639 
FXUS62 KILM 062341
AFDILM

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE WILMINGTON NC
741 PM EDT SAT SEP 6 2014

.SYNOPSIS...
WAVES OF SHOWERS AND A FEW THUNDERSTORMS WITH HEAVY RAINFALL WILL
CONTINUE THROUGH MONDAY AS LOW PRESSURE ALONG THE GEORGIA COAST
LINKS UP WITH A COLD FRONT DIPPING IN FROM THE NORTH. AS THE LOW
EXITS MONDAY NIGHT...A GRADUAL AND WARMING DRYING TREND SHOULD
DEVELOP TUESDAY AND PERSIST INTO LATE NEXT WEEK.

&&

.NEAR TERM /UNTIL 6 AM SUNDAY MORNING/...
AS OF 700 PM SATURDAY...DID NOT THINK THAT THE ILM CWA WOULD BE
NEARLY PCPN-FREE AT THIS TIME. KLTX 88D IS OBS AND TRENDS CONFIRM
THIS CONVECTION FREE TIME FOR THE MOMENT. DETAILED HOURLY MODEL
MODEL DATA HAS SOMEWHAT CAUGHT UP...IE. THE HRRR MODEL...AND IT
SAYS THAT THE REMAINDER OF THIS EVENING LOOKS TO REMAIN PCPN
FREE...ESPECIALLY INLAND. HOWEVER...THE HRRR SEEMS OVERDONE WITH
ONSHORE MOVEMENT OF PCPN THIS EVENING ESPECIALLY WHEN COMPARING
THE LATEST HRRR REFLECTIVITY WITH CURRENT KLTX 88D RADAR DATA.
AS A RESULT...HAVE LOWERED POPS BY UP TO A SEVERAL CATEGORIES FOR
THE REMAINDER OF THIS EVENING. THE HRRR AND ESPECIALLY THE LATEST
NAM CONTINUE WITH INCREASING DEVELOPMENT OF NOCTURNAL ATL
CONVECTION ALONG OUR ADJACENT COASTAL AND OFFSHORE WATERS AFTER
MIDNIGHT...AND THEIR ONSHORE MOVEMENT DURING THE SUNDAY PRE-DAWN
HRS. WILL RAMP POPS BACK UP ACROSS THE FA...MAINLY ACROSS THE
COASTAL COUNTIES WITH A SLOWER INCREASING POP TREND LEADING UP TO
THE I-95 CORRIDOR. HAVE ALSO DECREASED CLOUDINESS ACROSS THE FA
FOR THIS EVENING. HAVE NOT INTRODUCED FOG AT THE MOMENT BUT IF THE
FA EXPERIENCES AN EXTENDED PERIOD OF MOSTLY CLEAR SKIES THIS
EVENING AND/OR OVERNIGHT...FOG MAY BECOME AN ISSUE. HAVE TWEAKED
VERY LITTLE WITH TONIGHTS LOWS...LOOK AOK EVEN WITH A MOSTLY CLEAR
SKIES AT TIMES. TROPICAL AIR MASS REMAINS IN PLACE...WITH SFC 
DEWPOINTS REMAINING IN THE LOW TO MID 70S.

PREVIOUS DISCUSSION................................................
AS OF 2 PM SATURDAY...ONGOING DIURNAL CONVECTION INLAND WILL LINGER 
INTO THE EVENING HOURS BEFORE THE LOSS OF HEATING BRINGS ABOUT ITS 
DEMISE. COVERAGE WILL VARY FROM LOW CHANCE TO LIKELY AT TIMES
WITH STORMS HAVING THE ABILITY TO DROP SIGNIFICANT RAINFALL IN A
SHORT PERIOD OF TIME. HOWEVER STORM MOVEMENT IS FAST ENOUGH TO
LIMIT FLOODING POTENTIAL TO TRAINING STORMS. CLOSER TO THE COAST
LINGERING DEBRIS CLOUD FROM THIS MORNINGS CONVECTION HAS SO FAR
INHIBITED HEATING...THUS LIMITING INSTABILITY AND STORM
DEVELOPMENT...ESPECIALLY ACROSS COASTAL NC. ALTHOUGH CLOUD COVER
WILL CONTINUE TO DIMINISH ALONG THE COAST THIS AFTERNOON IT LOOKS
LIKE THERE MAY NOT BE ENOUGH TIME TO GENERATE ENOUGH INSTABILITY
FOR ANYTHING MORE THAN ISOLATED SHOWERS. HAVE BACKED OFF ON POP
FOR THE AFTERNOON HOURS ALONG THE COAST...THOUGH AN ISOLATED
SHOWER OR THUNDERSTORM WILL STILL BE POSSIBLE.

DEEP MOISTURE PLUME WILL SPREAD NORTH INTO THE REGION TONIGHT
PUSHING PRECIPITABLE WATER VALUES OVER 2 INCHES. AT THE SAME TIME
LOW LEVEL JETTING AHEAD OF THE SLOWLY ADVANCING COLD FRONT
INCREASES TO 20 TO 25 KT. LOW LEVEL CONVERGENCE ALONG THE COASTAL
TROUGH COMBINED WITH THE NOCTURNAL JETTING AND THE DEEP MOISTURE
SHOULD PRODUCE OFFSHORE CONVECTION...SOME OF WHICH WILL LIKELY
MOVE ONSHORE OVERNIGHT. NOT CONFIDENT SHOWERS AND THUNDERSTORMS
WILL MOVE FAR INLAND...GIVEN THE LOCATION OF THE TROUGH NEAR THE
COAST AND LIMITED INSTABILITY IN THESE AREAS. WHILE IT IS WEAK FOR
THE FIRST TIME IN SEVERAL DAYS THERE WILL BE SOME UPPER LEVEL
SUPPORT AS FLOW ALOFT BECOMES WEAKLY DIVERGENT. THIS COULD AID
ONGOING STORMS BUT BY ITSELF WOULD PROBABLY NOT BE STRONG ENOUGH
TO GENERATE CONVECTION. 

HEAVY RAIN WILL BE POSSIBLE WITH ANY STORMS THAT DO DEVELOP GIVEN
THE DEEP MOISTURE AND FREEZING LEVEL OF 15.6K FT OVERNIGHT. STORM
MOTIONS WILL REMAIN ABOVE 10 KT SO STORM MOTION SHOULD NOT
CONTRIBUTE TO FLOODING BUT TRAINING OR BACK BUILDING STORMS WOULD
HAVE POTENTIAL TO CAUSE LOCALIZED FLOODING GIVEN THE EXPECTED HIGH
PRECIPITATION RATES.

CLOUD COVER AND MOISTURE WILL HELP KEEP LOWS IN THE 70S...BUT ALONG 
THE COAST RAINFALL WILL KEEP TEMPS COOLER. COAST SHOULD STILL END
UP WARMEST BUT BY A COUPLE DEGREES AT MOST.

&&

.SHORT TERM /6 AM SUNDAY MORNING THROUGH MONDAY NIGHT/...
AS OF 300 PM SATURDAY...A NON-FRONTAL LOW OVER EASTERN GEORGIA AND
SOUTHERNMOST SOUTH CAROLINA WILL HELP ADVECT IN A RICH TROPICAL
AIRMASS INLAND WITH PRECIPITABLE WATER VALUES 2.0 TO 2.3 INCHES.
OFFSHORE SHOWERS AND T-STORMS SHOULD SWEEP ONSHORE SUNDAY MORNING
ACROSS THE GRAND STRAND AND CAPE FEAR REGION...WITH DAYTIME
HEATING NUDGING THE BEST COVERAGE OF SHOWERS & STORMS INLAND
DURING THE AFTERNOON HOURS. A SYNOPTIC COLD FRONT OVER THE CENTRAL
CAROLINAS WILL SLIP SOUTHEASTWARD INTO THE COASTAL PLAIN SUNDAY
AFTERNOON...INTERCEPTING THE FEED OF TROPICAL MOISTURE AND STALLING
ABOUT HALFWAY BETWEEN I-95 AND THE COAST. THIS IS A GOOD SETUP FOR
SHOWERY WEATHER WITH LOCALIZED HEAVY RAIN...AND FORECAST POPS
SUNDAY RANGE FROM 60-80 PERCENT.

THE SOUTH CAROLINA LOW IS BEING SUSTAINED AT LEAST IN PART BY
CONVECTIVE PROCESSES. THE CYCLONIC SWIRL EXTENDS UP THROUGH 500 MB
WITH A RIDGE PRESENT UP AT 200/300 MB. WHILE THE ODDS FAVOR THIS
SYSTEM NOT INTENSIFYING INTO A NAMED TROPICAL CYCLONE (THE CENTER
IS EXPECTED TO REMAIN INLAND) IT MAY BRING WEATHER REMINISCENT TO
THAT OF A WEAK TROPICAL DEPRESSION. WAVES OF SHOWERS...SOME
HEAVY...WILL CONTINUE TO SWEEP ONSHORE SUNDAY NIGHT INTO MONDAY.
AS THE COLD FRONT REMAINS STALLED ACROSS THE COASTAL PLAIN
MONDAY...THE LOW SHOULD LINK UP WITH THIS BOUNDARY AND BEGIN TO
MOVE NORTHEASTWARD...FINALLY REACHING SOUTHEASTERN NORTH CAROLINA
MONDAY NIGHT AND ACCELERATING OUT TO THE NORTHEAST AFTER MIDNIGHT.
THIS SHOULD SPELL AN END TO THE SHOWERY WEATHER AND SHOULD PUSH
THE FRONT OFF THE COAST.

FROM AN AREAL STANDPOINT WE ARE EXPECTING AS MUCH AS 2.5 INCHES OF
RAIN ALONG THE COAST TONIGHT THROUGH MONDAY NIGHT WITH 1.0 TO 1.7
INCHES NEAR/WEST OF I-95. ISOLATED AREAS COULD REALISTICALLY PICK
UP 5 TO 7 INCHES. THE 12Z NAM WAS AN OUTLIER VERSUS THE GFS/ECMWF
WITH REGARDS TO HOW MUCH THE SURFACE LOW AND ASSOCIATED
WIND/ADVECTION FIELDS INTENSIFY...BUT CANNOT BE RULED OUT. SHOULD
CONFIDENCE GROW THAT EXCESSIVE RAINFALL WILL OCCUR A FLOOD WATCH
MAY BE NEEDED FOR PORTIONS OF COASTAL SOUTH AND NORTH CAROLINA.

DIURNAL TEMPERATURE RANGES WILL BE CONSTRICTED BY ALL THE CLOUDS
AND PRECIPITATION...PARTICULARLY ON MONDAY WHEN A SOLID OVERCAST
MAY PERSIST FOR A GOOD PORTION OF THE DAY WEST OF THE STALLED
FRONT. MOS CONSENSUS TEMPERATURES LOOK REASONABLE -- EXCEPT FOR
HIGHS MONDAY WHERE I HAVE TRIMMED UP TO FIVE DEGREES OFF WEST OF
THE FRONT.

&&

.LONG TERM /TUESDAY THROUGH SATURDAY/...
AS OF 300 PM SATURDAY...LOW PRESSURE WILL MOVE UP THE CAROLINA
COAST ALONG A LINGERING COLD FRONT AS WEAK HIGH PRESSURE BUILDS IN
BEHIND IT THROUGH TUESDAY. ANY LINGERING CLOUDS OR SHOWERS TUES
WILL DIMINISH THROUGH LATE TUES INTO WED AS DRY AIR MOVES IN ABOVE
H85. PCP WATER VALUES UP CLOSE TO 2 INCHES EARLY TUES WILL DROP
DOWN TO 1.5 INCHES BY TUES EVE AND EVEN FURTHER BY WED MORNING.
WEAK HIGH PRESSURE WILL REMAIN AT THE SURFACE WHILE RIDGE IN THE
MID TO UPPER LEVELS BUILDS BACK UP THROUGH THE CAROLINAS THROUGH
MID WEEK WITH PLENTY OF DRY AIR AND SUBSIDENCE ALOFT. MAY INCLUDE
A VERY LOW END CHC OF SHWRS ON WED AND THURS BUT OVERALL EXPECT
PLENTY OF SUNSHINE WITH SOME LOCALIZED CU DEVELOPMENT AND POSSIBLY
A STRAY SHWR. BY LATE THURS INTO FRI CHC OF PCP WILL INCREASE AS
RIDGE ALOFT GETS SUPPRESSED FARTHER SOUTH AS A SHORTWAVE BEGINS TO
DIG DOWN AS IT RIDES ACROSS THE GREAT LAKES. THIS SHORTWAVE WILL
PUSH A COLD FRONT INTO THE CAROLINAS BY FRI INTO SATURDAY WITH
MORE WIDESPREAD SHWR AND TSTMS EXPECTED HEADING INTO THE WEEKEND.

TEMPS NEAR NORMAL ON TUES IN LINGERING CLOUDS AND SHWRS WILL WARM UP 
AGAIN THROUGH MID WEEK AS H5 HEIGHTS RISE WITH BUILDING RIDGE. 
EXPECT TEMPS IN THE MID 80S ON TUES WILL BE BACK UP AROUND 90 OR SO 
BY THURS AND FRI. BY SATURDAY CLOUDS AND SHWRS ASSOCIATED WITH COLD 
FRONT WILL KEEP TEMPS IN THE 80S.

&&

.AVIATION /00Z SUNDAY THROUGH THURSDAY/...
AS OF 00Z...THE RADAR IS QUIET THIS EVENING SO WE CAN EXPECT A LULL 
IN PCPN EARLY TONIGHT. A WEAK SFC LOW NEAR THE GA/SC COAST WILL 
SLOWLY MOVE NORTHEAST OVERNIGHT...AND THE HRRR INDICATES MORE SHOWER 
ACTIVITY WILL SPREAD UP THE COAST AFTER 06Z SUN. THIS COULD RESULT 
IN TEMPO MVFR CIGS/VSBYS AT THE COASTAL TERMS EARLY SUN MORNING. 
HAVE NOT INCLUDED VCSH FOR KFLO/KLBT AS THE HI-RES GUIDANCE AND SREF 
PROBS INDICATE PCPN WILL MAINLY BE CONFINED TO THE COAST. BUT THE 
RELATIVE LACK OF CLOUD COVER INLAND COULD RESULT IN IFR CIGS AND/OR 
VSBYS AROUND DAYBREAK AT KFLO/KLBT. SINCE CONFIDENCE IS STILL LOW 
ATTM...WILL INCLUDE MVFR VSBYS AND SCT 500 FT STRATUS AND REEVALUATE 
WITH THE NEXT ISSUANCE. EXPECT WIDESPREAD SHOWERS DURING THE DAY SUN 
AS TROPICAL MOISTURE STREAMS ONSHORE AND A COLD FRONT ENTERS OUR 
CWA. THERE WILL LIKELY BE SOME MVFR/IFR VSBYS IN LOCALLY HEAVIER 
SHOWERS...BUT FOR NOW WILL CARRY 6SM SHRA AND MVFR CIGS FOR ALL 
TERMINALS THROUGH THE DAY.

EXTENDED OUTLOOK...SHOWERS WITH PERIODS OF MVFR CIGS AND MVFR/IFR 
VSBYS THROUGH MONDAY. VFR TUESDAY THROUGH THURSDAY.

&&

.MARINE...
NEAR TERM /THROUGH TONIGHT/...
AS OF 715 PM SATURDAY...LATEST BUOY AND PIER SIGNIFICANT SEAS AND
WINDS OBS FROM WITHIN AND NEARBY LOCATIONS ACROSS THE ILM CWA 
INDICATE A RATHER SOLID SSE-SSW WIND AROUND 15 KT WITH SIG. SEAS
ALREADY IN THE 3 TO 4 FT RANGE. A FEW SAMPLED BUOYS AND PIERS
INCLUDE 41108...41110...41036-7 AND 8...MROS1...JMPN7 AND OCPN7.
THE SFC PG IS PROGGED TO EVEN FURTHER TIGHTEN LATER TONIGHT WHICH
MAY REQUIRE AN ADDITIONAL CWF UPDATE LATER THIS EVENING FOR THE
POSSIBLE ISSUANCE OF A SCEC....IE. WINDS SSE-SSW 10-20 KT AND SIG.
SEAS 3 TO 5 FT. WILL CONTINUE TO CLOSELY MONITOR.

PREVIOUS DISCUSSION...............................................
AS OF 2 PM SATURDAY...ALTHOUGH GRADIENT WILL CHANGE LITTLE
OVERNIGHT THE STRENGTHENING LOW LEVEL JET WILL RESULT IN SLIGHTLY
HIGHER WIND SPEEDS THAN PREVIOUS NIGHTS. SOUTH TO SOUTHWEST FLOW
WILL HANG IN THE 10 TO 15 KT RANGE WITH POTENTIAL FOR THE
OCCASIONAL GUST EXCEEDING 15 KT. SEAS WILL CONTINUE 2 TO 3 FT
OVERNIGHT BUT WITH SOME ISOLATED 4 FT THROWN IN DUE TO PROLONGED
SOUTHERLY FETCH AND THE SLIGHT INCREASE IN SPEEDS.

SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/...
AS OF 300 PM SATURDAY...A COLD FRONT OVER THE CENTRAL CAROLINAS
SUNDAY MORNING WILL SAG INTO THE COASTAL PLAIN BY AFTERNOON...
STALLING AS IT ENCOUNTERS AN AREA OF LOW PRESSURE OVER
SOUTHERNMOST SOUTH CAROLINA. THIS LOW IS BEING MAINTAINED (AT
LEAST IN PART) BY SHOWER AND THUNDERSTORM ACTIVITY ONGOING AROUND
IT. WHILE THE ODDS DO NOT FAVOR THE DEVELOPMENT OF A NAMED
TROPICAL SYSTEM...THIS SITUATION WILL HAVE SOME PARALLELS TO WHAT
WE MIGHT EXPERIENCE DURING A WEAK TROPICAL DEPRESSION. THE LOW
OVER SOUTH CAROLINA WILL LIFT SLOWLY NORTHEASTWARD ALONG THE FRONT
SUNDAY NIGHT AND MONDAY...REACHING SOUTHEASTERN NORTH CAROLINA
MONDAY NIGHT. THIS MEANS WE'LL HAVE AN EXTENDED PERIOD OF HEAVY
SHOWERS AND MODERATE SOUTH WINDS SUNDAY THROUGH MONDAY EVENING...
WITH WINDS VEERING MORE WESTERLY LATE MONDAY NIGHT AS THE LOW
ACCELERATES NORTHEASTWARD THROUGH EASTERN NORTH CAROLINA.

AT THIS TIME THE HIGHEST WINDS WE ARE EXPECTING ARE 15-20 KNOTS
WITH GUSTS IN THE LOWER 20S. THIS IS OF COURSE VERY DEPENDENT ON
HOW MUCH (IF ANY) STRENGTHENING OCCURS OF THE SYSTEM BEYOND THE
WEAK FRONTAL LOW NOW EXPECTED. ASSUMING THESE WINDS PAN OUT SEAS
SHOULD BUILD TO 4-5 FEET AWAY FROM SHORE...HIGHEST SUNDAY NIGHT
INTO MONDAY MORNING ACROSS THE WATERS SOUTH OF CAPE FEAR.

LONG TERM /TUESDAY THROUGH THURSDAY/...
AS OF 300 PM SATURDAY...LOW PRESSURE ALONG LINGERING FRONT ALONG THE 
CAROLINA COAST EARLY TUES WILL LIFT OFF TO THE NORTHEAST THROUGH THE 
DAY. THIS MAY CAUSE VARIABLE WINDS OVER THE COASTAL WATERS ON TUES 
BUT OVERALL SHOULD SEE SW-W WINDS BECOMING NORTHERLY AND LIGHTEN 
THROUGH EARLY WED. WEAK HIGH PRESSURE OVER THE WATERS WILL MAINTAIN 
LIGHT AND VARIABLE WINDS COMING AROUND TO THE SOUTH BY THURS BUT 
REMAINING 10 KTS OR LESS. THE OFF SHORE WINDS WILL KNOCK SEAS DOWN 
THROUGH TUES FROM 2 TO 4 FT EARLY DOWN TO 3 FT OR LESS TUES NIGHT 
THROUGH THURS.

&&

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

&&

$$
SYNOPSIS...TRA
NEAR TERM...DCH/III
SHORT TERM...TRA
LONG TERM...RGZ
AVIATION...BJR