943 
FXUS62 KILM 040304
AFDILM

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE WILMINGTON NC
1104 PM EDT FRI MAY 3 2013

.SYNOPSIS...
HIGH PRESSURE WILL EXTEND INTO THE CAROLINAS FROM THE NORTHEAST
INTO SUNDAY. AN APPROACHING LOW PRESSURE SYSTEM AND COLD FRONT
WILL BRING INCREASINGLY UNSETTLED WEATHER TO THE AREA SUNDAY AND
MONDAY. AN UPPER LOW WILL CONTINUE CHANCES FOR SHOWERS AND
THUNDERSTORMS THROUGH THE MIDDLE OF NEXT WEEK.

&&

.NEAR TERM /UNTIL 6 AM SATURDAY MORNING/...
AS OF 1035 PM FRIDAY...LATEST GFS MOS GUIDANCE IS THE CLOSER OF THE
VARIOUS MODEL MOS GUIDANCE IN REFERENCE TO PARTIALLY LINING UP
WITH CURRENT DEWPOINTS. AS A RESULT...WILL RELY MORE HEAVILY WITH
ITS OUTPUT FOR FORECASTING TONIGHTS DEWPOINTS AS WELL AS
OVERNIGHT LOWS. IN FACT...CURRENT/LATEST SFC TEMPS/DEWPOINTS ARE
ACTUALLY RUNNING EVEN SLIGHTLY LOWER THAN THE COOLER GFS MOS FOR
THE NORTHERN 2/3RD OF THE ILM CWA. THIS BASICALLY A RESULT OF
DRIER AIR FILTERING ACROSS THE AREA FROM THE NE ALONG WITH
SUBSIDENCE EXHIBITED ALOFT. HAVE BACKED DOWN ON CLOUDINESS THE
REMAINDER OF THIS EVENING AND CONTINUING INTO THE OVERNIGHT
PERIOD. RADAR MOSAIC COVERING THE EASTERN CAROLINAS AND ADJACENT
WATERS INDICATES PATCHY LIGHT RAIN/DRIZZLE JUST OFFSHORE BETWEEN
CAPE FEAR AND CAPE HATTERAS...COULD POTENTIALLY DRIFT ONSHORE
OVERNIGHT GIVEN THE TRAJECTORY IN THE LOWER LEVELS. PCPN AMOUNTS
WILL BE QUITE LIGHT WITH A TRACE TO SEVERAL ONE HUNDREDTHS
POSSIBLE. 

&&

.SHORT TERM /6 AM SATURDAY MORNING THROUGH SUNDAY NIGHT/...
AS OF 3 AM FRIDAY...OMEGA BLOCK OVER THE EASTERN CONUS WILL RESULT 
IN UNSETTLED WEATHER FOR THE WEEKEND. HIGH PRESSURE RIDGING SOUTH 
FROM NEW ENGLAND UNDER MID LEVEL RIDGING SAT WILL PRODUCE A DAY
QUITE SIMILAR TO TODAY. LOW LEVEL MOISTURE IN NORTHEAST FLOW WILL
AGAIN LEAD TO LOW CLOUDS AND DRIZZLE WITH SOME EMBEDDED LIGHT
SHOWERS. DEEP DRY AIR ALOFT AND MID LEVEL SUBSIDENCE WILL KEEP ANY
ACTIVITY CONFINED TO THE LOWEST 7K FT. SO WILL CONTINUE TO CARRY
SLIGHT CHC FOR MUCH OF SAT WITH AN INCREASE TO LOW CHC FOR SC LATE
IN THE DAY AS DEEPER MOISTURE TO THE SOUTH STARTS TO LIFT NORTH.
CLOUD COVER AND NORTHEAST FLOW WILL KEEP HIGHS BELOW CLIMO...UPPER
60S TO LOWER 70S.

SAT NIGHT INTO SUN THE SURFACE AND MID LEVEL RIDGE RETREAT NORTH.
MEANWHILE A STACKED CUTOFF OVER AR SLOWLY MOVES EAST. MID LEVEL
FLOW VEERS TO SOUTHEAST AS THE RIDGING RETREATS...ENHANCING
MOISTURE RETURN. COLD FRONT WRAPPED INTO THE STACKED LOW LIFTS
INTO THE REGION FROM THE SOUTHWEST...COINCIDENT WITH ARRIVAL OF
DEEPER MOISTURE. THE RESULT WILL BE SHOWERS DEVELOPING THEN
EXPANDING FROM SOUTHWEST TO NORTHEAST. THERE WILL BE LOBES OF
ENHANCED VORTICITY ROTATING AROUND THE SLOW MOVING CUTOFF LOW.
ALTHOUGH TIMING INDIVIDUAL LOBES IS DIFFICULT THEIR ARRIVAL SHOULD
LEAD TO PERIODIC INCREASES IN SHOWER ACTIVITY. ALTHOUGH CLOUDS
AND PRECIP WILL BE MORE PREVALENT ON SUN THE SOUTHERLY COMPONENT
TO WIND FIELD WILL RESULT IN TEMPERATURES A LITTLE WARMER ON
SUN...THOUGH STILL BELOW CLIMO. LOWS WILL BE HELD NEAR CLIMO EACH
NIGHT BY CLOUD COVER...THOUGH SOUTHERLY WINDS WILL HELP KEEP LOWS
SLIGHTLY WARMER SUN NIGHT.

&&

.LONG TERM /MONDAY THROUGH FRIDAY/...
AS OF 3 PM FRIDAY...DEEP CUTOFF LOW WILL BE MAKING ITS WAY UP
THROUGH THE SOUTHEAST MONDAY THROUGH WEDNESDAY. THE CENTER WILL BE
DIRECTLY OVERHEAD ON TUES AND WILL REACH HATTERAS BY WEDNESDAY.
BOTH THE ECMWF AND GFS WERE IN VERY GOOD AGREEMENT WITH STRENGTH
AND LOCATION OF LOW WITH THE CANADIAN MODEL MUCH FARTHER WEST. THE
SURFACE LOW ASSOCIATED WITH THIS SYSTEM WILL TRACK UP THROUGH THE
AREA AS WELL. THIS TIGHTLY WRAPPED SYSTEM WILL THROW A COLD FRONT
AROUND IT MOVING UP FROM THE SOUTHWEST WITH UNUSUALLY COOLER AIR
ADVECTING IN WITH SOUTHWESTERLY FLOW AROUND THE LOW THROUGH MON
EVENING INTO TUES. AS THIS FRONT MOVES UP THROUGH THE AREA ON
MONDAY...EXPECT A GOOD DEAL OF PCP.

THIS TIGHTLY WOUND SYSTEM WILL CONTINUE TO WRAP A FEW STRONG VORT 
LOBES AROUND THE CENTER AS IT MOVES OVER THE AREA THROUGH TUESDAY. 
H5 HEIGHTS DROP OUT ON TUES DOWN TO 560 DEM. THEREFORE EXPECT 
POTENTIAL FOR GREATER QPF AMOUNTS THROUGH TUESDAY. THE SYSTEM WILL 
CONTINUE TO WRAP AROUND MOISTURE THROUGH THURS BUT BEST LIFT AND MID 
LEVEL ENERGY WILL MOVE OFF TO THE NORTHEAST BY LATE WED. THEREFORE 
SHOULD ONLY SEE SOME LOCALIZED CONVECTION POSSIBLE ALONG SEA BREEZE 
BOUNDARY BY THURS AND FRI SHOULD BE THE DRIEST DAY. 

OVERALL EXPECT AN EXTENDED PERIOD OF UNSETTLED WEATHER WITH CLOUDS 
AND PCP AND BELOW NORMAL TEMPS. TUESDAY SHOULD BE THE COOLEST WITH 
LOW OVERHEAD...AND THEN GRADUALLY GETTING BACK TO NORMAL TEMPS BY 
THURS WITH SUNSHINE BACK IN THE FORECAST WITH A GREATER AMOUNT OF 
SUBSIDENCE AND DRIER AIR ON BACK END OF THE LOW.

&&

.AVIATION /02Z SATURDAY THROUGH WEDNESDAY/...
AS OF 00Z...VFR EXPECTED ACROSS THE AREA TONIGHT...WITH CONDITIONS 
GRADUALLY DETERIORATING TO MVFR LATE OVERNIGHT AND CONTINUING 
THROUGH MOST OF THE PERIOD ON SATURDAY. 

VFR PREVAILS THIS EVENING AS DRIER AIR HAS PUSHED IN ACROSS PORTIONS 
OF NC ALLOWING FOR SKIES TO CLEAR OUT IN SPOTS. ELSEWHERE...
SPECIALLY ACROSS OUR SC COUNTIES...CIRRUS AND ALTO CUMULUS CLOUDS
CONTINUE TO DRIFT AMONGST THE AREA. EXPECT THIS TREND TO CONTINUE
INTO THE EARLY OVERNIGHT HOURS...WITH PERSISTENT NORTHEAST WINDS
AOB 15 KTS AND PERIODS OF GUSTS. FCST SOUNDINGS AND TIME-HEIGHT
ANALYSIS IN GOOD AGREEMENT WITH REGARDS MOISTURE RETURN
OVERNIGHT...WHICH WILL ALLOW FOR LOW CIGS TO GRADUALLY MOVE
ONSHORE TOWARDS MORNING. EXPECT LOWERED CIGS TO CONTINUE INTO
SATURDAY AFTERNOON...WITH CHANCE OF DRIZZLE/ISOLATED LIGHT RAIN
SHOWERS. EAST-NORTHEAST WINDS WILL CONTINUE...WITH SUSTAINED WINDS
AOB 15 KTS AND GUSTS UP TO 25 KTS BY THE EARLY AFTERNOON HOURS.

EXTENDED OUTLOOK...SLIGHT CHANCE OF SHOWERS ESPECIALLY COASTAL 
TERMINALS THROUGH SUNDAY. IFR/MVFR EARLY SUNDAY WITH RAIN/ISOLATED 
THUNDERSTORMS DEVELOPING SUNDAY EVENING PERSISTING THROUGH MONDAY. 
MVFR/TEMPO IFR POSSIBLE. VFR/TEMPO MVFR WITH SCATTERED SHOWERS 
TUESDAY. ISOLATED SHOWERS WEDNESDAY.

&&

.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 1045 PM FRIDAY...PROGGED SFC PRESSURE PATTERN AND A
TIGHTENED SFC PRESSURE GRADIENT...WILL YIELD NE-ENE WINDS
TONIGHT...AT 20 TO 30 KT WITH FEW GUSTS UP TO GALE FORCE...
ESPECIALLY OVER THE OUTER WATERS OFF CAPE FEAR AND ROMAIN. 
FOR THE MOST PART HAVE RELIED ON THE LATEST NAM WIND FIELDS WITH
THE GFS PARTIALLY MESHED IN.

AS A SIDE NOTE...LATEST 41037 BUOY WIND OBSERVATIONS ARE RUNNING
QUITE HOT...IN REFERENCE TO ITS CURRENT GALE SUSTAINED
WINDS...WITH WIND GUSTS HAVING SURPASSED STORM FORCE. IF THIS
WERE THE CASE...CURRENT SIGNIFICANT SEAS WOULD BE WELL INTO THE
DOUBLE DIGITS ACROSS THE MAJORITY OF THE ILM COASTAL WATERS.

SIGNIFICANT SEAS RELIED ON THE LATEST SWAN GUIDANCE WHICH
ESPECIALLY ILLUSTRATES A MORE REALISTIC NEAR SHORE SIGNIFICANT
SEA HEIGHT. OVERALL...LOOKING AT A RANGE OF 4 TO 8 FT FOR THE
OVERNIGHT PERIOD...EXCEPT 9 TO POSSIBLY 10 FT ACROSS THE OUTER
WATERS OFF CAPE FEAR AND OFF WINYAH BAY. AVERAGE PERIODS WILL RUN
5.5 SECONDS...WITH DOMINANT PERIODS 7 TO 8 SECONDS.

SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/... 
AS OF 3 PM FRIDAY...GRADIENT REMAINS PINCHED SAT KEEPING NORTHEAST 
FLOW 20 TO 25 KT WITH SCA CONDITIONS CONTINUING. SEAS WILL REMAIN IN 
THE 4 TO 7 FT RANGE...MAINTAINED BY THE AFOREMENTIONED NORTHEAST 
FLOW. SURFACE RIDGE STARTS TO BREAK DOWN SAT NIGHT WITH WINDS 
VEERING TO SOUTHEAST SUN AS LOW PRESSURE AND ASSOCIATED COLD FRONT 
APPROACHES FROM THE SOUTHWEST. GRADIENT SLOWLY WEAKENS SUN AND
SUN NIGHT WITH EAST TO SOUTHEAST WINDS DECREASING FROM 15 TO 20 KT
TO 10 TO 15 KT BY THE END OF THE PERIOD. SEAS SLOWLY DECREASE SUN
INTO SUN NIGHT...DROPPING TO 3 TO 6 FT BY THE END OF THE PERIOD.

LONG TERM /MONDAY THROUGH WEDNESDAY/...
AS OF 3 PM FRIDAY...TIGHTLY WOUND LOW PRESSURE SYSTEM WILL TRACK
UP THROUGH THE SOUTHEAST MONDAY THROUGH WEDNESDAY. A COLD FRONT
WILL WRAP AROUND THIS SYSTEM MOVING THROUGH THE WATERS MONDAY
MORNING FROM SOUTHWEST TO NORTHEAST. THIS WILL PRODUCE A WINDS
SHIFT FROM MORE EASTERLY TO SOUTHWEST. THE TIGHTENED GRADIENT FLOW
WILL RELAX WITH WINDS GENERALLY S-SW 10 KTS OR LESS. SEAS WILL
DROP BELOW SCA THRESHOLDS IN THE OUTER WATERS AND WILL RUN AROUND
3 TO 5 FT BUT WILL CONTINUE TO DROP THROUGH LATE MONDAY INTO TUES
DOWN TO 2 TO 4 FT IN LIGHTER SOUTHERLY FLOW. OVERALL WINDS WILL
REMAIN SW TO W THROUGH THE PERIOD WITH SEAS ON A SLOW DOWNWARD
TREND.

&&

.ILM WATCHES/WARNINGS/ADVISORIES...
SC...NONE.
NC...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 6 PM EDT SUNDAY FOR AMZ250-252-254-
     256.

&&

$$
SYNOPSIS...III
NEAR TERM...DCH
SHORT TERM...III
LONG TERM...RGZ
AVIATION...SGL