Area Forecast Discussion
Issued by NWS Wilmington, NC

Current Version | Previous Version | Graphics & Text | Print | Product List | Glossary Off
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50
-- Highlight Changed Discussion --
-- Discussion containing changed information from previous version are highlighted. --
000 FXUS62 KILM 280017 AFDILM AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE WILMINGTON NC 817 PM EDT SAT SEP 27 2014 .SYNOPSIS... HIGH PRESSURE BUILDING FROM THE NORTH WILL BRING A DRYING TREND THROUGH THE WEEKEND AS A COASTAL TROUGH WEAKENS OFFSHORE. A WET FORECAST IS SHAPING UP FOR EARLY NEXT WEEK AS LOW PRESSURE MOVES ACROSS THE SOUTHEAST. HIGH PRESSURE WILL RE-BUILD FROM THE NORTH THROUGH MID WEEK...WITH A COLD FRONT MOVING IN AT THE END OF THE WEEK. && .NEAR TERM /UNTIL 6 AM SUNDAY MORNING/...
-- Changed Discussion --
AS OF 730 PM SATURDAY...LATEST LOCAL KLTX AND 88D MOSAIC KEEPS THE MAIN PCPN SHIELD SOUTH OF CAPE FEAR. LATEST HRRR MODEL KEEPS ANY ONSHORE MOVEMENT OF THE PCPN ACROSS THE ILM SC COUNTIES. AS A RESULT...HAVE ADJUSTED POPS KEEPING THEM AT LOW CHANCE TO AFFECT MAINLY THOSE SC COUNTIES OVERNIGHT. CLOUDINESS HAS BEEN ADJUSTED UPWARDS DUE TO ONGOING VARIABLY SKY CONDITIONS AND THE TRAPPED MOISTURE BELOW 700 MB AS ADVERTISED BY VARIOUS MODEL TIME HEIGHT DISPLAYS ACROSS THE FA. MIN TEMPS SLIGHTLY TWEAKED...TOWARDS THE UPWARD SIDE DUE TO MORE CLOUDINESS AND THREAT OF PCPN. PREVIOUS DISCUSSION............................................... AS OF 3 PM SATURDAY...HIGH PRESSURE CONTINUES TO WEDGE DOWN THE COAST THIS AFTN...INTERACTING WITH A COASTAL TROUGH THAT SEEMS TO BE EVER-PRESENT JUST OFFSHORE. WEAK LOW PRESSURE OFF THE CHARLESTON, SC COAST WILL CONTINUE TO DROP WEAKLY TO THE SOUTH TONIGHT AS HIGH PRESSURE BECOMES MORE DOMINANT. AREAS OF SHOWERS ALONG THE COASTAL TROUGH HAVE BEEN TRYING TO PUSH ONSHORE TODAY...DRIVEN BY THE E/NE FLOW BETWEEN THE SURFACE WEDGE AND COASTAL TROUGH. THE MID-LEVELS OF THE COLUMN...THOSE ABOVE 750MB...ARE VERY DRY...AND THE CONTINENTAL AIR MASS IS DRIER THAN THAT OFFSHORE. THIS IS PRECLUDING MOST OF THE SHOWER ACTIVITY FROM MAKING IT ONSHORE...BUT CANNOT RULE OUT SOME ISOLATED LIGHT SHOWERS THROUGH TONIGHT...FOCUSED ALONG THE COAST...WITH BEST CHANCE ALONG THE GRAND STRAND AND DOWN TOWARDS THE SOUTH SANTEE RIVER. THE NAM FORECAST PROFILES ARE HANDLING THE CLOUD COVER BEST TODAY...SO USING THIS AS A GUIDE EXPECT LOW LEVEL CLOUDINESS TO PERSIST INTO TONIGHT. AS THE HIGH BECOMES MORE STRONGLY ENTRENCHED LOCALLY CLOUD COVER WILL WANE...BUT EXPECT ONCE AGAIN QUITE A BIT OF STRATUS AROUND TONIGHT. THIS WILL LIMIT OVERALL COOLING AND HAVE AGAIN SIDED WITH THE LAV NUMBERS...AND AM FORECASTING LOWS AROUND 60 IN THE FAR WESTERN ZONES...TO NEAR 70 ALONG THE GRAND STRAND.
-- End Changed Discussion --
&& .SHORT TERM /6 AM SUNDAY MORNING THROUGH MONDAY NIGHT/... AS OF 3 PM SATURDAY...UPPER RIDGE OVER EASTERN CONUS BREAKS DOWN THROUGH THE SHORT TERM AS A SERIES OF STRONG SHORT WAVES DROP ACROSS NEW ENGLAND AND THE GREAT LAKES REGION. THE SURFACE PICTURE IS A LITTLE MUDDLED DUE TO A WEAK PRESSURE PATTERN AND A DIVERGENCE OF MODEL SOLUTIONS. HOWEVER...A CONSENSUS OF GUIDANCE HAS A FRONTAL SYSTEM DRAPED ACROSS THE DEEP SOUTH ON SUNDAY LIFTING NORTH ON MONDAY INTO COASTAL GEORGIA AND SOUTH CAROLINA. INCREASING MOISTURE ADVECTION WILL MAKE FOR A CLOUDY MONDAY WITH POPS STEADILY INCREASING FROM SLIGHT CHANCE IN THE MORNING TO LIKELY OVERNIGHT. SUNDAY HOWEVER LOOKS TO BE A DECENT DAY WITH MINIMAL CHANCES OF PRECIP AND A GOOD BIT OF SUN...ESPECIALLY EARLY ON. DAYTIME HEATING WILL LIKELY POP A CU FIELD IN THE AFTERNOON...AND THE CIRRUS SHIELD WILL STEADILY INCREASE IN ADVANCE OF MONDAYS FRONTAL SYSTEM. TEMPERATURES WILL BE QUITE SEASONAL THROUGH THE PERIOD. && .LONG TERM /TUESDAY THROUGH SATURDAY/... AS OF 3 PM SATURDAY...FORECAST MODELS FOR THE MEDIUM RANGE ARE IN DECENT AGREEMENT ON THE SYSTEM MOVING ACROSS THE SOUTHEAST DURING THE FIRST COUPLE OF DAYS. BOTH THE GFS AND ECMWF OPERATIONAL MODELS SHOW A RATHER LETHARGIC SHORTWAVE THAT WAVERS BETWEEN AN OPEN WAVE AND CLOSED LOW. I HAVE MAINTAINED THE GOOD CHANCE OF SHOWERS FOR THE FIRST PART OF TUESDAY TRENDING DOWN THEREAFTER. THE AFOREMENTIONED OPERATIONAL MODELS DIVERGE WITH REGARDS TO THE MID LEVEL PATTERN FOR THE REMAINDER OF THE PERIOD. THE GFS KEEPS A WEAKNESS AROUND THE AREA...MUCH LIKE WE HAVE SEEN THIS WEEK WHILE THE ECMWF HAS A MORE PROGRESSIVE SOLUTION. WPC FAVORS MORE BLENDING WITH ECMWF SOLUTIONS SO I HAVE BACKED OFF THE SLIGHT CHANCE POPS LINGERING INTO WEDNESDAY AND THURSDAY. BEYOND THIS...A STRONG SHORTWAVE MOVING THROUGH THE OHIO VALLEY AND ATTENDANT COLD FRONT MOVE ACROSS LATE FRIDAY AND SATURDAY. AT THIS POINT THE FRONT LOOKS TO BE MOISTURE STARVED AND INTRODUCED LOWER CHANCE POPS FOR THE NEW DAY OF THE FORECAST PERIOD...SATURDAY. REGARDING TEMPERATURES...I GENERALLY ADDED A DEGREE OR TWO ACROSS THE BOARD TO WPC GUIDANCE AS THE WESTERLY FLOW THAT IS FORECAST TO DEVELOP SHOULD ALLOW A DOWNSLOPE COMPONENT TO WARRANT. HOWEVER MOST VALUES ARE WITHIN A FEW DEGREES OF CLIMATOLOGY. && .AVIATION /00Z SUNDAY THROUGH THURSDAY/...
-- Changed Discussion --
AS OF 00Z...LINGERING MVFR CIGS AT KCRE/KMYR OVER THE NEXT FEW HOURS...AND POSSIBLY AGAIN ALONG THE COAST JUST BEFORE DAYBREAK. OTHERWISE EXPECT VFR AS HIGH PRESSURE CONTINUES TO BUILD ACROSS THE AREA WITH A WEAKENING COASTAL TROUGH OFFSHORE. LATEST RADAR DEPICTS LIGHT SHOWERS OFFSHORE BUT AS THEY CONTINUE TO MOVE TOWARDS THE COAST...THEY CONTINUE TO WEAKEN AND ESSENTIALLY DISSIPATE. LATEST OBS INDICATE VFR PREVAILS ACROSS THE AREA THIS EVENING WITH THE EXCEPTION OF MVFR DUE TO LOW CIGS AT KMYR. ANTICIPATE POSSIBILITY OF MVFR DUE TO LOW CIGS TO LINGER OVER THE NEXT FEW HOURS AT KCRE/KMYR...AND THE POSSIBLY RE-OCCUR BEFORE DAYBREAK ALONG THE COAST. OTHERWISE EXPECT VFR THROUGH THE OVERNIGHT HOURS WITH NORTHEAST WINDS 5 TO 10 KTS. ON SUNDAY...ANY MVFR DUE TO LOW CIGS COULD LINGER INTO THE LATE MORNING HOURS...BUT CONDITIONS WILL GRADUALLY IMPROVE TO VFR WITH PERSISTENT NORTHEAST WINDS. EXTENDED OUTLOOK...CHANCE OF SHOWERS/MVFR MONDAY AND TUESDAY AS LOW PRESSURE MOVES ACROSS THE SOUTHEAST. MVFR/IFR CIGS ON WEDNESDAY/ POSSIBLY THURSDAY.
-- End Changed Discussion --
&& .MARINE...
-- Changed Discussion --
NEAR TERM /THROUGH TONIGHT/... AS OF 730 PM SATURDAY...SCA WILL BE LOWERED TO SCEC FOR THE ILM NC WATERS...AND A SCEC WILL REMAIN IN EFFECT FOR THE ILM SC WATERS. THE SCEC FOR ALL WATERS WILL REMAIN IN EFFECT THRU MIDDAY SUNDAY. MODESTLY TIGHTENED SFC PG ACROSS THE WATERS WILL PRODUCE NE 15 TO OCCASIONALLY 20 KT OF WINDS OVERNIGHT. SIGNIFICANT SEAS WILL RUN 3 TO 5 FT...EXCEPT 2 TO 4 FT SOUTH OF CAPE FEAR TO LITTLE RIVER INLET. DOMINANT PERIODS WILL RUN 5 TO 6 SECONDS. NOT MUCH OF ANY GROUND SWELL TO SPEAK OF. PREVIOUS DISCUSSION.............................................. AS OF 3 PM SATURDAY...HIGH PRESSURE WEDGING DOWN THE COAST AND A COASTAL TROUGH POSITIONED ABOUT 50 MILES OFFSHORE...CONTINUE TO KEEP THE COASTAL WATERS PINCHED IN BETWEEN. THIS IS CREATING GUSTY NE WINDS OF 15-25 KTS...AND SEAS OF 3 TO 6 FT THIS AFTN. A SLOW DECREASE IN WIND SPEEDS IS EXPECTED TONIGHT AS THE HIGH PRESSURE PUSHES FURTHER SOUTH...WEAKENING THE GRADIENT...BUT SPEEDS OF 10-20 KTS WILL REMAIN INTO SUNDAY MORNING. HOWEVER...THE SLIGHTLY LOWER SPEEDS WILL ALLOW WAVE HEIGHTS TO DROP TO BELOW 6 FT...AND THE SCA SHOULD BE ABLE TO EXPIRE AT 8PM FOR THE NORTHERN WATERS. THEREAFTER...A SCEC MAY BE NEEDED FOR THE MUCH OF THE REST OF THE NEAR TERM AS SEAS ARE FORECAST TO REMAIN 3-5 FT. SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/... AS OF 3 PM SATURDAY...NORTHEAST WINDS OF 10 TO 15 KTS ON SUNDAY WILL DECREASE TO AROUND 10 KTS OR LESS ON MONDAY AS OVERALL PRESSURE GRADIENT SLACKENS. SEAS OF AROUND 3 FT ON SUNDAY WILL DECREASE TO AROUND 2 FT ON MONDAY. LONG TERM /TUESDAY THROUGH THURSDAY/... AS OF 3 PM SATURDAY...A MODEST NORTHEASTERLY FLOW WILL GREET MARINERS TUESDAY MORNING ALONG WITH WIDESPREAD RAINFALL. WIND SPEEDS WILL BE LIGHT INITIALLY...LESS THAN TEN KNOTS. AS WE PROGRESS INTO EARLY WEDNESDAY...THE FLOW WILL BACK TO MORE OF A DUE NORTHERLY DIRECTION AND INCREASE TO 10-15 KNOTS AS THE LOW PRESSURE SYSTEM PULLS AWAY SLOWLY. BY THE END OF THE PERIOD WINDS ARE BACK TO A NORTHEAST DIRECTION AS HIGH PRESSURE BUILDS DOWN FROM THE CANADIAN MARITIMES. SIGNIFICANT SEAS SHOULD BE ON THE LOW SIDE CITING THE LACK OF STRONG WINDS AND CHANGES IN THE FETCH...GENERALLY 1-3 TO 2-4 FEET.
-- End Changed Discussion --
&& .ILM WATCHES/WARNINGS/ADVISORIES...
-- Changed Discussion --
SC...NONE. NC...NONE. MARINE...NONE.
-- End Changed Discussion --
&& $$ SYNOPSIS...REK NEAR TERM...DCH/JDW SHORT TERM...REK LONG TERM...SHK AVIATION...SGL

USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.