Area Forecast Discussion
Issued by NWS Wilmington, NC

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000
FXUS62 KILM 251019
AFDILM

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE WILMINGTON NC
618 AM EDT FRI JUL 25 2014

.SYNOPSIS...
A STALLED FRONT WILL BECOME INTERTWINED WITH THE SEABREEZE TODAY.
THE FRONT WILL LIFT NORTH AND DISSIPATE TONIGHT. HIGH PRESSURE WILL
FOLLOW AND BRING HOT...HUMID AND SULTRY CONDITIONS THIS WEEKEND AND
ON MONDAY. THE NEXT COLD FRONT WILL DROP ACROSS THE AREA TUESDAY. IN
ITS WAKE...COOLER AND DRIER CONDITIONS WILL OVERSPREAD THE AREA FOR
THE MIDDLE OF NEXT WEEK.

&&

.NEAR TERM /THROUGH TONIGHT/...
AS OF 600 AM FRIDAY...WATER VAPOR IMAGERY WAS SHOWING DRIER AIR
BEGINNING TO NOSE IT WAY INTO THE INTERSTATE 95 CORRIDOR THIS
MORNING. WSR-88D SHOWED SHOWERS DISSIPATING ACROSS THE GRAND STRAND
WITH A LARGE AREA OF SHOWERS AND THUNDERSTORMS MAINLY ACROSS THE
OFFSHORE WATERS.

A COLD FRONT HAS DROPPED INTO OUR NORTHERN AND WESTERN ZONES AND
WILL MEANDER ACROSS OUR FORECAST AREA THIS MORNING BEFORE BECOMING
INTERTWINED WITH THE SEABREEZE BOUNDARY THIS AFTERNOON. THE FRONT IS
EXPECTED TO LIFT BACK TO THE NORTH BEFORE DISSIPATING TONIGHT.
OUTFLOW BOUNDARIES LEFT OVER FROM DYING CONVECTION THIS MORNING WILL
BECOME BOUNDARIES OF CONVECTIVE INITIATION AS GREATER HEATING
COMMENCES LATER TODAY.

THE AIRMASS TODAY WILL NOT BE AS MOIST OR AS UNSTABLE AS ON THU. IN
FACT WITH TIME...THE MID LEVELS WILL DRY OUT FURTHER ACROSS INLAND
COMMUNITIES AND THEN AT THE COAST LATER THIS AFTERNOON. AS THIS
DRIER AIR ARRIVES...PRECIPITABLE WATER VALUES WILL DROP FROM NEAR 2
INCHES THIS MORNING TO NEAR AN INCH AND THREE-QUARTERS DURING THE
AFTERNOON. MIXED LAYER CAPE VALUES WILL GENERALLY BE IN THE RANGE OF
1000 TO 1500 J/KG. THE FLOW ALOFT WILL BE WEAKER THAN ON THU AND
FROM THE WEST. HOWEVER...GIVEN A SURFACE FRONT WILL BE IN THE AREA
TODAY AND A SEABREEZE BOUNDARY WILL DEVELOP THIS AFTERNOON AND WITH
CHANNELED VORTICITY AHEAD OF THE UPSTREAM MID-LEVEL TROUGH...WE DO
EXPECT MAINLY SCATTERED CONVECTION WITH PERHAPS A GREATER EMPHASIS
ACROSS OUR SOUTHERN AND COASTAL ZONES WHERE DEEPER MOISTURE WILL
HANG ON LONGEST. THE COVERAGE AND INTENSITY OF THE SHOWERS AND
THUNDERSTORMS SHOULD BE LESS THAN ON THU.

THE DAY WILL BEGIN CONSIDERABLY COOLER THAN 24 HOURS AGO. HIGHS
TODAY WILL BE AROUND 90...WITH MORE LOWER 90S ACROSS THE PEE DEE
REGION AND MORE UPPER 80S ALONG THE IMMEDIATE COAST. DEWPOINTS WILL
ALSO BE A LITTLE LOWER AND THIS WILL KEEP THE AFTERNOON HEAT INDEX
UNDER 100 DEGREES IN MOST PLACES. THE SOUTH SANTEE RIVER AREA HAS
THE HIGHEST RISK OF EXPERIENCING A HEAT INDEX OF 100 DEGREES THIS
AFTERNOON.

ANY CONVECTION STILL AROUND LATER IN THE AFTERNOON WILL COME TO AN
END THIS EVE AS THE AIRMASS SHOULD STABILIZE RATHER QUICKLY WITH
PRONOUNCED DRYING TAKING PLACE IN THE WAKE OF THE UPPER TROUGH. IN
FACT SKIES ARE EXPECTED TO BECOME PARTLY CLOUDY TO MOSTLY CLEAR
TONIGHT. WINDS WILL BE LIGHT. GIVEN THE GROUND WILL STILL BE WET IN
MANY PLACES...PATCHY TO PERHAPS AREAS OF FOG MAY DEVELOP AS TEMPS
COOL TO NEAR THE DEWPOINTS...LOWER TO MID 70S.

&&

.SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/...
AS OF 330 AM FRIDAY...MODELS CONTINUE WITH THE ONGOING LONGWAVE
UPPER PATTERN THIS PERIOD...WITH TROFFING ALOFT ACROSS THE
EASTERN 1/3RD OF THE U.S. AND RIDGING ALOFT FOR THE WESTERN 2/3RDS
OF THE U.S. THE UPPER TROF AXIS...NOT AS AMPLIFIED AS WAS EARLIER
IN THE WEEK...IS PROGGED TO A POSITION JUST OFF THE CAROLINA
COASTS...BASICALLY ALONG THE EASTERN SEABOARD. AT THE SFC...MODELS
INDICATE THE SFC FRONT WILL DECAY ACROSS THE AREA ON SATURDAY.
THIS WILL LEAVE THE FA UNDER WEAK RIDGING FROM THE ATL
WATERS...AND THE FORMATION OF THE PIEDMONT TROF ACROSS THE CENTRAL
CAROLINAS DURING SATURDAY.

FOR SUNDAY THRU SUNDAY NIGHT...THE MODELS REMAIN IN GOOD
AGREEMENT WITH THE AMPLIFICATION OF BOTH THE UPPER TROF
OVERHEAD...AND THE UPPER RIDGING THAT IS CURRENTLY AFFECTING THE
WESTERN 2/3RDS OF THE U.S. A S/W TROF IS PROGGED TO DIVE OUT OF
CENTRAL CANADA EARLY SUNDAY...AND BASICALLY AID IN THE
AMPLIFICATION PROCESS OF THE FLOW ALOFT ACROSS THE CONTERMINOUS
U.S. AT THE SFC...THE WEAK RIDGING FROM OFF THE COAST WILL GET
SHUNTED SOUTH OF THE AREA. THE PIEDMONT SFC TROF WILL GAIN SOME
STRENGTH AS MODELS CONTINUE WITH THE TIGHTENING OF THE GRADIENT
ASSOCIATED WITH THE PIEDMONT TROF.

THIS PERIOD WILL BE HIGHLIGHTED BY THE 3HS...HAZY HOT AND HUMID.
VERY LITTLE IN THE WAY OF CONVECTION IS EXPECTED EXCEPT FOR ISOLATED
CHANCES ALONG THE SEA BREEZE BOUNDARY...AND ANY CONVECTION THAT
DRIFTS TO THE FA AFTER FIRING UP ALONG THE PIEDMONT TROF. THUS
20-30 POPS ARE THE HIGHEST WILL GO THIS PERIOD. OVERALL...WARMER
TEMPS ALOFT AS WELL AS SUBSIDENCE ALOFT...WILL BOTH AID IN KEEPING
A LID ON CONVECTION THIS WEEKEND. VARIOUS MODEL MOS GUIDANCE DOES
PAINT WIDESPREAD 90+ DEGREE TEMPS FOR SATURDAY...AND EVEN HOTTER
ON SUNDAY. HAVE GONE ALONG WITH THESE NUMBERS ESPECIALLY WITH THE
DECENT W-NW DOWNSLOPE FLOW ALOFT. IN FACT...HEAT ADVISORY CRITERIA
WILL LIKELY BE MET ON SUNDAY WITH HIGHS WELL INTO THE 90S ALONG
WITH HUMIDITY LEVELS HAVING INCHED BACK UPWARDS. THUS THE 2
COMBINED PROVIDE FORECAST HEAT INDICES REACHING A WIDESPREAD
104-106 DEGREES ACROSS THE FA.

&&

.LONG TERM /MONDAY THROUGH THURSDAY/...
AS OF 300 PM THURSDAY...MID LEVEL TROUGH WILL DOMINATE MUCH OF THE
PERIOD KEEPING TEMPERATURES ACROSS THE REGION BELOW CLIMO. THE
EXCEPTION WILL BE ON SUN WITH MID LEVEL RIDGE TO THE WEST
EXTENDING EAST. 850 TEMPS WILL FLIRT WITH 20-22C WHICH SHOULD
PRODUCE HIGHS IN THE MID TO UPPER 90S. DESPITE THE HOT TEMPS DO NOT
THINK THERE WILL BE MUCH CONVECTION AROUND. WESTERLY MID LEVEL FLOW
AND SUBSIDENCE ON THE RIDGES PERIPHERY WILL KEEP MID LEVELS DRY.
CANNOT RULE OUT ISOLATED CONVECTION...ESPECIALLY LATER IN THE DAY
ASSOCIATED WITH THE PIEDMONT TROUGH BUT SEE NO REASON TO GO ABOVE
INHERITED SILENT POP.

COLD FRONT MOVES INTO THE AREA LATE MON...PUSHED BY IMPRESSIVE MID
LEVEL TROUGH. DOES NOT LOOK LIKE MON WILL BE AS HOT AS SUN GIVEN
INCREASED MID LEVEL MOISTURE AND MORE WIDESPREAD CONVECTION LATER IN
THE DAY...JUST AHEAD OF THE FRONT. SHOULD THE FRONT BE DELAYED A BIT
MON COULD END UP AS HOT AS SUN GIVEN 850 TEMPS HANGING IN THE LOW
20C RANGE FOR MUCH OF THE DAY. LATER MON INTO TUE WILL BE THE MOST
ACTIVE PART OF THE PERIOD CONVECTIVELY SPEAKING AND WILL MAINTAIN
INHERITED HIGH CHC POP.

MID LEVEL TROUGH AXIS WILL REMAIN WEST OF THE AREA THROUGH THE
PERIOD WITH THE FRONT STALLING NOT TOO FAR OFF THE COAST. INITIALLY
MID LEVELS ARE DRY BUT INCREASING MOISTURE ALOFT WILL RESULT IN A
SLOW INCREASE IN POP THROUGH THE MIDDLE OF NEXT WEEK. TEMPS WILL RUN
A LITTLE BELOW CLIMO LATE IN THE PERIOD.

&&

.AVIATION /06Z FRIDAY THROUGH TUESDAY/...
AS OF 06Z...ISOLATED TO SCATTERED SHOWERS WILL REMAIN IN THE
VICINITY OFF THE TAF SITES THROUGH 10Z OR SO.

MVFR/IFR IS POSSIBLE DUE TO PATCHY FOG ESPECIALLY INLAND TERMINALS.
BEST CONFIDENCE OF TEMPO LIFR WILL BE AT KLBT. VFR EXPECTED ALL
TERMINALS 12-13Z WITH LIGHT SW-WNW WINDS AT THE COASTAL TERMINALS
AND WNW-N WINDS AT KFLO. WINDS BECOME SE-SW AT THE COASTAL TERMINALS
LATE MORNING. SHRA/TSRA POSSIBLE AGAIN BY 18Z WITH BEST CONFIDENCE
OF TS OCCURRENCE AT THE COASTAL TERMINALS. CONVECTION DISSIPATES IN
THE EVENING WITH WINDS BECOMING LGT/VRBL.

EXTENDED OUTLOOK...SHOWERS/TSTMS/TEMPO MVFR POSSIBLE SUNDAY AND
MONDAY.

&&

.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 600 AM FRIDAY...A FRONT WILL BE NEARING THE WATERS THIS
MORNING AND THEN BECOME INTERTWINED WITH THE SEABREEZE THIS
AFTERNOON BEFORE LIFTING NORTH AND DISSIPATING TONIGHT. WINDS WILL
BE 10 KT OR LESS. WSW OR SW WINDS MAY BECOME LIGHT AND VARIABLE FOR
A TIME THIS MORNING. A S TO SW WIND DIRECTION IS EXPECTED THIS
AFTERNOON. SW WINDS SHOULD RETURN TONIGHT. SEAS OF 3 TO 4 FT WILL BE
SUBSIDING...REACHING TO 2 TO 3 FT THIS AFTERNOON AND 2 FT TONIGHT.

SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/...
AS OF 330 AM FRIDAY...FOR SATURDAY...THE AREA WATERS WILL BE
UNDER THE INFLUENCE OF A DECAYING FRONTAL BOUNDARY...RESULTING IN
MAINLY A VARIABLE WIND DIRECTION FOR MUCH OF THE DAY...AND WITH
THE LACK OF ANY GRADIENT...SPEEDS WILL GENERALLY BE 10 KT OR LESS.

FOR SUNDAY...THE AMPLIFYING FLOW ALOFT WILL RESULT IN A
STRENGTHENING SFC PIEDMONT TROF ACROSS THE CENTRAL CAROLINAS AND
THE RIDGING FROM THE BERMUDA HIGH BEING SHUNTED WELL SOUTH OF THE
AREA WATERS. THIS WILL PRODUCE A TIGHTENING SFC PG ACROSS THE
CAROLINAS INCLUDING THE COASTAL WATERS. THE SFC PRESSURE PATTERN
WILL YIELD A SFC SW-WSW WIND DIRECTION...WITH INCREASING SPEEDS
SUNDAY INTO SUNDAY NIGHT. SCEC AND/OR SCA CONDITIONS WILL LIKELY
BE MET SUNDAY AFTERNOON AND/OR NIGHT.

SIGNIFICANT SEAS WILL BE AT THEIR EBB DURING SATURDAY WITH AN ESE-
SE 1-3 FOOT GROUND SWELL DOMINATING THE WATERS. THE AFTN/EVENING SEA
BREEZE CIRCULATION WILL ADD SOME WIND CHOP NEAR SHORE. FOR
SUNDAY...LOOK FOR WIND DRIVEN WAVES TO STEADILY INCREASE IN BOTH
HEIGHT AND PERIODS...AND WILL LIKELY BE THE DOMINANT PLAYER IN THE
SIGNIFICANT SEAS FORMULA. WILL ADVERTISE 6 FOOTERS ACROSS THE
LOCAL WATERS LATE SUNDAY AFTERNOON BUT MORE LIKE SUNDAY NIGHT.

.LONG TERM /MONDAY THROUGH TUESDAY/...
AS OF 300 PM THURSDAY...MODEST SW FLOW ON SUN WILL INCREASE INTO MON
AS GRADIENT TIGHTENS AHEAD OF ADVANCING COLD FRONT. SPEEDS LATER SUN
MAY APPROACH SCEC THRESHOLDS AS PIEDMONT TROUGH STRENGTHENS. SCA
HEADLINES SEEM CERTAIN FOR AT LEAST MON AND POSSIBLY SUN NIGHT AS
PROLONGED STRONG SOUTHWEST FLOW BUILDS SEAS TO 4 TO 6 FT. FRONT
MOVES ACROSS THE WATERS MON NIGHT WITH NORTHERLY FLOW DEVELOPING.
GRADIENT RELAXES BEHIND THE FRONT AND SPEEDS WILL DROP UNDER 10 KT
BY MIDDAY TUE. FRONT ENDS UP STALLED JUST EAST OF THE WATERS WITH
THE PROXIMITY TO THE FRONTAL ZONE KEEPING GRADIENT WEAK AND WINDS
LIGHT AND VARIABLE. SEAS WILL DROP TO 3 TO 4 FT BEHIND THE FRONT AND
BELOW 3 FT BY THE END OF THE PERIOD.

&&

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

&&

$$

NEAR TERM...RJD
SHORT TERM...DCH
LONG TERM...III
AVIATION...RJD










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