Area Forecast Discussion
Issued by NWS Wilmington, NC

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000
FXUS62 KILM 290728
AFDILM

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE WILMINGTON NC
325 AM EDT FRI MAY 29 2015

.SYNOPSIS...
SEASONABLE WEATHER WILL PREVAIL THROUGH EARLY NEXT WEEK AS WEAK
HIGH PRESSURE REMAINS OFFSHORE. DRY AIR ALOFT WILL LIMIT
PRECIPITATION WITH ONLY ISOLATED SHOWERS POSSIBLE THROUGH THE
WEEKEND. AN APPROACHING BUT WEAKENING COLD FRONT WILL BRING A
SLIGHTLY BETTER CHANCE OF SHOWERS AND A FEW THUNDERSTORMS EARLY
NEXT WEEK.

&&

.NEAR TERM /THROUGH TONIGHT/...
AS OF 300 AM FRIDAY...SURFACE HIGH PRESSURE CENTERED SIGNIFICANTLY
NE OF THE CAROLINAS IS IMPRESSIVELY MAINTAINING A RIDGE AXIS BACK
ACROSS THE SOUTHEAST UNITED STATES. AT THE SAME TIME...AMPLIFIED MID-
LEVEL RIDGING REMAINS IN PLACE ACROSS THE EASTERN CONUS...WITH THAT
RIDGE CENTER JUST NORTH OF THE AREA. THESE FEATURES TOGETHER CREATE
CONTINUED WARM TEMPERATURES WITH ONLY MINIMAL PRECIP CHANCES.

WITH THE HIGH PRESSURE CENTER WELL NE OF THE AREA...LONG RETURN FLOW
IS MORE E THAN SE INTO THE CAROLINAS. THIS IS IMPORTANT BECAUSE IT
PROVIDES LONG RESIDENCE TIME FOR PARCELS OVER THE ATLANTIC TO ADVECT
MOISTURE ONSHORE. HOWEVER...BACK TRAJECTORIES SHOW THAT THE AIR
MOVING ONSHORE IS ACTUALLY MODIFIED CONTINENTAL AIR FROM
CANADA...WHICH HAVE TRAVERSED ALL THE WAY AROUND THE HIGH BEFORE
RETURNING TO THE US COAST. THIS MEANS THAT TOTAL MOISTURE IS LESS
THAN WOULD TYPICALLY BE EXPERIENCED WITH THIS SETUP...AND THESE
DRIER PARCELS COMBINED WITH SUBSIDENCE FROM THE RIDGING ALOFT WILL
CAP MUCH CONVECTION TODAY. STILL...HIGH RES GUIDANCE AGREES IN
DEVELOPING SHOWER ACTIVITY MOVING INLAND TODAY WITH THE
RESULTANT...AND HAVE INTRODUCED 15-20 POP FOR THE INLAND 2/3 OF THE
CWA. COVERAGE WILL BE ISOLATED THOUGH...NO LIGHTNING IS
FORECAST...AND MOST COMMUNITIES ARE EXPECTED TO REMAIN DRY. ANY
ACTIVITY WILL WANE SHORTLY AFTER DARK.

AS FAR AS HIGHS TODAY...HAVE HEDGED ON THE LOWER SIDE OF
GUIDANCE...MORE IN LINE WITH THE MET NUMBERS WHICH HAVE PERFORMED
BETTER AS OF LATE. THE E/SE FLOW WILL KEEP TEMPS FROM RISING MUCH
ABOVE SEASONABLE LEVELS...WITH HIGHS FORECAST TO BE AROUND 80 AT THE
BEACHES...AND AS HIGH AS 87/88 IN DARLINGTON/MARLBORO COUNTIES.
PARTLY CLOUDY SKY CONDITIONS TONIGHT THANKS TO SOME ADVECTION
STRATUS AND CONVECTIVE BLOWOFF WILL WORK IN TANDEM WITH CONTINUED
E/SE FLOW TO REDUCE NOCTURNAL COOLING. MINS WILL RANGE FROM ABOUT 65
WELL INLAND...TO ONLY ABOUT 70 FOR THE COAST. THESE ARE ABOUT 2-5
DEGREES ABOVE NORMAL FOR THE END OF MAY.

&&

.SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/...

AS OF 3 AM FRIDAY...MODELS CONTINUE TO SHOW THAT MOISTURE WILL TEND
TO REMAIN CONFINED TO FAR WESTERN ZONES AND FAIRLY SCANT AT THAT.
SURFACE AND LOW LEVEL ONSHORE FLOW WILL KEEP THE EASTERN THIRD OR
HALF OF THE AREA STABLE ON ACCOUNT OF THE COOLER SSTS AS WELL AS
KEEPING COASTAL LOCALES SEVERAL DEGREES COOLER DURING THE OTHERWISE
WARM AFTERNOONS BOTH DAYS. THE PATTERN HAS BEEN PRETTY BLOCKED UP
AND WILL CONTINUE TO DO SO FOR THE MOST PART. A LARGE UPPER LOW IS
LOCATED OVER THE WEST ATLANTIC WHILE THE SOUTHEAST REMAINS UNDER A
WEAKENING UPPER RIDGE.  TEMPERATURES WILL BE QUITE CLOSE TO THEIR
SEASONABLE NORMS, WITH INLAND LOCALES RUNNING JUST A BIT WARM IN THE
ABSENCE OF THE MARINE EFFECTS. UPPER TROUGHINESS WILL BE TAKING
SHAPE ACROSS THE LOWER MISSISSIPPI VALLEY BUT ITS EFFECTS LOCALLY
WILL HAVE TO WAIT UNTIL THE LONG TERM.

&&

.LONG TERM /MONDAY THROUGH THURSDAY/...

AS OF 3 AM FRIDAY... MONDAY MAY BE THE LAST DAY WHERE MEANINGFUL
RAINFALL CHANCES FAIL TO DEVELOP ACROSS THE AREA AND JUST SLIGHT
CHANCE POPS REMAIN FOR AREAS WELL INLAND. THE WEATHER TURNS
UNSETTLED AND LIKELY NOT AS WARM BY TUESDAY AS A BACKDOOR COLD FRONT
DROPS INTO THE AREA. MODELS ARE NOT IN TREMENDOUS AGREEMENT WHERE
THIS FRONT WILL BE COME WEDNESDAY BUT IT WILL LIKELY STILL BE
PROXIMAL ENOUGH TO BRING ANOTHER DAY OF FAIRLY UNSETTLED WEATHER.
THE FURTHER SOUTH GFS WOULD ALSO IMPLY A NOTICEABLE COOLDOWN. SOME
OF THE DEEPER MOISTURE WILL HAVE BEEN SHUNTED TO OUR SOUTH ON
THURSDAY BUT RAIN CHANCES STILL APPEAR WARRANTED WITH A NORTH-SOUTH
GRADIENT ACROSS THE REGION.


&&

.AVIATION /06Z FRIDAY THROUGH TUESDAY/...
AS OF 06Z...NO CONVECTION IS EXPECTED OVERNIGHT AS THINGS HAVE
STABILIZED. LITTLE TO NO FOG IS EXPECTED AS CROSSOVER TEMPERATURES
ARE NOT FORECAST TO BE REACHED AND CURRENT DEWPOINT DEPRESSIONS
REMAIN RATHER HIGH. HOWEVER...HAVE ADDED TEMPO MVFR AT CRE AND LBT
FOR LOCAL EFFECTS AND FORECAST MINS NEAR AFTN CROSSOVER DEWPOINTS,
RESPECTIVELY. OTHERWISE...VISIBILITY SHOULD REMAIN UNRESTRICTED
TONIGHT. VFR FORECAST AFTER SUNRISE WITH LIGHT E/SE WINDS 10 KTS OR
LESS AND ONLY VERY ISOLATED SHOWERS POSSIBLE...FAVORED AT THE INLAND
TERMINALS. HAVE OPTED TO KEEP ANY MENTION OF SHOWERS OUT OF THE TAFS
HOWEVER DUE TO EXPECTED ISOLATED NATURE. ANY SHOWERS WILL WANE AFTER
DARK WITH SIMILAR CONDITIONS TO TONIGHT FORECAST FOR FRIDAY NIGHT.

EXTENDED OUTLOOK...TYPICAL EARLY SUMMER PATTERN WITH MORNING FOG AND
MAINLY AFTERNOON ISOLATED/SCATTERED SHOWERS AND STORMS. OTHERWISE
EXPECT VFR.

&&

.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 300 AM FRIDAY...VERY LITTLE CHANGE IN THE MARINE CONDITIONS
THROUGH THE NEAR TERM. SURFACE HIGH PRESSURE CENTERED WELL NE OF THE
WATERS WILL MAINTAIN A RIDGE AXIS INTO THE SOUTHEAST. THIS PRODUCES
A WEAK PRESSURE GRADIENT...WITH WINDS WAVERING ONLY SLIGHTLY BETWEEN
E AND SE AT AROUND 10 KTS. CURRENT SEAS OF 2-3 FT WILL BUILD ONLY
SLIGHTLY TODAY...MORE DUE TO AN INCREASING E/SE SWELL THAN ANY WIND-
WAVE CONTRIBUTION. DOMINANT PERIODS ARE FORECAST TO INCREASE TO
AROUND 9 SEC...WITH THE SWELL AMPLITUDE BUILDING TO 4 FT LATER
TODAY. THIS WILL DRIVE WAVE HEIGHTS TO 3-4 FT...SLIGHTLY LOWER NEAR
SHORE WHERE MORE FRICTIONAL EFFECTS ARE FELT ON THIS LONGER PERIOD
WAVE.

SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/...

AS OF 3 AM FRIDAY...  A VERY LIGHT FLOW REGIME IN PLACE THROUGH THE
PERIOD. HIGH PRESSURE OVER THE WESTERN ATLANTIC WILL BE EXTENDING A
RIDGE AXIS INTO THE SOUTHEASTERN U.S. ON SATURDAY. THOUGH THE
GRADIENT WILL BE VERY WEAK THE FETCH WILL BE QUITE LONG. SMALL WIND
WAVES WILL COMBINE WITH SOME EASTERLY SWELL FOR A 3 TO 4 FT DOMINANT
WAVE HEIGHT. THE RIDGE AXIS RETREATS ON SUNDAY POSSIBLY BRINGING A
SLIGHT VEER AND INTERRUPTING THE FETCH LENGTH.

LONG TERM /MONDAY THROUGH THURSDAY/...

AS OF 3 AM FRIDAY... WEAK GRADIENT IN PLACE ON MONDAY WHILE PIEDMONT
TROUGH TRIES TO DEVELOP OVER LAND. SEAS MAY STILL BE HOVERING AROUND
3 FT MARK DUE TO RESIDUAL SWELL ENERGY FROM THE SHORT TERM. COLD
FRONT BRINGS A SHARP VEER AND PERHAPS A CATEGORY INCREASE IN SPEED
BUT NOT UNTIL TUESDAY NIGHT.

&&

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

&&

$$


NEAR TERM...JDW
SHORT TERM...MBB
LONG TERM...MBB
AVIATION...JDW



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