHWEST WINDS AOB 10 KTS. ALONG THE
COAST...WINDS WILL BECOME MORE SOUTHERLY BY MID-AFTERNOON AS THE SEA
BREEZE PUSHES THROUGH THESE TERMS.

EXTENDED OUTLOOK...CHANCE OF AFTN SHOWERS/TSTMS SATURDAY THROUGH
MONDAY...OTHERWISE VFR.
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&&

.MARINE...
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NEAR TERM /THROUGH TONIGHT/...
AS OF 9 PM THURSDAY...SW WINDS WILL DECREASE A BIT OVERNIGHT AS A
LOW PRESSURE SYSTEM PASSING OVER NEW ENGLAND LIFTS FARTHER TO THE
NE. THIS WILL LEAVE A SW RETURN FLOW AROUND 10 TO 15 KTS HEADING
INTO THE MORNING. SEAS MAINLY IN THE 2 TO 4 FT RANGE IN A MIX OF SSW
WIND-CHOP AND WEAK LONGER PERIOD SE WAVES. NO TSTMS OR FOG CONCERNS
OVER THE 0-20NM WATERS THROUGH DAYBREAK FRIDAY.

SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/...
AS OF 3 PM THURSDAY...WINDS WILL REMAIN FROM THE SSW TO SW THROUGH
THE PERIOD. THE PROXIMITY OF THE BERMUDA RIDGE SHOULD KEEP WINDS 15
KT OR LESS. SEAS WILL RANGE FROM 2 TO 4 FT. THE BACKDOOR COLD FRONT
IS EXPECTED TO STALL JUST N OF THE WATERS FRI NIGHT...BEFORE MOVING
BACK TO THE N.

LONG TERM /SUNDAY THROUGH TUESDAY/...
AS OF 300 PM THURSDAY...RETURN FLOW AROUND OFFSHORE BERMUDA HIGH
PRESSURE CREATES PERSISTENT S/SW WINDS OVER THE WATERS. WHILE
MINOR DIURNAL FLUCTUATIONS IN DIRECTION/SPEED ARE LIKELY DURING
THE PERIOD...WINDS WILL BE PREDOMINANTLY 10-15 KTS EACH DAY DURING
THE EXTENDED. EVEN THOUGH E/SE SWELL WILL SLOWLY GROW IN AMPLITUDE
WITH AN INCREASING PERIOD DURING THE EXTENDED...TO
2-3FT/10SEC...WAVES WILL STILL BE PRIMARILY WIND-WAVE DOMINATED.
SEAS OF 2-4 FT CAN BE EXPECTED EACH DAY...WITH A S/SW WIND WAVE
OVERLAYING THE E/SE SWELL.
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&&

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

&&

$$

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