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-- Discussion containing changed information from previous version are highlighted. --
000
FXUS62 KILM 210722
AFDILM

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE WILMINGTON NC
322 AM EDT TUE MAY 21 2013

.SYNOPSIS...
-- Changed Discussion --
WEAK UPPER LEVEL DISTURBANCE AND HIGH PRESSURE OFFSHORE WILL
CONTINUE THE POTENTIAL FOR SHOWERS AND THUNDERSTORMS TODAY. DRIER
AND WARMER WEATHER IS EXPECTED FOR MID-WEEK. A COLD FRONT WILL
APPROACH...AND CROSS THE REGION EARLY FRIDAY. COOLER AND DRIER
WEATHER WILL DEVELOP FOR THE WEEKEND.
-- End Changed Discussion --

&&

.NEAR TERM /THROUGH TONIGHT/...
-- Changed Discussion --
AS OF 300 AM TUESDAY...THE WEAK UPPER LEVEL DISTURBANCE THAT BEGAN
THIS RECENT WET PERIOD SEVERAL DAYS AGO HAS DEGENERATED INTO A
500-TO-700 MB SHEAR AXIS. WIND SPEEDS SURROUNDING THE UPPER FEATURE
ARE TOO WEAK AT THIS POINT TO SUPPORT DYNAMIC LIFT...BUT RICH LOW
AND MID LEVEL MOISTURE REMAINS IN PLACE ACROSS THE EASTERN CAROLINAS
WITH PRECIPITABLE WATER VALUES AROUND 1.7 INCHES. THE LACK OF ANY
CONVECTIVE CAP...DEEP-LAYER ENVIRONMENTAL LAPSE RATES SLIGHTLY
STEEPER THAN THE MOIST ADIABATIC LAPSE RATE...AND THIS AFTERNOON`S
SEABREEZE BOUNDARY SHOULD HELP PRODUCE ANOTHER ROUND OF SCATTERED
SHOWERS AND THUNDERSTORMS. SLOW STORM MOTION AND A DEEP REGION
(NEARLY 10000 FEET DEEP) WHERE EFFICIENT WARM-CLOUD COALESCENCE
PROCESSES WILL DOMINATE SHOULD ALLOW HEAVY RAINFALL TO OCCUR. HIGHS
THIS AFTERNOON SHOULD REACH THE LOWER 80S FOR MOST AREAS AWAY FROM
THE BEACHES.

SHOWER ACTIVITY SHOULD END QUICKLY THIS EVENING...ALTHOUGH PLENTY OF
RESIDUAL MOISTURE SHOULD ENSURE SKIES REMAIN PARTLY CLOUDY
OVERNIGHT. MODELS HINT AT SOME NOCTURNAL CONVECTIVE DEVELOPMENT OVER
THE OCEAN WHICH MAY MAKE A RUN AT CAPE FEAR LATE TONIGHT. WITH A
LITTLE LESS CLOUD COVER THAN WE HAVE SEEN OVER THE PAST FEW
NIGHTS...LOWS SHOULD DROP INTO THE MID 60S INLAND WITH UPPER 60S AT
THE COAST.
-- End Changed Discussion --

&&

.SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/...
-- Changed Discussion --
AS OF 300 AM TUESDAY...MID LEVEL RIDGING AND BERMUDA HIGH PRESSURE
PERSIST ON WEDNESDAY BEFORE PATTERN CHANGE FINALLY OCCURS LATE IN
THE PERIOD. WHILE TEMPS BOTH DAYS WILL CONTINUE TO BE SEVERAL
DEGREES ABOVE CLIMO...MID AND UPPER 80S...WEDNESDAY IS LIKELY TO BE
A DRIER DAY WITH ONLY ISOLATED CONVECTION DUE TO SUBSIDENCE/CAPPING
BENEATH THE 5H RIDGE. 5H RIDGE...AS QUOTED BY THE PREVIOUS
FORECASTER...BREAKS DOWN SURPRISINGLY QUICKLY...THURSDAY AS LONGWAVE
TROUGH EXITS THE MIDWEST AND PUSHES EAST. THIS IN ITSELF WILL LEAD
TO INCREASED CONVECTION CHANCES THURSDAY DUE TO COOLER TEMPS ALOFT
STEEPENING LAPSE RATES. AN ADDITIONAL FACTOR TO CONVECTION THURSDAY
WILL BE THE APPROACH OF A COLD FRONT WHICH IS NOW PROGGED TO CROSS
THE AREA OVERNIGHT THURSDAY NIGHT. WITH GOOD THETA-E ADVECTION AHEAD
OF THIS BOUNDARY...WILL BUMP POP TO HIGH CHC EVEN THURSDAY NIGHT FOR
SHOWERS/TSTMS...WITH DRYING OCCURRING IN THE COLUMN AT THE VERY END
OF THE PERIOD.

MINS WED NIGHT WILL BE WELL ABOVE NORMAL...UPPER 60S TO NEAR 70.
SEVERAL DEGREES COOLER THURSDAY NIGHT AS THE FROPA OCCURS...FALLING
INTO THE LOW/MID 60S.
-- End Changed Discussion --

&&

.LONG TERM /FRIDAY THROUGH MONDAY/...
-- Changed Discussion --
AS OF 300 AM TUESDAY...BEAUTIFUL LATE MAY WEATHER EXPECTED FOR THE
EXTENDED AS DRIER BUT STILL SEASONABLE AIR DEVELOPS ACROSS THE
CAROLINAS. COLD FRONT WILL BE JUST EXITING OFFSHORE AT THE START OF
THE PERIOD...WITH MUCH DRIER AIR FLOODING IN BEHIND IT AS A HIGH
PRESSURE BUILDS DOWN FROM THE NW. WHILE A FEW SHOWERS MAY LINGER
VERY EARLY FRIDAY...WILL QUICKLY RAMP POP DOWN TO SILENT FRIDAY
THROUGH MONDAY AS HIGH PRESSURE BUILDS ACROSS THE AREA HELPING PWATS
DROP TO WELL BELOW ONE INCH. EVEN WITH HIGH PRESSURE BUILDING DOWN
FROM THE NW...THE OVERALL AIR MASS CHANGE WILL BE ONE TO MUCH DRIER
CONDITIONS AS OPPOSED TO MUCH COOLER...WITH TEMPS FALLING TO JUST A
FEW DEGREES BELOW CLIMO...AND A NEAR PERFECT LATE-SPRING WKND
APPEARS TO BE IN STORE FOR THIS AREA.
-- End Changed Discussion --

&&

.AVIATION /07Z TUESDAY THROUGH SATURDAY/...
AS OF 06Z...PLENTIFUL LOW-LEVEL MOISTURE HAS LED TO DEVELOPMENT OF
IFR STRATUS CEILINGS INLAND WHICH MAY CONTINUE THROUGH DAYBREAK. THE
ONLY POTENTIAL TO SCOUR OUT THESE LOW CIGS EARLIER WILL BE IF
CONVECTIVE SHOWERS OR T-STORMS CAN DEVELOP ACROSS THE SC PEE DEE
REGION AS SHOWN ON THE LATEST SEVERAL RUNS OF THE HRRR MODEL. THIS
COULD LEAD TO ENOUGH DISTURBANCE OF THE STABLE LOW-LEVEL INVERSION
TO LIFT CEILINGS AT KFLO TEMPORARILY INTO THE VFR RANGE SHORTLY
BEFORE DAYBREAK. ALONG THE COAST VFR CONDITIONS SHOULD PREVAIL
THROUGH DAYBREAK WITH THE POSSIBLE EXCEPTION OF SCATTERED SHOWERS
ADVECTING ONSHORE OFF THE ATLANTIC OCEAN...MAINLY AFTER 09Z...WITH
ACCOMPANYING MVFR CIGS.

AFTER DAYBREAK A TYPICAL SUMMER AIRMASS WILL YIELD SCATTERED SHOWERS
AND THUNDERSTORMS DURING THE HEAT OF THE DAY. PREVAILING SOUTH WINDS
SHOULD SWEEP MOST OF THE ACTIVITY AWAY FROM THE COAST BY
MID-AFTERNOON WITH FLO/LBT SEEING THE BEST POTENTIAL OF VSBY
RESTRICTIONS IN SHOWERS OR STORMS.

EXTENDED OUTLOOK...SCATTERED SHOWERS/TSTMS WITH TEMPO MVFR ON
TUESDAY. CHANCE OF SHOWERS THURSDAY THROUGH EARLY FRIDAY. OTHERWISE
VFR.

&&

.MARINE...
-- Changed Discussion --
NEAR TERM /THROUGH TONIGHT/...
AS OF 300 AM TUESDAY...THERE HAS BEEN AMAZINGLY LITTLE CHANGE IN THE
OVERALL SYNOPTIC WEATHER PATTERN OVER THE PAST 24 HOURS. HIGH
PRESSURE HAS DROPPED SOUTH TO NEAR BERMUDA WHILE LOW PRESSURE IN THE
NORTHERN PLAINS IS STILL SITTING OVER EASTERN SOUTH DAKOTA. THIS
WILL ENSURE A SOUTH WIND AT 10-15 KNOTS CONTINUES TODAY THROUGH
TONIGHT. SCATTERED SHOWERS AND POSSIBLY A FEW THUNDERSTORMS WILL BE
MOST NUMEROUS THIS MORNING...WITH SUBSIDENCE BEHIND THE SEABREEZE
CLEARING OUT MOST OF THIS ACTIVITY FROM THE COASTAL WATERS THIS
AFTERNOON. SEAS CURRENTLY RANGE FROM 3-4 FT ON BUOYS IN THE CAPE
FEAR VICINITY...IN A COMBINATION OF 10 SECOND EASTERLY SWELL AND A 6
SECOND SOUTHERLY WIND WAVE.

SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/...
AS OF 300 AM TUESDAY...BERMUDA HIGH PRESSURE REMAINS IN PLACE
WEDNESDAY BEFORE GRADUALLY PUSHING AWAY THURSDAY THANKS TO A COLD
FRONT WHICH WILL CROSS THE WATERS AT THE VERY END OF THE PERIOD.
WITH BERMUDA HIGH IN PLACE WED...RETURN FLOW CREATES S/SW WINDS OF
10-15 KTS...CREATING SEAS OF 2-4 FT WITH A 6 SEC SOUTHERLY WIND WAVE
DOMINANT IN THE WAVE SPECTRUM. BY THURSDAY...WINDS BEGIN TO VEER
SLOWLY AS COLD FRONT APPROACHES FROM THE WEST. WINDS WILL REMAIN
10-15 KTS...BUT VEER TO THE SW THU AFTN AND THEN FINALLY TO THE WEST
LATE THURSDAY NIGHT WITH THE ACTUAL FROPA. SEAS WILL BRIEFLY RISE TO
3-5 FT DURING THURSDAY...BEFORE FALLING BACK TO 2-4 FT AT THE END OF
THE PERIOD.

LONG TERM /FRIDAY THROUGH SATURDAY/...
AS OF 300 AM TUESDAY...COLD FRONT EXITING OFFSHORE AT THE START OF
THE PERIOD...WITH HIGH PRESSURE BUILDING DOWN FROM THE NW INTO
SATURDAY. WINDS WILL VEER SIGNIFICANTLY DURING THE PERIOD...FROM
WEST AROUND 10 KTS FRIDAY MORNING...TO NORTH AT 15 KTS FRIDAY
NIGHT...THEN NE AT 15-20 KTS ON SATURDAY THANKS TO A PINCHED
PRESSURE GRADIENT JUST OFFSHORE. SEAS WILL BE ENTIRELY WIND-WAVE
DOMINATED DURING THE EXTENDED...BUILDING FROM 2-4 FT FRIDAY...TO 3-5
FT ON SATURDAY WITH A NORTHERLY CHOP BECOMING PREDOMINANT.
-- End Changed Discussion --

&&

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

&&

$$
SYNOPSIS...JDW
NEAR TERM...TRA
SHORT TERM...JDW
LONG TERM...JDW
AVIATION...TRA
MARINE...TRA/JDW