Area Forecast Discussion
Issued by NWS Wilmington, NC

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000
FXUS62 KILM 021036
AFDILM

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE WILMINGTON NC
636 AM EDT SUN AUG 2 2015

.SYNOPSIS...
STATIONARY FRONT WILL REMAIN ACROSS THE AREA TODAY PRODUCING
ISOLATED SHOWERS AND THUNDERSTORMS NEAR THE COAST. A WEAK WAVE OF
LOW PRESSURE WILL MOVE ALONG THIS FRONT LATE TONIGHT AND ON
MONDAY...BRINGING SLIGHTLY BETTER RAIN CHANCES TO THE AREA. THIS
FRONT WILL DISSIPATE ON MONDAY AS BERMUDA HIGH RIDGES BACK INTO
THE AREA THROUGH LATE WEEK. TEMPERATURES WILL REMAIN SEASONABLE
TO SLIGHTLY ABOVE NORMAL THROUGH THE WEEK. A COLD FRONT WILL
APPROACH NEXT WEEKEND.

&&

.NEAR TERM /THROUGH TONIGHT/...
AS OF 600 AM SUNDAY...PATCHY FOG WAS AROUND...OTHERWISE IT WAS A
CLEAR TO PARTLY CLOUDY SUNRISE.

TODAY IS EXPECTED TO BE SIMILAR TO SAT IN MANY RESPECTS. A WEAK
FRONT/LAND BREEZE WILL BE OFFSHORE EARLY THIS MORNING AND THEN
WITH STRONG HEATING...A DEVELOPING SEABREEZE WILL PUSH INLAND. THE
FORECAST AREA ON THE WHOLE WILL BE DRIER TODAY THAN ON SAT.
PRECIPITABLE WATER VALUES WILL BE AN INCH AND A HALF OR LESS
THROUGHOUT DURING THE TIME OF PEAK HEATING. MODEL SOUNDINGS ARE
ALSO SHOWING A CAP OF WARMER TEMPS ALOFT AT AROUND 12 KFT. THESE
CONDITIONS SHOULD KEEP ANY CONVECTION ISOLATED...EVEN ALONG THE
SEABREEZE. WILL CARRY SLIGHT CHANCE/SMALL CHANCE ALONG THE SEABREEZE
AS IT MOVES INLAND...MAINLY THIS AFTERNOON AND EVE. WILL KEEP A
DRY FORECAST ALONG THE INTERSTATE 95 CORRIDOR AND POINTS WEST.

SINCE FORECAST HIGHS OVER THE LAST COUPLE OF DAYS HAVE BEEN TOO
LOW...WILL GO AGAINST THE GRAIN...DESPITE THE UPPER TROUGH AND
LOWERING HEIGHTS. WILL FORECAST MAINLY MID 90S...ALTHOUGH A FEW
SPOTS WELL INLAND MAY AGAIN REACH THE UPPER 90S. ALONG THE COAST...
LOWER 90S WILL BE MOST COMMON ALTHOUGH THE BEACHES MAY BY STYMIED
IN THE UPPER 80S GIVEN THE DEVELOPING ONSHORE FLOW.

TONIGHT...THE FORECAST BECOMES MORE COMPLICATED. THE NAM MODEL IS
FORECASTING A CLOSED CIRCULATION DEVELOPING ALONG A WEAK BOUNDARY.
THE NAM DEVELOPS THE LOW TO OUR S AND CARRIES IT N ALONG THE COAST
OF NORTHEAST SOUTH CAROLINA AND SOUTHEAST NORTH CAROLINA DURING THE
PRE-DAWN HOURS OF MON AND MON MORNING. THE LOW THEN LIFTS N OF CAPE
LOOKOUT MON AFTERNOON. THIS RECENT DEVELOPMENT DOES NOT SEEM A
LIKELY SCENARIO. THE GFS SHOWS MORE OF AN INVERTED TROUGH POKING UP
THE COAST. HOWEVER...THESE SOLUTIONS GIVE A SIMILAR FORECAST AS IT
RELATES TO SENSIBLE WEATHER WITH PRECIPITABLE WATER VALUES RAMPING
HIGHER VERY LATE TONIGHT ALONG THE COAST. THUS WILL SHOW POPS
INCREASING DURING THE OVERNIGHT HOURS AND INTO MON MORNING. AS IS
OFTEN THE CASE...THE MODELS DO SEEM TO BE TOO FAR WEST WITH THEIR
DEVELOPING PRECIPITATION SHIELD...ALTHOUGH I DO AGREE THERE WILL BE
A RATHER SHARP POP GRADIENT. WILL CONFINE LIKELY POPS TO THE
WATERS...TRENDING TO GOOD CHANCE/CHANCE ALONG THE COAST WITH SMALL
POPS DECREASING BELOW THRESHOLD AS YOU MOVE TO THE I-95 CORRIDOR.

&&

.SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/...
AS OF 300 AM SUNDAY...PERSISTENT STATIONARY FRONT WILL FINALLY
DISSIPATE OVERHEAD MONDAY THANKS TO RIDGING SLOWLY BULGING OUT OF
THE ARKLATEX REGION. THIS LEADS TO A MORE TYPICAL MID-LEVEL PATTERN
FOR AUGUST WITH VERY WEAK BAROCLINIC GRADIENTS...ERODING THE
BOUNDARY COMPLETELY.

BEFORE THIS OCCURS THOUGH...ENOUGH FORCING WILL PERSIST ALONG THE
FRONT AND AN AFTN SEA BREEZE BOUNDARY TO PRODUCE ISOLATED/SCT
SHOWERS AND TSTMS MONDAY. THE BEST CHANCE WILL BE ACROSS THE EASTERN
THIRD OF THE CWA WHERE PWATS WILL BE MUCH HIGHER SE OF THE
FRONT...AND WHERE THE SEA BREEZE WILL LIKELY AID IN CONVECTIVE
DEVELOPMENT. ADDITIONALLY...GUIDANCE IS INDICATING A WAVE OF LOW
PRESSURE DEVELOPING ALONG THIS BOUNDARY AND ENHANCING PRECIP ALONG
THE CAPE FEAR COAST. WHILE THE NAM APPEARS TOO STRONG WITH THIS
FEATURE...HAVE SEEN A FEW WAVES ALONG THIS FRONT OVER THE PAST FEW
DAYS...AND THUS THERE IS SOME CONFIDENCE IN ONE MORE THIS PERIOD.
HAVE BUMPED POP TO LOW-LIKELY FROM ABOUT HOLDEN BEACH TO CAROLINA
BEACH AND SE...WITH HIGH CHC JUST INLAND FROM THERE. THERE WILL
BE A VERY SHARP GRADIENT HOWEVER...AND THE BEST CONVECTION MAY
REMAIN LURKING JUST OFFSHORE.

THE WESTERN HALF OF THE CWA SHOULD AGAIN BE TOO DRY AS A VERY SHARP
MOISTURE GRADIENT EXISTS ACROSS THE AREA...AND WILL KEEP POP SILENT
FOR THE I-95 COUNTIES. TEMPS ON MONDAY WILL BE SIMILAR TO WHAT WE
HAVE SEEN THE PAST SEVERAL DAYS...ABOUT 90 AT THE COAST...RISING
TO AROUND 97 IN THE WARMEST INLAND ZONES. MINS WILL REMAIN ABOVE
CLIMO ACROSS THE AREA...72 WELL INLAND TO AS WARM AS 78 ON THE
BEACHES.

TUESDAY WILL BE THE NICER OF THE TWO DAYS...BUT ALSO HOTTER THANKS
TO HEIGHTS BUILDING ALOFT AS THE RIDGE DISPLACES THE LONGWAVE
TROUGH. 850MB TEMPS CLIMB TO AROUND 20C...AND PWATS DROP BELOW 1.5
INCHES BENEATH A STRENGTHENING SUBSIDENCE INVERSION. 6-HR SREF PROBS
FOR 0.01 INCHES DEPICT A SMALL AREA OF 40-50% ALONG THE SEA BREEZE
TUESDAY...BUT THIS IS WELL BELOW THE PERSONAL THRESHOLDS OF 80%+ FOR
THIS PARAMETER FOR PRECIP. THIS COMBINED WITH VERY DRY AIR ABOVE THE
INVERSION AND VERY WEAK INSTABILITY SHOULD PREVENT ANY SHOWER
ACTIVITY...AND WILL KEEP POP SILENT ON TUESDAY. TEMPS WILL BE QUITE
WARM TUESDAY...WITH SOME DOWNSLOPE FLOW DRIVING HIGHS INTO THE MID
90S ACROSS MUCH OF THE AREA...UPR 90S IN THE WARM SPOTS...WITH LOWS
TUESDAY NIGHT FALLING ONLY INTO THE MID AND UPR 70S.

&&

.LONG TERM /WEDNESDAY THROUGH SATURDAY/...
AS OF 300 AM SUNDAY...HOT WEATHER ON TAP FOR MUCH OF THE EXTENDED
AS LARGE UPPER RIDGE EXPANDS ACROSS THE SOUTHERN TIER AND INTO THE
MID- ATLANTIC. THICKNESSES LOCALLY DO NOT GET EXCEEDINGLY
ROBUST...BUT WILL BE ABOVE CLIMO...AND COMBINE WITH WARM 850MB
TEMPS TO KEEP HIGHS AND LOWS LIKELY 3-6 DEGREES ABOVE CLIMO WED
THU AND FRI. WED AND THU ALSO LOOK TO BE PRETTY DRY ACROSS THE
AREA AS THE MID-LEVELS ARE DRY AND NO SIGNIFICANT FORCING IS
EXPECTED. HOWEVER...WILL MAINTAIN INHERITED SCHC WED FOR TYPICAL
SUMMERTIME ACTIVITY...AND DROP POP FROM INHERITED FOR THURSDAY FOR
THE SAME REASONS. BY FRIDAY...A BOUNDARY WILL BEGIN TO APPROACH
AND MOISTURE WILL INCREASE SO CONVECTION CHANCES WILL BEGIN TO
RAMP UP...ESPECIALLY INTO SATURDAY AS THE FRONT CROSSES INTO THE
AREA. WILL KEEP POP IN THE CHC RANGE FOR D6/D7 WITH COOLER TEMPS
FOLLOWING THE FRONT NEXT WKND.

&&

.AVIATION /06Z SUNDAY THROUGH THURSDAY/...
AS OF 06Z...EARLIER CONVECTION HAS DISSIPATED ACROSS THE CWA AND
SKIES HAVE TRENDED CLEAR FOR THE MOST PART. WITH SUFFICIENT LOW-
LEVEL MOISTURE...AN INVERSION AND LIGHT WINDS...PATCHY FOG IS
FORECAST ACROSS THE INLAND TERMINALS WITH MVFR VSBY BETWEEN
09-12Z. MAIN WEATHER FEATURE FOR TODAY WILL BE THE STATIONARY
FRONT/SEA BREEZE WHICH WILL TRIGGER ISOLATED SHOWERS OR TSTMS
ACROSS THE COASTAL TERMINALS THIS AFTERNOON AND EVE. WILL KEEP VFR
AT ALL THE TERMINALS...BUT CANNOT RULE OUT BRIEF MVFR VSBY/
CEILING IF CONVECTION OCCURS DIRECTLY OVER KILM/KCRE/KMYR.

EXTENDED OUTLOOK...PREDOMINANTLY VFR THROUGH THE PERIOD WITH A
SLIGHT CHANCE AFTERNOON SHRA/TSRA.

&&

.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 600 AM SUNDAY...CONVECTION...WHILE WIDESPREAD...WAS ALL
BEYOND 40 NM OF THE COAST.

A WEAK FRONT WILL INTERACT WITH THE DAILY AFTERNOON SEA BREEZE
AND EARLY MORNING LAND BREEZE. A TROUGH WILL EXPAND NORTH ALONG
THE COAST TONIGHT. THE STRONGEST WINDS ARE AGAIN EXPECTED LATE IN
THE AFTERNOON AND THROUGH THE EVE...UP TO AROUND 15 KT. MORNING
WINDS WILL BE RATHER VARIABLE IN DIRECTION...BIASED TOWARD
OFFSHORE GIVEN THE POSITION OF THE LAND BREEZE AND LIGHT. THE WIND
DIRECTION THIS AFTERNOON AND TONIGHT WILL BE SOUTH. OVERNIGHT...
THE WINDS ARE NOT EXPECTED TO DROP OFF SIGNIFICANTLY GIVEN THE
EXPANDING TROUGH. SEAS WILL BE 3 TO 4 FT TODAY WITH SOME 5 FT SEAS
DEVELOPING ACROSS PORTIONS OF THE OUTERMOST WATERS TONIGHT. SEAS
WILL BE A FUNCTION OF BOTH WIND AND PERSISTENT SWELL. THERE WILL
BE TWO DISTINCT SWELL COMPONENTS...ONE FROM THE S ON THE ORDER OF
7 SECONDS AND ONE FROM THE SE ON THE ORDER OF 10-11 SECONDS.

SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/...
AS OF 300 AM SUNDAY...POSSIBLE SMALL CRAFT ADVISORY CONDITIONS
DEVELOPING MONDAY AS A WAVE OF LOW PRESSURE MOVES ALONG A
STATIONARY BOUNDARY WHICH WILL BE WAVERING ALONG THE COAST. AS
THIS WAVE MOVES ALONG THE FRONT...THE GRADIENT WILL
PINCH...CAUSING S/SW WINDS TO INCREASE ACROSS THE WATERS. HAVE
EASED WINDS A BIT BELOW GUIDANCE SINCE THE WAVE SHOULD BE
WEAK...BUT 15-20 KT WILL BECOME WIDESPREAD ON MONDAY. ALTHOUGH
THIS IS JUST BELOW SCA THRESHOLDS...THESE WINDS WILL CREATE A WIND
WAVE OF 5 FT AT 6 SEC...WHICH WILL COMBINE WITH A 2FT/11SEC SWELL
TO PRODUCE 4-6 FT SEAS MUCH OF MONDAY. THE FRONT WILL DISSIPATE
LATE MONDAY WITH A MUCH WEAKER GRADIENT LEFTOVER FOR TUESDAY.
BERMUDA HIGH PRESSURE REBUILDING TOWARDS THE WATERS WILL MAINTAIN
A SW WIND OF 10-15 KT...BUT SEAS WILL FALL TO 3-5 FT...HIGHEST
EARLY IN THE DAY.

LONG TERM /WEDNESDAY THROUGH THURSDAY/...
AS OF 300 AM SUNDAY...BERMUDA HIGH PRESSURE DOMINATES THE FLOW
WED AND THU AS A NORMAL SUMMERTIME PATTERN DEVELOPS. WINDS AROUND
THIS FEATURE WILL BE FROM THE TYPICAL SW DIRECTION...WITH SPEEDS
OF 10-15 KT THROUGH MUCH OF THE PERIOD. THESE WINDS WILL DRIVE A
WIND CHOP ATOP AN 11 SEC GROUND SWELL...AND SEAS WILL BE 3-4
FT...ISOLATED UP TO 5 FT AT TIMES...BOTH DAYS.

&&

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

&&

$$

NEAR TERM...RJD
SHORT TERM...JDW
LONG TERM...JDW
AVIATION...RJD/MAC


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