Area Forecast Discussion
Issued by NWS Wilmington, NC

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000
FXUS62 KILM 211731
AFDILM

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE WILMINGTON NC
131 PM EDT THU AUG 21 2014

.SYNOPSIS...
HOT AND HUMID CONDITIONS CAN BE EXPECTED OVER THE NEXT COUPLE OF
DAYS AS AN UPPER RIDGE EXPANDS INTO THE CAROLINAS. A HEAT ADVISORY
IS IN EFFECT FOR PORTIONS OF SOUTH CAROLINA THIS AFTERNOON. SLIGHT
COOLING THIS WEEKEND WILL ARRIVE AS A COLD FRONT PASSES THROUGH.
SURFACE HIGH PRESSURE BUILDING FROM THE NORTH EARLY NEXT WEEK WILL
KEEP RAIN CHANCES ON THE LOW SIDE.

&&

.NEAR TERM /THROUGH TONIGHT/...
AS OF 130 PM THURSDAY...STAGGERING HUMIDITY/TD VALUES SCRAPING
THE COAST WITH OPPRESSIVE APPARENT TEMPERATURE TRENDS ANTICIPATED.
HEAT ADVISORIES POSTED FOR OUR SC INTERIOR AS T/TD PAIRINGS BRING
HEAT INDICES/MAXIMUM APPARENT TEMPERATURES OF 105-108 DEGREES IN
AFTERNOON HOURS.

CONVECTION TODAY PARTIALLY SUPPRESSED ALOFT BY A SUBSIDING SLAB
OF DRIER AIR AS THICKNESSES MOUNT BENEATH THE EXPANDING UPPER
RIDGE INTO THE CAROLINAS FROM THE SW. INTENSE LOW- LEVEL HEATING
WILL SHARPEN OUR LOWER TROP LAPSE RATES BUT -5 TO -6 DEGREES AT
500 MB WILL SUPPRESS ANY EVOLVING UPDRAFTS GENERALLY OF MAGNITUDE
TO CAP SEVERE TSTMS TODAY. THE ONLY EXCEPTION...PULSE SEVERE IN
COLLIDING BOUNDARIES...AS THE SEA BREEZE FRONT ITSELF BECOMES
STRENGTHENED IN THE MIDDLE AFTERNOON TO EARLY EVENING. PWAT VALUES
REMAIN ELEVATED AT AROUND 1.75 INCHES WITH LOTS OF BOTTOM-LOADED
MOISTURE SO VERY HEAVY RAIN AT TIMES POTENTIALLY.

SURFACE ANALYSIS SHOWS A WEAK BUT CONSEQUENTIAL SURFACE BOUNDARY
BI-SECTING NE SC/SE NC FROM SW TO NE PRESENTLY...AND THIS FEATURE
AS IT BECOME INTERACTIVE WITH THE ADVANCING SEA-BREEZE FRONT COULD
SPARK OUR CONVECTION LATER TODAY NEAR THE COAST OR COASTAL INTERIOR
TRACKING TO THE E GENERALLY.

&&

.SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/...
AS OF 3 AM THURSDAY...FORECAST CONTINUES TO BE PLAYING CATCH-UP. THE
RELATIVELY LOW AMPLITUDE BUT NEVERTHELESS STALWART MID AND UPPER
RIDGE OVER THE LOWER MS VALLEY WILL REMAIN IN PLACE. FOR DAYS NOW
GUIDANCE HAS BEEN SHOWING THAT SOME ENERGY TOPS THE NE OF THIS RIDGE
AND DIVES INTO THE CAROLINAS. IN FACT NOW WITH THE RIDGE EXPECTED TO
GAIN AMPLITUDE INTO THE OHIO VALLEY AND UPPER  MS VALLEY THROUGH THE
PERIOD IT SEEMS THAT ANY OF THE AFOREMENTIONED ENERGY WILL TEND TO
BYPASS US BY TO THE NORTH. A PIEDMONT TROUGH WILL BE DISPLACED
TOWARDS THE COAST AND THE SEABREEZE WILL MAKE LITTLE INLAND PROGRESS
AND BOTH MAY FIRE ISOLATED CONVECTION...BUT NOW THE PERIOD APPEARS
TO BE LARGELY CHARACTERIZED BY A CONTINUATION OF UNSEASONABLY HOT
AND HUMID CONDITIONS ALTHOUGH A SLIGHT ABATEMENT OF BOTH MAY CREEP
IN ON SATURDAY. HEAT ADVISORY APPEARS POSSIBLE FOR PART OF THE AREA
ON FRIDAY. THIS WILL HINGE ON THE COLD FRONT THAT MAY COME THROUGH
SATURDAY OR NOT TIL SATURDAY NIGHT. WILL SHOW A SLIGHT DECREASE IN
TEMPS SATURDAY AS MOST MODELS ARE A LITTLE FASTER. THE SLOW GFS
THOUGH IMPLIES THAT MANY AREAS MAY COOK AGAIN SATURDAY AFTERNOON.
TAKE MAV HIGHS FOR LBT FOR EXAMPLE THURSDAY, FRIDAY, SATURDAY; 97,
96, 98. DON`T WANT TO SHOW MUCH OF A COOL DOWN IN CASE SOMETHING
LIKE THAT COMES TO PASS WHICH GIVEN RECENT MODEL ERRORS CERTAINLY
SEEMS POSSIBLE...AS THE SLOWER GFS COULD IMPLY THAT SOME LOCALES
WILL BE LOOKING AT YET ANOTHER HEAT ADVISORY.

&&

.LONG TERM /SUNDAY THROUGH THURSDAY/...
AS OF 3 AM THURSDAY...UPPER TROUGH OFF THE NE AND MID ATLANTIC COAST
FINALLY SHARPENS ENOUGH TO DRIVE COOL FRONT SOUTH OF THE AREA BY
SUNDAY. THE REMAINDER OF THE PERIOD WILL SEE THE MID LEVEL RIDGE
EXPAND EASTWARD WITH A NE TO SW ELONGATION FROM THE NEW ENGLAND
STATES TO THE GOMEX. AT THE SURFACE HIGH PRESSURE WILL SPILL DOWN
THE EAST FACE OF THE APPALACHIANS IN A PRESSURE PATTERN MORE
REMINISCENT OF THE COOL SEASON. LITTLE TO NO REAL RAIN CHANCES AND
TEMPS SEASONABLE. IT ALSO BEARS MENTIONING AT THIS POINT THAT THE
SYSTEM JUST EAST OF THE WINDWARD ISLANDS WILL LIKELY BE A TROPICAL
SYSTEM WELL OFF THE EAST COAST LATE IN THE PERIOD. SWELLS FROM THIS
SYSTEM COULD BE AFFECTING AREA BEACHES BY WEDNESDAY OR SOON
THEREAFTER.

&&

.AVIATION /18Z THURSDAY THROUGH TUESDAY/...
AS OF 18Z...SEA BREEZE ACTIVITY UNDERWAY NEAR THE N COAST. WILL
ADD TEMPO GROUP FOR A FEW HOURS ALONG THE COAST. BRIEF HEAVY RAIN
PROBABLE. TONIGHT...LIGHT WINDS WITH SOME LIGHT FOG POSSIBLE AFTER
MIDNIGHT. THE NAM HAS A CONVECTIVE COMPLEX COMING OVER THE
MOUNTAINS...AFFECTING THE NORTHERN TERMINALS OVERNIGHT HOWEVER
CONFIDENCE IS RATHER LOW WITH THIS SCENARIO. FRIDAY...A BIT MORE
SUBSIDENCE THAT PREVIOUS DAY. PROBABLY WILL SEE SOME ISOLATED
CONVECTION...BUT THAT`S ABOUT IT.

EXTENDED OUTLOOK...CHC AFTERNOON/EVENING SHRA/TSRA THROUGH THE
SUNDAY. VFR MONDAY. SHOWERS POSSIBLE NEAR THE COAST TUESDAY.

&&

.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 130 PM THURSDAY...THE N-S SFC TROF EXTENDING ACROSS THE
EASTERN CAROLINAS AND WEAK BERMUDA RIDGING EXTENDING WEST TO THE
SE U.S. COAST...WILL COMBINE EFFORTS TO CONTINUE WITH A SW WIND
ACROSS THE AREA WATERS...POSSIBLY VEERING SLIGHTLY TO THE WSW
NORTHERN PORTIONS TONIGHT. THE SFC PG REMAINS RATHER RELAXED WITH
WIND SPEEDS AROUND 10 KT THRUOUT THIS PERIOD. THE SEA BREEZE
CIRCULATION MAY TEMPORARILY PRODUCE 10-15 KT WIND SPEEDS NEAR
SHORE DURING THIS AFTN AND EARLY EVENING. LOOK FOR SIGNIFICANT
SEAS OF 2 TO 3 FT...WITH 3 FT POSSIBLY BEING A BIT TOO GENEROUS.
NEVERTHELESS...AN ESE 1-2 FOOT 8-9 SECOND PERIOD GROUND SWELL WILL
REMAIN PREVALENT AND LIKELY THE DRIVER OF SIGNIFICANT SEAS DURING
THIS PERIOD EXCEPT FOR THE WIND CHOP FROM THE SEA BREEZE.

SHORT TERM /FRIDAY THOUGH SATURDAY NIGHT/...
AS OF 3 AM THURSDAY...THE PIEDMONT THROUGH WILL BE DISPLACED TOWARDS
THE COAST FROM ITS NORMAL POSITION ON FRIDAY WITH SOME MODELS EVEN
PORTRAYING IT RIGHT ALONG THE COASTLINE. EITHER WAY THIS WILL FAVOR
VERY LIGHT SOUTHWESTERLY WINDS AND SEAS OF NO MORE THAN 2 TO 3 FT.
THE SEABREEZE WILL NOT BE VERY STRONG DUE TO OFFSHORE WINDS JUST
ABOVE THE SURFACE LAYER. SATURDAY IS ONE OF THE MORE UNCERTAIN
PERIODS OF BOTH THE SHORT TERM AS WELL AS THE LONG TERM. A COLD
FRONT WILL BE BACKDOORING ITS WAY SOUTH ACROSS THE AREA BUT ITS
TIMING IS POORLY AGREED UPON BY MODELS AND THIS HAS BEEN THE CASE
FOR SEVERAL DAYS NOW. FROPA TIMINGS CAN RANGE FROM SATURDAY TO
SATURDAY NIGHT. BEING AN EAST-WEST ORIENTED COLD FRONT IT SHOULD
LEAD TO A PRETTY ABRUPT WIND CHANGE FROM WEST TO EAST VIA CLOCKWISE
VEERING. FORTUNATELY WIND SPEEDS WILL REMAIN MINIMAL THROUGH THE
FROPA AND WAVES WILL NOT GROW IN SIZE EVEN THOUGH THEY MAY STEEPEN
UP.


LONG TERM /SUNDAY THROUGH MONDAY/...
AS OF 3 AM THURSDAY...EAST OR NORTHEAST WINDS IN STORE FOR THE
PERIOD AS COLD FRONT SAGS OFF TO THE SOUTH. HIGH PRESSURE BUILDS IN
FROM POINTS NORTH AND EAST AS MORE TYPICALLY SEEN IN COOLER WEATHER
SEASONS. SEAS WILL BUILD AND BECOME RATHER CHOPPY AND AN ADVISORY IS
NOT OUT OF THE QUESTION BY THE END OF THE PERIOD AT LEAST ACCORDING
TO WNA GUIDANCE. ANY EFFECTS FROM THE WOULD-BE TROPICAL SYSTEM THAT
WILL LIKELY REMAIN WELL OFFSHORE TO BE SLATED FOR THE MID WEEK AT
THE EARLIEST.

&&

.ILM WATCHES/WARNINGS/ADVISORIES...
SC...HEAT ADVISORY UNTIL 6 PM EDT THIS EVENING FOR SCZ023-032-033-
     039-053>056.

NC...NONE.
MARINE...NONE.

&&

$$

SYNOPSIS...COLBY
NEAR TERM...COLBY
SHORT TERM...BACON
LONG TERM...BACON
MARINE...DOUGH/BACON
AVIATION...DAVE/8




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