Area Forecast Discussion
Issued by NWS Wilmington, NC

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FXUS62 KILM 161519
AFDILM

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE WILMINGTON NC
1119 AM EDT TUE SEP 16 2014

.SYNOPSIS...
A COLD FRONT WILL PUSH OFFSHORE LATE TONIGHT. HIGH PRESSURE WILL
EXTEND DOWN INTO THE CAROLINAS FROM THE NORTH BEHIND THIS
FRONT...PROVIDING FALL-LIKE WEATHER FOR THE REMAINDER OF THE WEEK.

&&

.NEAR TERM /THROUGH TONIGHT/...
AS OF 1100 AM TUESDAY...CONVECTION CONTINUES TO DEVELOP
OFFSHORE...BUT FEW IF ANY SHOWERS ACROSS THE EASTERN CAROLINAS LATE
THIS MORNING. WE SHOULD CONTINUE TO EXPERIENCE SOME SUBSIDENCE IN
THE WAKE OF SHORTWAVE WHICH WAS LIFTING NE ACROSS THE NORTH CAROLINA
WATERS AND THE OUTER BANKS NEAR MIDDAY.

HOWEVER...ANOTHER SHORTWAVE WAS EVIDENT ON WATER VAPOR IMAGERY
ACROSS THE TENNESSEE VALLEY. THIS MAY SERVE TO INCREASE THE LIFT
LATER THIS AFTERNOON AND TONIGHT AS THE SOUTHERN PERIPHERY OF THIS
FEATURE SKIRTS OUR FORECAST AREA.

INSTABILITY SHOULD BE ON THE INCREASE AS BREAKS IN THE CLOUD COVER
CONTINUE TO INCREASE WITH SLIGHTLY DRIER AIR WORKING INTO THE AREA.
STRONGER HEATING SHOULD YIELD MIXED LAYER CAPE VALUES AROUND 1500
J/KG MID AND LATE AFTERNOON. DIFFICULT TO DISCERN WHERE CONVECTION
MIGHT DEVELOP INITIALLY. MOST OF THE HIGH RESOLUTION MODELS HAVE NOT
INITIALIZED WELL. THE SEABREEZE MAY BECOME AN AREA OF INITIATION
THROUGH MID AFTERNOON WITH MORE INLAND AREAS FAVORED LATER IN THE
DAY. WILL CONFINE POPS TO SMALL CHANCE OR SLIGHT CHANCE THROUGH
TONIGHT.

HIGHS TODAY SHOULD BE WELL ABOVE THOSE OF MONDAY...LOWER TO MID 80S.
UPPER 80S ARE WITHIN REACH SHOULD CLOUDS DIMINISH FASTER THAN
CURRENTLY FORECAST. LOWS TONIGHT SHOULD BE COMMONLY IN THE UPPER 60S
TO NEAR 70 WITH A FEW MID 60S POSSIBLE INLAND.

&&

.SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/...
AS OF 300 AM TUESDAY...MID LEVEL TROUGHING WILL DOMINATE THE EASTERN
THIRD OF THE U.S WEDNESDAY THROUGH FRIDAY. AT THE
SURFACE...RESIDUAL LOW PRESSURE JUST TO THE SOUTH OF THE AREA WILL
KEEP THINGS UNSETTLED WEDNESDAY. LIFT WILL ALSO BE ENHANCED A
LITTLE BY THE MID LEVEL TROUGH. BY THURSDAY...HIGH PRESSURE TAKES
FIRM CONTROL AS IT BUILDS DOWN THE EAST COAST. THE GFS IS SHOWING
LIGHT QPF AND THIS MAY OCCUR IN THE FORM OF DRIZZLE OR LIGHT RAIN
SHOWERS AS THERE IS JUST ENOUGH ISENTROPIC LIFT...SPEED
CONVERGENCE TO WARRANT. WITH SOUNDINGS RELATIVELY DRY
HOWEVER...PRECIPITABLE WATER VALUES ARE ABOUT 1.25 INCHES...DO NOT
EXPECT ANYTHING SIGNIFICANT. TEMPERATURE GUIDANCE IS STABLE WITH
HIGHS IN THE 80S BOTH DAYS...A DEGREE OR TWO WARMER WEDNESDAY AND
OVERNIGHT LOWS...MODERATED BY THE WINDS AND EXPECTED BROKEN TO
OVERCAST SKIES IN THE LOWER TO MIDDLE 60S.

&&

.LONG TERM /FRIDAY THROUGH MONDAY/...
AS OF 300 AM TUESDAY...MEDIUM RANGE GUIDANCE REMAINS IN GOOD
AGREEMENT ON THE SCENARIO AT THE MID LEVELS THROUGH THE PERIOD. THE
MAIN BELT OF WESTERLIES SHOWS CONVERGENCE ALONG THE GREAT LAKES AND
UPPER MIDWEST REGIONS FOR FRIDAY AND SATURDAY. THE RESULT IS A
MASSIVE SURFACE HIGH THAT EXTENDS WELL DOWN INTO THE SOUTHEAST. THIS
PATTERN BREAKS DOWN SUNDAY AND MONDAY AS RIDGING DEVELOPS IN THE
FOUR CORNERS REGION WITH A DECENT MID LEVEL TROUGH MOVING THROUGH
THE OHIO VALLEY. THIS ALLOWS ANOTHER MOISTURE STARVED FRONT TO MOVE
ACROSS THE REGION MONDAY AND I HAVE MAINTAINED THE MENTION OF
SHOWERS AND THUNDERSTORMS. REGARDING POPS FOR FRIDAY INTO THE
WEEKEND...ONLY LIGHT SHOWERS AND OR DRIZZLE IS EXPECTED MAINLY
OFFSHORE. NO CHANGES TO THE TEMPERATURE FORECAST.

&&

.AVIATION /12Z TUESDAY THROUGH SATURDAY/...
AS OF 12Z...ANOTHER DAY WITH A WEAK GRADIENT...MAINLY LIGHT AND
VARIABLE WINDS EXPECTED. A COLD FRONT...REALLY THE SAME FRONT THAT
HAS BEEN HANGING AROUND FOR OVER A WEAK...WILL DROP IN TONIGHT.
THERE WILL BE CONVECTION OUT AHEAD OF IT...BUT RATHER LOW CONFIDENCE
ON THE AMOUNT OF COVERAGE WE WILL SEE TODAY. THINK MOST OF THE
CONVECTION WILL OCCUR THIS AFTERNOON...WITH A SMALL BATCH THIS
MORNING OVER SOUTHEAST NORTH CAROLINA. CEILINGS ARE GOING TO BOUNCE
AROUND THIS MORNING...IMPROVING TO VFR AT ALL TERMINALS BY LATE
MORNING. TONIGHT...FRONT PUSHES THROUGH THE REGION WITH WINDS
SHIFTING TO NORTHEAST...ALONG WITH POST FRONTAL STRATUS.

EXTENDED OUTLOOK...POST-FRONTAL MVFR CIGS MAY DEVELOP WED AS COOLER
AIR WEDGES INTO THE REGION. EARLY MORNING MVFR/IFR CIGS POSSIBLE ON
THU. GUSTY NORTHEAST WINDS EXPECTED FRI/SAT AS THE COOL AIR WEDGE
STRENGTHENS OVER THE CAROLINAS.

&&

.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 1100 AM TUESDAY...SWELL FROM DISTANT HURRICANE EDOUARD WILL
CONTINUE TO IMPACT THE WATERS AND WHILE WEAK TODAY...SWELL ENERGY IS
EXPECTED TO STRENGTHEN TONIGHT AND THROUGH MID WEEK. THIS WILL
ALLOW SEAS TO SLOWLY BUILD FROM...2 TO 3 FT TODAY AND UP TO 4 TO 5
FT LATE TONIGHT.

WINDS WILL BE LIGHT THROUGH THE PERIOD...10 KT OR LESS. THE
DIRECTION WILL BE ENE TO EASTERLY...BACKING TO NORTHEAST OVERNIGHT
IN THE WAKE OF A COLD FRONT AS HIGH PRESSURE TO OUR NORTH BEGINS TO
BECOME A LITTLE MORE ASSERTIVE.

SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/...
AS OF 300 AM TUESDAY...GENERALLY A NORTHEASTERLY COMPONENT TO THE
WINDS WILL PREVAIL WEDNESDAY. THE WINDS WILL BE LIGHT...TEN KNOTS
OR LESS AND THERE MAY BE A LITTLE VEERING DUE TO SEA BREEZE
EFFECTS. THE NORTHEAST FLOW WILL INCREASE IN MAGNITUDE A BIT
THURSDAY WITH A RANGE OF 10-15 KNOTS. SEAS WILL BE 2-4 FEET WITH
AN INCREASE TO 3-5 FEET BY FRIDAY MORNING.

LONG TERM /FRIDAY THROUGH SATURDAY/...
AS OF 300 AM TUESDAY...THE STRONG NORTHEASTERLY FLOW WILL CONTINUE
FRIDAY WITH WIND SPEEDS OF 15-20 KNOTS. SIGNIFICANT SEAS WILL BE
REPRESENTATIVE OF THE STRONG WIND FIELDS WITH 3-7 FEET AND LIKELY
SMALL CRAFT ADVISORIES. FOR SATURDAY THE WINDS DIMINISH TO 10-15
KNOTS. SEAS HOWEVER REMAIN ELEVATED AS A SIGNIFICANT SWELL COMPONENT
IS ADDED TO THE SPECTRUM.

&&

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

&&

$$

NEAR TERM...RJD
SHORT TERM...SHK
LONG TERM...SHK
AVIATION...43




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