Area Forecast Discussion
Issued by NWS Wilmington, NC

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000
FXUS62 KILM 150835
AFDILM

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE WILMINGTON NC
435 AM EDT MON SEP 15 2014

.SYNOPSIS...
A FRONT STALLED ACROSS SOUTHERN GEORGIA WILL RETURN NORTH
TODAY...ONLY TO BE PUSHED SOUTH AGAIN TUESDAY AS HIGH PRESSURE BUILDS
EASTWARD ACROSS THE PLAINS STATES. THIS HIGH WILL MOVE ACROSS THE
MID-ATLANTIC STATES LATE IN THE WEEK...PROVIDING FALL- LIKE
WEATHER WEDNESDAY THROUGH SUNDAY.

&&

.NEAR TERM /THROUGH TONIGHT/...
AS OF 330 AM MONDAY...THE FA MAINLY UNDER A LONGWAVE LOW AMPLITUDE
UPPER TROF. THIS FLATTENED UPPER TROF HAS PREVENTED THE SFC COLD
FRONT FROM PROGRESSING TOO FAR SOUTH DURING THE PAST COUPLE DAYS.

AS FOR PCPN THIS MORNING...WEAK ISENTROPIC LIFT NORTH OF THE
MEANDERING FRONTAL BOUNDARY JUST SOUTH OF THE FA...WILL INITIALLY BE
THE DRIVING FORCE FOR LIGHT RAIN SHOWERS OR DRIZZLE...ESPECIALLY
ACROSS THE ILM SC COUNTIES THIS MORNING. THE FRONTAL BOUNDARY WILL
REVERSE COURSE TODAY AND LIFT BACK SLOWLY TO THE NORTH...WHILE AT
THE SAME TIME SLOWLY DISSIPATING. FOR THIS AFTERNOON...INSOLATION
WILL HELP WITH SOME INCREASING INSTABILITY. LIFT...ALBEIT
WEAK...FROM THE LIFTING FRONT...WILL AID IN THE DEVELOPMENT
OF THUNDERSTORMS. LOW-MEDIUM CHANCE FOR PCPN THIS AFTN INTO THIS
EVENG. FOR TONIGHT...WEAK SFC TROF/COLD FRONT TO APPROACH FROM THE
WEST BY TUE DAYBREAK. MODELS SOMEWHAT NOISY WITH DYNAMICS ALOFT
IE. EMBEDDED S/W TROF OR VORT...IN THAT WILL HOLD ONTO THE CHANCE
FOR PCPN AND NOT GO ANY HIER AT THE MOMENT. AS FOR TEMPS...HAVE
COMPROMISED BETWEEN THE NAM AND GFS MOS GUIDANCE FOR BOTH MAX/MIN
FCST. WITH ANY BREAKS IN THE CLOUDINESS...THE WARMER GFS MAY BE
THE WAY TO GO FOR MAXES TODAY.

&&

.SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/...
AS OF 3 AM MONDAY...MID LEVEL RIDGING WILL SHARPEN AND MOVE ACROSS THE
WEST COAST AS TROUGHING DEVELOPS ACROSS THE EASTERN THIRD OF THE
U.S. THIS TROUGH WILL EVENTUALLY PUSH A COLD FRONT THROUGH THE AREA
LATE TUESDAY INTO EARLY WEDNESDAY. WILL MAINTAIN A GOOD CHANCE OF
SHOWERS AND THUNDERSTORMS FOR TUESDAY AS THE LINGERING MOISTURE
WARRANTS AHEAD OF THE FRONT. MORE OF A SHOWERY SCENARIO FOR
WEDNESDAY ESPECIALLY ACROSS NORTH CAROLINA. STILL ENOUGH INSTABILITY
TO WARRANT SLIGHT CHANCE OF THUNDER NORTH WITH THUNDERSTORMS THE
PRIMARY MODE FOR SOUTH CAROLINA. TEMPERATURES STILL ON THE WARM SIDE
FOR TUESDAY IN THE MIDDLE 80S DROPPING A GOOD FIVE TO TEN DEGREES
WEDNESDAY. OVERNIGHT LOWS WILL BE IN THE 60S.

&&

.LONG TERM /THURSDAY THROUGH SUNDAY/...
AS OF 3 AM MONDAY...THE EXTENDED FORECAST CONTINUES TO SHOW A MOSTLY
ZONAL MID LEVEL PATTERN INITIALLY WITH MORE AMPLITUDE DEVELOPING
LATE. THE WESTERLIES WILL SHOW CONFLUENCE ACROSS THE CENTRAL
PLAINS/GREAT LAKES WHICH WILL ALLOW A RATHER EXPANSIVE AREA OF
SURFACE HIGH PRESSURE TO BUILD DOWN THE EAST COAST. THIS WILL
MAINTAIN A SOMEWHAT DRY AND COOL FLOW ACROSS OUR FORECAST AREA.
THE HIGH WEAKENS AS MID LEVEL SUPPORT WANES AND HIGH PRESSURE
BUILDS ACROSS THE WESTERN U.S. AT THE MID LEVELS. THIS WILL SET
THE STAGE FOR ANOTHER SYSTEM TO AFFECT THE AREA LATE OR JUST
BEYOND THIS FORECAST PERIOD. TEMPERATURES WILL BE JUST A LITTLE
BELOW CLIMATOLOGY MODERATING EVER SO SLIGHTLY LATE IN THE PERIOD.
THE ONLY POPS ARE RELEGATED TO JUST OFFSHORE WHERE JUST ENOUGH
MOISTURE WARRANTS.

&&

.AVIATION /09Z MONDAY THROUGH FRIDAY/...
AS OF 06Z...MVFR CIGS 1-2KFT WILL PREVAIL OVERNIGHT WITH THE ILM
SC TERMINALS POSSIBLY OBSERVING CIGS LESS THAN 1K FT IN A 3-5 HR
WINDOW SURROUNDING DAYBREAK MON DUE TO THEIR CLOSER PROXIMITY TO
THE STALLED COLD FRONT SOUTH OF THE AREA. CANNOT RULE OUT TEMPO
IFR CIGS AT KILM AND ESPECIALLY KLBT...AND MAY INCLUDE A SUB 2K
FOOT CEILING AT LBT AT PRESS TIME. FOG DOES NOT SEEM LIKE A BIG
CONCERN GIVEN THE PERSISTENT NORTHEAST FLOW AND EXTENSIVE CLOUD
COVER...BUT WE COULD SEE SOME MVFR VSBYS INLAND. GUIDANCE SUGGESTS
FOG MAY BECOME A PLAYER TOWARD DAYBREAK ACROSS THE INLAND
TERMINALS...DROPPING VSBYS BELOW 1SM. FOR NOW WILL KEEP THE LOW
STRATUS DECK AS THE MAJOR PLAYER FOR ANY IFR CONDITIONS. LIGHT
NORTH TO NORTHEAST WINDS AT THE START WILL VEER TO THE EAST AND
SOUTHEAST LATER IN THE DAY. HAVE ADDED VCSH FOR THE SOUTHERN
TERMS AFTER 20Z AS THE WASHED OUT BOUNDARY LIFTS BACK NORTHWARD
ACROSS OUR CWA.

EXTENDED OUTLOOK...CHANCE OF SHOWERS/TEMPO MVFR TUE AHEAD OF A COLD
FRONT. POST-FRONTAL MVFR CIGS MAY DEVELOP WED AS COOLER AIR WEDGES
INTO THE REGION. OTHERWISE EXPECT VFR THROUGH FRI.

&&

.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 400 AM MONDAY...MODEL SFC PRESSURE PATTERN AND WEAK GRADIENT
SUPPORT A WEAK WEDGE THIS MORNING THAT WEAKENS AND GIVES WAY TO
THE APPROACHING FRONTAL BOUNDARY FROM THE SOUTH. LOOKING AT A SLOW
VEERING TREND IN THE WIND FIELD...FROM NE THIS MORNING TO EAST
MIDDAY...AND SOUTHEAST THIS AFTERNOON AND EARLY EVENING. FOR
TONIGHT VARIABLE WINDS INITIALLY WILL BECOME WESTERLY AS A COLD
FRONT APPROACHES FROM THE WEST TOWARD DAYBREAK TUE. WIND SPEEDS
INITIALLY 10 TO 15 KT DUE TO THE WEDGE...WILL DROP BACK TO AROUND
10 KT AS THE SFC PG WEAKENS. SIGNIFICANT SEAS WILL RUN 2 TO 3 FT
WITH AN AVERAGE PERIOD OF 4 TO 5 SECONDS.

SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/...
AS OF 3 AM MONDAY...LIGHT WIND FIELDS WILL PREVAIL OVER THE WATERS
FOR MOST OF TUESDAY. IF ANYTHING...WINDS WILL HAVE A NORTHERLY
COMPONENT OF TEN KNOTS OR LESS. THE WINDS ACQUIRE MORE DEFINITION BY
WEDNESDAY MORNING AS A FRONT MOVES SLOWLY TO THE SOUTH. EXPECT AN
INCREASING NORTHEASTERLY FLOW OF 10-15 KNOTS. SIGNIFICANT SEAS
INCREASE FROM 2-3 FEET TO 3-5 FEET AND POSSIBLY SOME SIX FOOTERS
ACROSS THE OUTER WATERS WEDNESDAY.

LONG TERM /THURSDAY THROUGH FRIDAY/...
AS OF 3 AM MONDAY...ESSENTIALLY A NORTHEAST FLOW THROUGH THE PERIOD.
THE STRONGEST WINDS WILL OCCUR LATE AS HIGH PRESSURE...ANCHORED
ACROSS THE NORTHEAST STRENGTHENS. SPEEDS WILL BE IN A 15-20 KNOT
RANGE CLOSER TO AND POSSIBLY JUST EXCEEDING THE HIGHER END BY FRIDAY
MORNING. SEAS WILL HOVER AT OR JUST BELOW SMALL CRAFT CRITERIA...3-5
FEET.

&&

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

&&

$$
SYNOPSIS...SHK
NEAR TERM...DCH
SHORT TERM...SHK
LONG TERM...SHK
AVIATION...DCH/BJR




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