Area Forecast Discussion
Issued by NWS Wilmington, NC

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000
FXUS62 KILM 160728
AFDILM

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

.SYNOPSIS...
A COLD FRONT WILL PUSH OFFSHORE WEDNESDAY MORNING. HIGH PRESSURE
WILL RIDGE 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 3 AM TUESDAY...AT THE UPPER LEVELS A FLATTISH LONG WAVE
TROUGH WILL DEEPEN THROUGH THE NEAR TERM AS A SERIES OF WEAK
DISTURBANCES TRANSIT OVERHEAD. THE STRONGEST DISTURBANCE WILL MOVE
THROUGH THIS MORNING. AT THE SURFACE A RATHER WEAK AND AMORPHOUS
PRESSURE PATTERN MAKES IT DIFFICULT TO DISCERN EXACT FRONTAL
PLACEMENT AND THUS SUBSEQUENT FRONTAL MOTION BUT THE GENERAL
SCENARIO IS FAIRLY CLEAR. A NEARLY STATIONARY FRONT ACROSS THE DEEP
SOUTH SEEMS TO BE IN THE PROCESS OF DISSIPATING WHILE LIFTING BACK
NORTH AS A COLD FRONT APPROACHES FROM THE NORTHWEST. A CONSENSUS OF
GUIDANCE MERGES THE FRONTS TODAY OVER THE EASTERN SEABOARD...KEEPING
A BROAD AND WEAK PRESSURE GRADIENT IN PLACE THROUGH THE DAYLIGHT
HOURS WITH LITTLE IN THE WAY OF SIGNIFICANT ISENTROPIC LIFT. POST
FROPA HIGH PRESSURE BUILDS IN MORE ASSERTIVELY OVERNIGHT ALTHOUGH
COLD ADVECTION WILL TRAIL WELL BEHIND THIS FEATURE.

NOT OVERLY IMPRESSED WITH PRECIPITATION CHANCES TODAY. MODEL
SOUNDINGS SHOW A MARGINALLY TO MODERATELY UNSTABLE AIRMASS TODAY AND
CONVECTIVE INDICES SHOW ISOLATED TO SCATTERED CONVECTION IS A
POSSIBILITY...BUT MOISTURE PROFILES SHOW MID LEVELS ARE ON THE DRY
SIDE AND AFOREMENTIONED LIFT ASSOCIATED WITH FROPA NOT VERY STRONG.
BEST SHOT AT SUBSTANTIAL CONVECTION LOOKS TO BE THIS MORNING AS AN
UPPER DISTURBANCE SKIRTS THE SOUTHERN PORTION OF OUR CWA. WILL BE
KEEPING POPS IN THE FAIRLY MODEST 20 TO 30 PERCENT RANGE FOR
TODAY...WITH CHANCES TRAILING OFF AFTER MIDNIGHT AS DRYER AND MORE
STABLE AIR FILTERS IN POST-FROPA.

TEMPERATURES WILL BE QUITE SEASONAL...WITH MODEL CONSENSUS GIVING
US HIGHS IN THE MID 80S AND LOWS IN THE MID TO UPPER 60S.

&&

.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 /07Z TUESDAY THROUGH SATURDAY/...
AS OF 06Z...EXPECT OVERNIGHT MVFR/IFR CIGS TO FILL IN ONCE AGAIN AS
COOL MOIST AIR REMAINS IN PLACE OVER OUR AREA. HIGHEST CONFIDENCE
FOR IFR CIGS IS INLAND AT KFLO/KLBT AFTER 09Z. ALONG THE COAST...
1-2KFT CIGS ARE EXPECTED TO PREVAIL...THOUGH A BRIEF PERIOD OF IFR
BY DAYBREAK CANNOT BE RULED OUT AT KCRE/KMYR. HAVE ALSO INCLUDED
VCSH FOR THE SOUTHERN TERMS THIS MORNING AS DEEPER MOISTURE
INCREASES WITH A REMNANT FRONT LIFTING NORTHWARD AND AN UPPER
DISTURBANCE MOVING OVERHEAD. MVFR CIGS MAY PERSIST THROUGH MUCH OF
THE MORNING...BUT VFR CONDITIONS SHOULD EMERGE DURING THE AFTN HOURS
AS LIGHT NORTH WINDS BECOME SOUTHEAST AOB 10 KT. A COLD FRONT WILL
NEAR OUR NORTHERN TERMINALS NEAR THE END OF THE TAF PERIOD AS HIGH
PRESSURE EXPANDS SOUTHWARD. BUT ATTM...IT APPEARS THE WIND SHIFT
WILL HOLD OFF UNTIL AFTER THE VALID PERIOD.

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 3 AM TUESDAY...A WEAK PRESSURE PATTERN WILL PREVAIL THROUGH
THE NEAR TERM PERIOD. WINDS TODAY AND TONIGHT WILL STAY GENERALLY
UNDER 10 KTS...WITH SEAS NOT STRAYING FAR FROM THEIR PRESENT 2 TO 3
FT RANGE.

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.

&&

$$
SYNOPSIS...SHK
NEAR TERM...REK
SHORT TERM...SHK
LONG TERM...SHK
AVIATION...BJR







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