Area Forecast Discussion
Issued by NWS Wilmington, NC

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000
FXUS62 KILM 212330
AFDILM

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE WILMINGTON NC
730 PM EDT SUN SEP 21 2014

.SYNOPSIS...
A COLD FRONT WILL CROSS THE AREA MONDAY WITH ISOLATED SHOWERS
AND THUNDERSTORMS. COOLER AIR WILL FOLLOW INTO MID WEEK. AN
UPPER TROUGH WILL DEEPEN OFFSHORE AND MOVE TOWARD THE COAST
LATE WEEK...BRINGING AN INCREASING CHANCE OF RAIN.

&&

.NEAR TERM /UNTIL 6 AM MONDAY MORNING/...
AS OF 720 PM SUNDAY...CLEAR SKIES SETTLING OVER SE NC AND NE SC.
CLOUDS MAY DEBUT VERY LATE INTO EARLY MONDAY AS A COLD FRONT
APPROACHES...AND AS A RESULT OVERNIGHT TEMPERATURES WILL REMAIN
SLIGHTLY ELEVATED COMPARED TO RECENT DAYS IN PRE-FRONTAL FLOW. NO
MENTIONABLE POP VALUES AT THIS TIME SINCE LOWER LEVELS WILL REMAIN
SOMEWHAT DRY DUE TO DOWNSLOPE WEST WIND TRAJECTORIES OFF THE
SURFACE. WILL AWAIT 00Z MODEL SUITES TO ASCERTAIN IF WE MAY NEED
A VERY SLIGHT CHANCE FOR OUR DEEPEST INTERIOR ZONES WEST OF I-95.
OTHERWISE A PLEASANT EVENING ON TAP WITH MILD TEMPERATURES AND
STARS THIS EVENING...CLOUD ENCROACHMENT LATE.

&&

.SHORT TERM /6 AM MONDAY MORNING THROUGH TUESDAY NIGHT/...
AS OF 300 PM SUNDAY...LONGWAVE UPPER PATTERN TO REMAIN
UNESTABLISHED THIS PERIOD...AS PROGRESSIVE FLOW ALOFT AND AT THE
SFC TO DOMINATE. MODELS INDICATE AN AMPLIFIED UPPER TROF TO
TEMPORARILY AFFECT THE EAST COAST MONDAY INTO TUESDAY...FOLLOWED
BY A TRANSITION TO UPPER RIDGING LATE IN THE SHORT TERM PERIOD.

AT THE SFC...MODELS AGREE TO HAVE A COLD FRONTAL PASSAGE EARLY
MONDAY WITH MAINLY CLOUDS ASSOCIATED WITH IT. HAVE INDICATED A LOW
POP DURING ITS PASSAGE AND POSSIBLY A LOW CHANCE POP DURING THE
IMMEDIATE POST COLD FRONTAL PASSAGE INTO TUE MORNING. STRONG 1035+
MB SFC HIGH CENTERED OVER THE NE STATES WILL RIDGE DOWN THE EAST
COAST AND ACROSS THE FA FOR THE REMAINDER OF THE SHORT TERM.
STRONG POST-COLD FRONTAL CAA NE FLOW WILL DOMINATE TUESDAY INTO
TUESDAY NIGHT. AS FOR TEMPS...WILL LEAN TOWARD THE COOLER GFS MOS
GUIDANCE WITH AROUND 80 FOR MONDAY MAX...MID-UPPER 70S FOR TUE
MAXES. THE MIN TEMP FORECAST HAS A POTENTIAL BUST WITH GFS AND NAM
MOS GUIDANCE NEARLY 1 TO 2 CATEGORIES DIFFERENT FROM ONE ANOTHER.
FOR NOW WILL TAKE THE EASY WAY OUT AND SELECT A HALFWAY POINT
BETWEEN THE 2. NEVERTHELESS...THE FA COULD SEE WIDESPREAD 50S FOR
LOWS ESPECIALLY TUE NIGHT.

&&

.LONG TERM /WEDNESDAY THROUGH SUNDAY/...
AS OF 300 PM SUNDAY...FIRST SEVERAL DAYS OF THE LONG TERM TO FEATURE
ON ONSHORE FLOW AS A LARGE AREA OF HIGH PRESSURE SITS WELL TO OUR
NORTH. MOISTURE FLUX WILL INCREASE RAIN CHANCES MAINLY ALONG THE
COAST WHILE FAIRLY WIDESPREAD CLOUD COVER TEMPERS AFTERNOON HIGHS
AND KEEPS THEM IN THE 70S. UPPER RIDGE BUILDS ACROSS THE GREAT LAKES
EMPHATICALLY ON FRIDAY THEN MOVING EAST-SOUTHEAST INTO SATURDAY.
THIS COULD LOWER RAIN CHANCES ON SATURDAY AS MID LEVELS DRY.
MOISTURE LOOKS TO DEEPEN ONCE AGAIN TO SUPPORT RAINFALL CHANCES ON
SUNDAY AS THIS FEATURE MOVES A BIT FURTHER TO THE EAST AND A DEEP
EASTERLY FLOW COMPONENT INTO THE CAROLINAS RETURNS.

&&

.AVIATION /00Z MONDAY THROUGH FRIDAY/...
AS OF 00Z...HIGH CONFIDENCE OF VFR THIS EVENING AND OVERNIGHT AS SW
WINDS REMAIN ELEVATED AHEAD OF AN APPROACHING COLD FRONT. CLOUDS
WILL INCREASE BUT SHOULD REMAIN AT OR ABOVE 4K. WINDS WILL SHIFT TO
THE NW 06-07Z AT KFLO/KLBT AND 09-10Z AT THE COASTAL TERMINALS.
ISOLATED LIGHT SHOWERS POSSIBLE WITH FROPA THUS WILL INCLUDE VCSH.
SHOWERS SHOULD DISSIPATE DURING THE MORNING HOURS AS VFR CONTINUES.

THICKNESS PATTERNS SUGGEST ACTUAL COLD AIR WILL LAG QUITE AWAYS
BEHIND THE FRONT. A SLUGGISH PRESSURE PATTERN MAY CAUSE WIND
DIRECTIONS TO BECOME VARIABLE AT THE COASTAL TERMINALS BY LATE
MORNING. WEAK LOW LEVEL CONVERGENCE AT THE COASTAL TERMINALS ALONG
WITH INCREASING PVA MAY CAUSE MORE SIGNIFICANT SHOWER DEVELOPMENT IN
THE AFTERNOON. STILL APPEARS VFR WILL CONTINUE AT THE COASTAL
TERMINALS IN THE AFTERNOON.

EXTENDED OUTLOOK...VFR THROUGH WEDNESDAY. RAIN DEVELOPING THURSDAY
AFTERNOON INTO FRIDAY WITH POSSIBLE MVFR/IFR CONDITIONS.

&&

.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 720 PM SUNDAY...WINDS BACKING TO THE SOUTHWEST AHEAD OF A
COLD FRONT MOVING IN FROM THE NORTHWEST AND INCREASING TO 15-20
KNOTS BY MORNING. SEAS WILL REMAIN IN A RATHER CONFINED RANGE OF
2-4 FEET...HIGHEST OFFSHORE. NO ADVISORIES OR CAUTION STATEMENTS
PLANNED.

SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/...
AS OF 300 PM SUNDAY...AT THE START OF THE SHORT TERM...THE LOCAL
WATERS WILL BE SUBJECT TO A COLD FRONTAL PASSAGE. FOLLOWED BY
STRONG RIDGING FROM THE 1035+ MB HIGH CENTERED OVER THE NE STATES.
LOOKING AT TIGHTENED SFC PG COMBINED WITH CAA SURGE FOR LATE
MONDAY THRU TUESDAY. THIS WILL LIKELY REQUIRE A SCA...OR AT LEAST
A SCEC...FOR MUCH OF THE SECOND HALF OF SHORT TERM. POST COLD-
FRONTAL WIND SPEEDS TO RANGE BETWEEN 15 TO 25 KT. SIGNIFICANT
SEAS WILL BE DOMINATED BY WIND DRIVEN SHORT PERIOD WIND
WAVES...AND COULD CLIMB TO 3 TO 7 FT DEPENDENT ON THE COASTLINE
AND COASTAL WATERS CONFIGURATION. IE. SIG. SEAS TO APPROACH 6 TO 7
FT ACROSS THE OUTER WATERS OFF CAPE FEAR DURING SECOND HALF OF
THE SHORT TERM PERIOD.

LONG TERM /WEDNESDAY THROUGH FRIDAY/...
AS OF 3 PM SUNDAY...NASTY NORTHEASTERLY GRADIENT IN PLACE FOR THE
ENTIRE PERIOD DUE TO QUASI STATIONARY LARGE AREA OF HIGH PRESSURE
ACROSS THE NERN U.S. WINDS AND SEAS BOTH EXPECTED TO MEET SMALL
CRAFT ADVISORY THRESHOLDS FOR THE ENTIRE LONG TERM PERIOD...SAVE
FOR PERHAPS WINDS BEING JUST A TAD SHY ON WEDNESDAY.

&&

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

&&

$$

NEAR TERM...MJC
SHORT TERM...DCH
LONG TERM...MBB
AVIATION...MRR
MARINE...SHK/DCH/MBB



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