Area Forecast Discussion
Issued by NWS Wilmington, NC

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000
FXUS62 KILM 231921
AFDILM

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE WILMINGTON NC
321 PM EDT WED JUL 23 2014

.SYNOPSIS...
BERMUDA HIGH PRESSURE WILL GIVE WAY TO A A COLD FRONT APPROACHING
FROM THE NORTHWEST TOMORROW. THIS FRONT WILL BECOME STATIONARY
OVER THE REGION THIS WEEKEND. A SECOND COLD FRONT WILL APPROACH
THE REGION MONDAY NIGHT INTO TUESDAY AND IT TO WILL STALL ALONG
THE COAST LATE TUESDAY AND WEDNESDAY.

&&

.NEAR TERM /THROUGH TONIGHT/...
AS OF 320 PM WEDNESDAY...PURELY SUNSHINE-DRIVEN CONVECTION IS
OCCURRING ACROSS EASTERN NORTH AND SOUTH CAROLINA THIS AFTERNOON.
EXCEPT FOR A "DRY" LAYER OF 60% RELATIVE HUMIDITY NEAR 700 MB THE
TROPOSPHERE IS VERY HUMID THROUGH ITS DEPTH AND PRECIPITABLE WATER
VALUES ARE NEAR 2.0 INCHES. TEMPERATURES IN THE UPPER 80S AND
LOWER 90S ARE GENERATING SURFACE-BASED CAPE NEAR 2000 J/KG AND
LIFTED INDICES AROUND -5 WITH NO CAPPING. LACK OF WIND SHEAR IS
FAVORING SINGLE-CELL STORMS WITH NO ORGANIZATION...AND THE BIGGEST
THREAT TODAY`S CONVECTION POSES IS BRIEF HEAVY RAINFALL AND
LIGHTNING. ACTIVITY SHOULD CONTINUE AS LONG AS THERE IS SURFACE-
BASED INSTABILITY PRESENT...LARGELY DECAYING IN THE 6-9 PM TIME
FRAME.

THE UPPER LOW THAT DIRECTED THE PLUME OF HUMID TROPICAL AIR
NORTHWARD INTO THE CAROLINAS EARLIER IN THE WEEK IS RETROGRADING
UNDERNEATH THE SOUTHWESTERN U.S. RIDGE AND IS NO LONGER A FACTOR IN
OUR WEATHER. HUMID AIR IS STILL SWINGING AROUND THE BERMUDA HIGH AND
ITS UPPER LEVEL CENTER OVER THE EASTERN BAHAMAS. WESTERLY FLOW
ACROSS THE SOUTHERN APPALACHIANS IS INDUCING DOWNSTREAM SURFACE
TROUGHING...AND THE PRESSURE PATTERN BETWEEN THIS SURFACE TROUGH
OVER THE PIEDMONT AND THE BERMUDA HIGH OFFSHORE WILL ENSURE A
SOUTHWEST WIND OVERNIGHT.

STRENGTHENING WINDS JUST ABOVE THE SURFACE SHOULD MAKE FOG LESS
LIKELY TONIGHT THAN EARLIER IN THE WEEK. LOWS SHOULD REACH A MUGGY
73-74 INLAND...AND 75-77 AT THE COAST.

&&

.SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
AS OF 320 PM WEDNESDAY...THURSDAY IS SETTING UP TO BE A HOT AND
STORMY AFTERNOON AND EVENING. THE THE SYNOPTIC SCALE A 500 MB
TROUGH AXIS WILL SHIFT TOWARD THE COASTAL CAROLINAS AND FORECAST
AREA WILL BE ON THE EAST SIDE OF THE TROUGH THROUGH THE PERIOD. AT
THE SURFACE A COLD FRONT IS EXPECTED TO SHIFT TO THE COAST FRIDAY
EVENING. AHEAD OF THIS FRONT WITH A WEST SOUTHWESTERLY WINDS
TEMPERATURES ARE EXPECTED TO REACH MID 90S ESPECIALLY IN INLAND
NORTHEAST SOUTH CAROLINA. THESE TEMPERATURES COMBINED WITH THE
DEW POINT IN THE LOWER 70S WILL PRODUCE HEAT INDICES VALUES IN THE
100 TO 103 DEGREE RANGE ESPECIALLY INLAND AREAS.

FOR STORMS WITH THE FRONTAL BOUNDARY COMING ACROSS A A WEAK MID
LEVEL JET CAN NOT RULE OUT STRONG WINDS WITH THE STORMS BUT THE
HIGH PRECIPTABLE WATERS OF OVER 2 INCHES WILL ME HEAVY DOWNPOURS
ARE POSSIBLE AND ISOLATED FLOODING IS POSSIBLE.

FOR FRIDAY...WITH THE FRONT IN THE REGION AND CLOUD COVER EXPECT A
CHANCE OF THUNDERSTORMS BUT HIGH TEMPERATURES WILL BE IN THE UPPER
80S TO NEAR 90.

&&

.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
AS OF 320 PM WEDNESDAY...A WEAK UPPER IMPULSE CROSSES THE REGION ON
SATURDAY WHILE PIEDMONT TROUGH/FRONTAL REMAINS SIT TO OUR WEST.
TOUGH TO COMPLETELY RULE OUT ISO CONVECTION IN SUCH A SETUP BUT MID
LEVELS REMAIN TOO DRY FOR ANY MORE COVERAGE THAN THAT. MUCH THE
SAME WILL APPLY ON SUNDAY...AND BOTH DAYS WILL LIKELY OFFER UP
FAIRLY SEASONABLE TEMPERATURES. SUNDAY NIGHT INTO MONDAY MAY START
GETTING ACTIVE AS MID LEVEL CYCLONIC FLOW AND SURFACE COLD FRONT
APPROACH FROM THE NW...BOTH IN RESPONSE TO UNSEASONABLY STRONG
TROUGHINESS DEVELOPING IN THE GREAT LAKES. THIS FRONT PUSHES THROUGH
MONDAY NIGHT INTO TUESDAY MORNING. SOME COOLER AND DRIER AIR WILL
THEN FILTER IN BEHIND IT FOR THE MIDWEEK PERIOD. EXCEPTION MAY BE
ALONG THE COAST WHERE SUFFICIENT MOISTURE MAY LINGER FOR SMALL RAIN
CHANCES.

&&

.AVIATION /18Z WEDNESDAY THROUGH MONDAY/... AS OF 18Z...VISIBLE
SATELLITE IMAGERY SHOWS ENHANCED CU DEVELOPMENT ALONG THE SEA
BREEZE WHICH WILL PRODUCE SHOWERS IN THE VICINITY OF THE COASTAL
TERMINALS THROUGH MID AFTERNOON. BAND OF SCATTERED CONVECTION WILL
ALSO AFFECT FLO/LBT FOR THE NEXT FEW HOURS...AND BASED ON CURRENT
RADAR TRENDS...LBT IS THE MOST LIKELY TERMINAL TO ENCOUNTER A TSTM
OVER THE NEXT FEW HOURS. EXPECT CONVECTION TO DIMINISH WITH THE
LOSS OF AFTERNOON HEATING. SCATTERED SHOWERS AND THUNDERSTORMS ARE
EXPECTED TO DEVELOP AND MOVE IN FROM THE NORTHWEST BEGINNING LATE
THURSDAY MORNING. FOR NOW HAVE LIMITED INCLUSION TO LBT WHERE
CHANCES BEFORE 18Z THURSDAY LOOK BEST OUT OF ALL THE AREA
TERMINALS.

EXTENDED OUTLOOK...A COLD FRONT WILL APPROACH THE AREA THURSDAY AND
LINGER INTO FRIDAY...INCREASING THE CHANCE OF SHOWERS/TSTMS. ANOTHER
COLD FRONT WILL APPROACH LATE MONDAY AND STALL NEAR THE COAST
THROUGH WEDNESDAY...ALSO INCREASING THE CHANCE OF CONVECTION.
MVFR/IFR CIGS/VIS POSSIBLE MAINLY IN TSTMS.

&&

.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 320 PM WEDNESDAY...BERMUDA HIGH PRESSURE WELL OFF THE SOUTHEAST
COAST HAS TURNED OUR SURFACE WINDS SOUTH-SOUTHWESTERLY THIS
AFTERNOON...AND A STEADY SOUTHWEST WIND IS EXPECTED TO CONTINUE
OVERNIGHT. WIND SPEEDS AT THE BEACHES SHOULD INCREASE TO 12-15 KNOTS
LATE THIS AFTERNOON WITH THE SEABREEZE...AND A SOLID 15 KNOTS IS
EXPECTED OVERNIGHT AWAY FROM SHORE DUE TO THE STRONGER GRADIENT
BETWEEN THE HIGH OFFSHORE AND A LOW PRESSURE TROUGH ACROSS THE NC/SC
PIEDMONT REGION. SEAS CURRENTLY 2-3 FEET IN A COMBINATION OF AN 8
SECOND SOUTHEAST SWELL AND SHORTER PERIOD WIND WAVES MAY BUILD TO 4
FEET OVERNIGHT...ESPECIALLY EAST OF CAPE FEAR WHERE THE WIND FETCH
WILL BE LONGEST.



SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
AS OF 320 PM WEDNESDAY...WINDS WILL BE FROM THE SOUTHWEST THROUGH
THE PERIOD WITH AN INCREASE IN WINDS AS A SURFACE COLD FRONT
APPROACHES THE WATERS BUT STALLS JUST ON SHORE. WHEN THE FRONT
STALL THE WINDS WILL WEAKEN JUST A BIT. A SEA HEIGHTS ARE EXPECTED
TO INCREASE TO 3 TO 4 FEET ON THURSDAY AND THEN SETTLE BACK TO 2
TO 3 FEET RANGE ON FRIDAY.


LONG TERM /SATURDAY THROUGH MONDAY/...
AS OF 320 PM WEDNESDAY...SATURDAY WILL BRING FAIRLY TYPICAL
CONDITIONS FOR THE TIME OF YEAR...A SOUTHWESTERLY FLOW RESULTING
FROM WEST ATLANTIC HIGH PRESSURE AND A WEAK PIEDMONT
TROUGH/FRONTAL BOUNDARY INLAND. A SHARPENING OF THE LATTER ON
SUNDAY WILL TIGHTEN THE FLOW AND SEAS COULD BUILD TO ADVISORY
LEVELS. THE APPROACH OF AN UNSEASONABLY STRONG COLD FRONT ON
MONDAY WILL FURTHER TIGHTEN THE GRADIENT AND AN ADVISORY APPEARS
EVEN MORE LIKELY. BOTH DAYS ARE A TOUGHER CALL OVER SRN ZONES
WHERE 6 FT SEAS MAY HAVE A HARDER TIME GETTING CLOSE ENOUGH TO
SHORE TO BE IN THE 20NM FORECAST ZONES.



&&

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

&&

$$

NEAR TERM...TRA
SHORT TERM...HAWKINS
LONG TERM...MBB
AVIATION...CRM






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