-- Discussion containing changed information from previous version are highlighted. --
000
FXUS62 KILM 231726
AFDILM

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

.SYNOPSIS...
BERMUDA HIGH PRESSURE WILL BUILD INTO THE AREA TODAY. A COLD FRONT
WILL APPROACH FROM THE NORTHWEST THURSDAY...STALLING NEAR THE COAST
FOR THE WEEKEND. ANOTHER COLD FRONT WILL APPROACH FROM THE NORTHWEST
MONDAY OR TUESDAY.

&&

.NEAR TERM /THROUGH TONIGHT/...
-- Changed Discussion --
AS OF 100 PM WEDNESDAY...AN EXTENSIVE CUMULUS FIELD HAS DEVELOPED
ALL THE WAY DOWN TO THE BEACHES. UNCAPPED INSTABILITY ON THE ORDER
OF 1500 J/KG WILL INCREASE TO 2000 J/KG IN THE NEXT FEW HOURS. RADAR
SHOWS CONVECTIVE ACTIVITY ALREADY ONGOING NEAR FAYETTEVILLE AND ALSO
ACROSS THE WESTERN PEE DEE COUNTIES OF SOUTH CAROLINA. IF THERE IS
ANY SUBSIDENCE AND DRYING/CAPPING ALOFT FROM THE OFFSHORE CONVECTION
IT MUST BE SUBTLE AS THE CUMULUS OUTSIDE THE WEATHER OFFICE HERE IN
WILMINGTON ARE SHOWING PRETTY EXTENSIVE VERTICAL GROWTH. I HAVE
INCREASED POPS TO 30 PERCENT WITH A FEW 40 PERCENT SPOTS DOWNSTREAM
OF CURRENT ACTIVITY ON RADAR AND CLOSER TO THE COAST WHERE IT
APPEARS LOW-LEVEL CONVERGENCE WILL BE MAXIMIZED DUE TO SEABREEZE
INTERACTIONS. PREVIOUS DISCUSSION FROM 1000 AM FOLLOWS...

INLAND FOG HAS BECOME A LOW STRATOCUMULUS DECK SINCE SUNRISE AND
SHOULD LIFT FURTHER INTO A CUMULUS DECK OVER THE NEXT HOUR. THIS
MOISTURE WILL BE THE SEED FOR SCATTERED THUNDERSTORMS THIS AFTERNOON
WITH COVERAGE AVERAGING ABOUT 30 PERCENT OF THE FORECAST AREA.
SYNOPTICALLY THE OLD STATIONARY FRONT NEAR THE COAST IS NEARLY GONE
WITH BERMUDA HIGH PRESSURE OFFSHORE EXPECTED TO TURN SURFACE WINDS
SOUTHWESTERLY LATER TODAY. A LANDBREEZE PUSHED OFFSHORE BEFORE
SUNRISE WITH LIGHT WEST TO NORTHWEST WINDS OBSERVED AT THE BEACHES.
THE DAYTIME SEABREEZE WILL TURN THESE WIND DIRECTIONS SOUTH TO
SOUTHWESTERLY BY EARLY AFTERNOON.

THE AIRMASS REMAINS QUITE MOIST WITH PRECIPITABLE WATER VALUES NEAR
2.0 INCHES AND SURFACE DEWPOINTS 72-75 DEGREES. LIGHT STEERING FLOW
AND MODEST LAPSE RATES ALOFT WILL LIMIT THE COVERAGE AND DEVELOPMENT
OF STORMS TODAY...BUT VIRTUALLY ALL MODEL GUIDANCE SHOWS THERE
SHOULD BE SOME CONVECTIVE ACTIVITY OUT THERE THIS AFTERNOON. A
LIMITING FACTOR THAT WILL STILL BE IN PLAY IS THE PRESENCE OF
WIDESPREAD CONVECTION OVER THE GULF STREAM OFF THE GA-SC-NC COAST.
SUSTAINED RISING MOTION WITHIN THIS CONVECTION WILL LEAD TO A
CORRESPONDING RING OF SUBSIDENCE AROUND THE EDGE...INCLUDING OVER
THE COASTAL CAROLINAS. FOR THIS REASON MY FORECAST POPS REMAIN BELOW
THE GFS/NAM MOS CONSENSUS TODAY.

I HAVE BUMPED FORECAST HIGHS UP A BIT WITH LOWER 90S FORECAST INLAND
AND UPPER 80S AT THE COAST. WITH DEWPOINTS PROBABLY REMAINING IN THE
LOWER 70S EVEN DURING PEAK HEATING WE COULD SEE HEAT INDICES REACH
100 DEGREES IN SPOTS THIS AFTERNOON.
-- End Changed Discussion --

&&

.SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
AS OF 330 AM WEDNESDAY...SOME DRIER AIR STREAMING IN INITIALLY
ON THURS WITH SOUTHWEST FLOW AND PCP WATER VALUES DOWN AROUND 1.5
INCHES BUT AS THE DAY PROGRESSES A COLD FRONT WILL MOVE INTO AND
SLOWLY THROUGH THE CAROLINAS. AS THE FRONT APPROACHES FROM THE
NORTHWEST THE GRADIENT WILL TIGHTEN WITH GUSTY SW WINDS AND
INCREASING LOW LEVEL WINDS UP TO 30 KTS. MOISTURE POOLS AHEAD OF
THE FRONT WITH INCREASED CONVECTIVE ACTIVITY BY LATE THURS AS PCP
WATER VALUES REACH UP OVER 2 INCHES. EXPECT MOST WIDESPREAD
SHWR/TSTM ACTIVITY BY LATE THURS AFTN AS PRE FRONTAL TROUGH NEARS
THE AREA AND GREATEST SHORTWAVE ENERGY RIDES AROUND THE BASE OF
THE H5 TROUGH THROUGH THE CAROLINAS. THE BEST UPPER LEVEL SUPPORT
WILL LAY JUST WEST OF LOCAL FORECAST AREA ON THURS AFTN BUT
HEADING INTO THURS NIGHT...STEERING FLOW WILL VEER TO BECOME MORE
SW TO W AND SHOULD SEE A FAIR AMOUNT OF CONVECTION INTO OUR AREA.
THE FRONT WILL GET HUNG UP OVER THE COASTAL CAROLINAS AND SHOULD
SEE FRIDAY MORE ACTIVE ALONG THE COAST WHILE DRIER AIR WILL MAKE
ITS WAY IN ACROSS INLAND AREAS. THE MID TO UPPER TROUGH SHIFTS OFF
THE COAST THROUGH FRI NIGHT BEFORE IT LIFTS OFF TO THE NORTHEAST
LEAVING A DEEPER DRIER FLOW AND INCREASED SUBSIDENCE HEADING INTO
EARLY SATURDAY.

DECENT WESTERLY DOWNSLOPE COMPONENT TO THE WINDS WITH LOW LEVEL
THICKNESSES PEAKING THURS. EXPECT HIGH TEMPS TO REACH INTO THE 90S
AND WITH DEWPOINT TEMPS INTO THE 70S...TEMPS WILL FEEL AS IF THEY
ARE OVER 100 DEGREES IN PLACES ESPECIALLY ACROSS NORTHEAST SOUTH
CAROLINA. AS TROUGH DIGS DOWN AND HEIGHTS LOWER FOR
FRIDAY...EXPECT TEMPS TO BE A FEW DEGREES LOWER BUT STILL UP
AROUND 90. CLOUDS AND INCREASED SHWR ACTIVITY WILL AFFECT THE
TEMPS ESPECIALLY LATE THURS THROUGH EARLY FRI. LOW TEMPS BOTH
NIGHTS WILL BE IN THE MID 70S.

&&

.LONG TERM /SATURDAY THROUGH TUESDAY/...
AS OF 330 AM WEDNESDAY...LINGERING COLD FRONT MAY REMAIN NEAR
THE COAST AS IT WEAKENS LEAVING WEAK HIGH PRESSURE OVER THE AREA
FOR THE WEEKEND. ALTHOUGH THE SURFACE BOUNDARY REMAINS CLOSE
BY...ENOUGH DRY AIR WILL MAKE ITS WAY INTO THE AREA IN WESTERLY
FLOW ALOFT WITH COLUMN MOISTURE APPRECIABLY LOWER ABOVE H85. PCP
WATER VALUES WILL BE DOWN NEAR 1.5 INCHES THROUGH SATURDAY AND
EVEN LOWER INLAND. THE GRADIENT WILL RELAX AS THE FRONT SHIFTS
SOUTH AND EAST AND WEAKENS THROUGH SATURDAY. MID TO UPPER TROUGH
LIFTS FAR ENOUGH OUT OF AREA AND ALTHOUGH A BROAD TROUGH REMAINS
OVER THE GREAT LAKES...HEIGHTS WILL RISE OVER THE CAROLINAS AS
RIDGE TRIES TO NOSE INTO THE SOUTHEAST THROUGH THE WEEKEND.
OVERALL EXPECT A GOOD DEAL OF SUNSHINE THROUGH THE WEEKEND WITH
LOWER POPS IN MORE LOCALIZED SHWR ACTIVITY AND WARM TEMPS.

BY LATE SUNDAY INTO MONDAY THE MID TO UPPER TROUGH BEGINS TO DIG
SOUTH AGAIN PUSHING ANOTHER COLD FRONT EAST INTO THE CAROLINAS.
THEREFORE SHOULD SEE ANOTHER ROUND OF INCREASED CONVECTIVE
ACTIVITY ACROSS THE AREA AHEAD AND ALONG THE COLD FRONT AS IT
MOVES THROUGH THE COASTAL CAROLINAS MONDAY INTO EARLY TUES. LOOKS
LIKE THE MAIN H5 TROUGH AXIS WILL SHIFT OFF THE COAST TUES PUSHING
FRONT FAR ENOUGH EAST TO ALLOW FOR DEEPER DRIER AIR TO MOVE INTO
THE AREA AS HIGH PRESSURE BUILDS IN FOR MID WEEK. THE MAIN TROUGH
WILL CONTINUE TO PLAGUE THE EAST COAST WITH LOWER HEIGHTS AND
TEMPS PUSHED TO THE COOLER SIDE OF CLIMO FOR MID WEEK NEXT WEEK.
TEMPS WILL START OUT ABOVE NORMAL IN A WARM AND HUMID AIR MASS
WITH READINGS IN THE 90S FOR HIGHS THROUGH MUCH OF THE WEEKEND BUT
BY TUES MAX TEMPS WILL BE IN THE 80S MOST PLACES WITH DEWPOINT
TEMPS DROPPING INTO THE 60S.

&&

.AVIATION /18Z WEDNESDAY THROUGH MONDAY/...
-- Changed Discussion --
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.
-- End Changed Discussion --

&&

.MARINE...
-- Changed Discussion --
NEAR TERM /THROUGH TONIGHT/...
AS OF 100 PM WEDNESDAY...NO SIGNIFICANT CHANGES ARE NEEDED TO THE
FORECAST EARLY THIS AFTERNOON. THE SEABREEZE HAS DEVELOPED ACCORDING
TO PIER/COASTAL OBSERVATIONS FROM TOPSAIL BEACH...WRIGHTSVILLE BEACH
AND OAK ISLAND. PREVIOUS DISCUSSION FROM 1000 AM FOLLOWS...

MORE TYPICAL MID-SUMMER WEATHER WILL DEVELOP TODAY AS THE OLD
STATIONARY FRONT OF THE PAST TWO DAYS DISSIPATES AND BERMUDA HIGH
PRESSURE WELL OFFSHORE TAKES HOLD. A WEAK LANDBREEZE PUSHED OFFSHORE
BEFORE SUNRISE PRODUCING WEST TO NORTHWEST WINDS ACROSS THE COASTAL
WATERS. THESE WIND DIRECTIONS SHOULD TURN BACK ONSHORE THIS
AFTERNOON WITH THE SEABREEZE...WITH WIND SPEEDS INCREASING TO NEAR
15 KNOTS BY EARLY EVENING. THE OVERALL PRESSURE GRADIENT SHOULD
TIGHTEN OVERNIGHT WITH 12-16 KNOT WINDS EXPECTED THROUGH MUCH OF THE
NIGHT.

SEAS CURRENTLY CONSIST ALMOST EXCLUSIVELY OF A 7-8 SECOND SOUTHEAST
SWELL AROUND 3 FT...PERHAPS CLOSER TO 2 FEET ALONG THE SOUTH
CAROLINA COAST WHERE WE HAVE NO BUOY DATA. A LITTLE MORE WIND CHOP
SHOULD DEVELOP ON TOP BY THIS EVENING...WITH COMBINED SEAS AVERAGING
3-4 FEET AWAY FROM SHORE.

SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
AS OF 330 AM WEDNESDAY...COLD FRONT WILL MOVE SLOWLY THROUGH THE
CAROLINAS LATE THURS INTO FRIDAY BEFORE STALLING OUT NEAR THE
COAST ON FRI. OVERALL SHOULD SEE A TIGHTENED GRADIENT FLOW OUT OF
THE SOUTHWEST UP TO 15 TO 20 KTS LATE THURS INTO EARLY FRI. SEAS
AROUND 2 TO 4 FT EARLY THURS WILL BUILD UP TO 3 TO 5 FT BY THURS
EVE AND POSSIBLY REACHING CLOSE TO SCA THRESHOLDS THURS EVE. WINDS
AND SEAS WILL DIMINISH THROUGH FRIDAY AS FRONT WEAKENS ALONG THE
CAROLINA COAST. MAY SEE A PERIOD OF MORE W WINDS ON FRI DEPENDING
ON HOW CLOSE THE FRONT MAKES IT BEFORE COMING BACK AROUND TO THE
S-SW THROUGH THE WEEKEND.

LONG TERM /SATURDAY THROUGH SUNDAY/...
AS OF 330 AM WEDNESDAY...WILL MAINTAIN A SW FLOW AROUND BERMUDA
HIGH AROUND 10 TO 15 KTS THROUGH SATURDAY. THE WINDS WILL INCREASE
SAT NIGHT THROUGH SUNDAY AS GRADIENT TIGHTENS AS PIEDMONT TROUGH
BECOMES MORE PRONOUNCED AND NEXT COLD FRONT APPROACHES THE WESTERN
CAROLINAS BY EARLY MONDAY. SEAS WILL DIMINISH THROUGH SAT MORNING
AND THEN WILL BEGIN A RISE THROUGH SAT NIGHT AND SUNDAY POSSIBLY
REACHING ABOVE SCA THRESHOLDS BY SUN NIGHT. SEAS 3 FT OR LESS SAT
MORNING WILL REACH UP TO 3 TO 5 FT BY SUN EVENING AND NEAR 6 FT BY
EARLY MON MORNING.
-- End Changed Discussion --

&&

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

&&

$$

NEAR TERM...TRA
SHORT TERM...RGZ
LONG TERM...RGZ
AVIATION...CRM