Area Forecast Discussion
Issued by NWS Wilmington, NC

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000 FXUS62 KILM 210518 AFDILM AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE WILMINGTON NC 1217 AM EDT SUN SEP 21 2014 .SYNOPSIS... DEEPENING LOW PRESSURE OFFSHORE OF SOUTH CAROLINA WILL TRACK TO THE NORTHEAST. THE LOW WILL REMAIN OFFSHORE BUT WILL BRING GUSTY WIND AND COASTAL RAIN OVERNIGHT INTO SUNDAY. A COLD FRONT WILL CROSS THE COAST ON MONDAY...BRINGING BELOW NORMAL TEMPERATURES TUESDAY AND WEDNESDAY. RAIN CHANCE MAY INCREASE LATE IN THE WEEK AS A WARM FRONT LIFTS NORTH ACROSS THE AREA. && .NEAR TERM /UNTIL 6 AM SUNDAY MORNING/... AS OF 1130 PM SATURDAY...OCEAN RAIN WITH EMBEDDED HEAVIER SHOWERS CONTINUES MAINLY OFFSHORE THIS LATE EVENING. LATEST SURFACE CHART SHOWS A SURFACE LOW POSITIONED AROUND 150 MILES SSE OF BALD HEAD ISLAND. NO WEIGHTY OR MOMENTOUS CHANGES TO THE FORECAST WERE MADE WITH THE LATE EVENING UPDATE. MINIMUM TEMPERATURES REMAIN ON TARGET WITH LOW/MID 60S INLAND TO THE UPPER 60S COASTAL INTERIOR AND 70-74 IMMEDIATE COAST AND ADJACENT ICWW LOCALS. MOST RECENT SATELLITE TRENDS SUGGEST THAT PARTIAL CLEARING MAY UNFOLD ACROSS OUR DEEP INTERIOR. AS A RESULT WE HAVE LOWERED MINIMUMS A DEGREE OR 2 FAR INLAND WHERE THIS IS EXPECTED. HIGHEST QPF VALUES REMAIN ALONG AND NEAR THE COAST. A PAUCITY OF RAINFALL COVERAGE OFFSHORE DUE TO APPROACHING DRY SLOT AND SUBSIDENCE BETWEEN BANDING FEATURES CONSTITUTES LIKELY AND HIGH SCATTERED POP VALUES ALONG AND NEAR THE COAST AS OPPOSED TO FLAT OUT CATEGORICAL/WIDESPREAD. && .SHORT TERM /6 AM SUNDAY MORNING THROUGH MONDAY NIGHT/... AS OF 3 PM SATURDAY...THE MID LEVEL COMPONENT OF THE SYSTEM CURRENTLY MOVING UP THE COAST WILL BE SHEARING OUT AND MOVING OUT QUICKLY AS WILL THE SURFACE LOW AT THE BEGINNING OF THE PERIOD. I HAVE MAINTAINED RESIDUAL MINIMAL POPS FOR THE COASTAL AREAS FOR A FEW HOURS SUNDAY TO ADDRESS. LATE SUNDAY MORNING AND AFTERNOON SHOULD SEE A RAPID CLEARING WITH HIGHS IN THE MIDDLE 80S WITH HIGHER VALUES INLAND WHERE THERE WILL BE A LONGER PERIOD OF INSOLATION. THE FORECAST THEN SHIFTS TO THE SYSTEM CURRENTLY SEEN IN WATER VAPOR IMAGERY MOVING ACROSS NORTH DAKOTA. THIS SYSTEM WILL MOVE ACROSS LATE MONDAY WITH AN ATTENDANT COLD FRONT. GUIDANCE REMAINS UNIMPRESSED WITH CONVECTION REGARDING THIS SYSTEM AND HAVE CONTINUED TO ADVERTISE SLIGHT CHANCE POPS. THE COOLER AIR MASS IN THE WAKE OF THE FRONT WILL BE THE BIGGER STORY...AND GUIDANCE IS ADVERTISING 55 IN THE MAV AND MET IN LBT FOR TUESDAY MORNING. THE MIXED BOUNDARY LAYER WILL LIKELY PRECLUDE THESE MINIMAL VALUES BUT WE COULD SEE A LOT OF UPPER 50S INLAND AT THIS TIME. && .LONG TERM /TUESDAY THROUGH SATURDAY/... AS OF 3 PM SATURDAY...RIGHT ON CUE THE AREA SEEMS TO BE IN FOR SOME FALL-LIKE WEATHER. HIGH PRESSURE CENTERED OVER THE OHIO VALLEY WILL COVER MUCH OF THE EASTERN HALF OF THE NATION. THIS IS A BIT FURTHER SOUTH THAN WHAT WAS PROGGED YESTERDAY, BETTER SUPPRESSING FRONTAL MOISTURE OFF TO OUR SOUTH FOR WHAT SHOULD AMOUNT TO A FAIR AMOUNT OF SUNSHINE. DESPITE THE SUNSHINE TEMPERATURES WILL AVERAGE A FEW DEGREES BELOW CLIMATOLOGY IN A WEAKENING COOL ADVECTION REGIME. SIMILARLY A COOL TUESDAY NIGHT IS ON TAP WITH MOST PLACES GETTING DOWN INTO THE 50S. THROUGH THE MID WEEK PERIOD HIGH PRESSURE WEDGE HOLDS ITS GROUND AT THE SURFACE. HOWEVER AS THE ANTICYCLONE JUST ABOVE THE SURFACE WEAKENS THERE WILL BE AN INCREASINGLY ONSHORE FLOW OF MOISTURE. FRICTIONAL CONVERGENCE ASIDE, THERE WON`T BE MUCH FORCING FOR PRECIPITATION AND RAINFALL AMOUNTS WILL BE QUITE LIGHT, AND MAYBE HARD-PRESSED TO MAKE MUCH INLAND PROGRESS. THIS MAY CHANGE LATE THURSDAY THROUGH SATURDAY AS THE LOW LEVEL FLOW BECOMES A BIT MORE CONVERGENT AND SOME WEAK ISENTROPIC UPGLIDE DEVELOPS ATOP THE PERSISTENT WEDGE. && .AVIATION /06Z SUNDAY THROUGH THURSDAY/...
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AS OF 06Z...SURFACE LOW PRESSURE CENTERED ABOUT 60-80 MILES SOUTHEAST OF ILM WILL MOVE NORTHEASTWARD AND AWAY FROM THE AREA TODAY. PATCHY LIGHT RAIN ALONG THE COAST SHOULD END OVER THE NEXT FEW HOURS...WITH THE DENSE MID/HIGH CLOUDS TAKING AT LEAST A FEW HOURS AFTER DAYBREAK TO CLEAR OUT. BENEATH THESE HIGHER CLOUDS IS A REGION OF LOWER STRATUS/STRATOCUMULUS HUGGING THE COAST. EARLIER IFR CEILINGS AT ILM HAVE RISEN ABOVE 1000 FEET BUT OBSERVATIONS SHOW 800-900 FOOT CEILINGS AT ISO...DPL AND OAJ. IF IFR CONDITIONS OCCUR EARLY THIS MORNING ILM SHOULD BE THE PLACE. OTHERWISE VFR CONDITIONS SHOULD DEVELOP BY DAYBREAK FOR ALL AREAS AS DRIER AIR BUILDS IN OFFSHORE BREEZES. EXTENDED OUTLOOK...GUSTY NORTHEAST WINDS WILL BECOME NORTHWEST AND DECREASE SUN AS LOW PRESSURE MOVES NE FURTHER AWAY FROM THE TERMINALS. OTHERWISE VFR SUN THROUGH WED WITH A CHANCE OF A SHOWER WITH A COLD FRONT ON MONDAY.
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&& .MARINE... NEAR TERM /THROUGH TONIGHT/... AS OF 1130 PM SATURDAY...ADVISORY HAS BEEN EXTENDED UNTIL NOON SUNDAY FOR SEA HEIGHT RECOVERY TIME. WIND SPEEDS 20-25 KT WITH WINDS NE BACKING TO N LATE. SIGNIFICANT SEAS 4 TO 7 FT. WIND DRIVEN WAVES WITH DOMINANT PERIODS IN THE 4 TO 5 SECOND PERIOD RANGE TO DOMINATE THE SIG SEAS. ISOLATED THUNDERSTORMS ON THE 0-20 NM WATERS. THE OCEAN IS HAZARDOUS TONIGHT AND EARLY SUNDAY AND NAVIGATION OFFSHORE IS DISCOURAGED. SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/... AS OF 3 PM SATURDAY...WINDS AND SEAS WILL BE ON THE DECREASE THROUGHOUT THE DAY SUNDAY AS LOW PRESSURE MOVES QUICKLY AWAY TO THE NORTHEAST. A NORTHWESTERLY FLOW WILL BACK TO THE SOUTHWEST BY DAYS END AS A FRONT APPROACHES FROM THE NORTHWEST. WIND SPEEDS WILL BE IN A 10-15 KNOT RANGE. MONDAY WILL FEATURE THE WIND SHIFT AS THE FRONT PUSHES ACROSS THE WATERS LATE IN THE DAY. EXPECT A NORTHERLY COMPONENT TO BE IN PLACE BY 0000 UTC TUESDAY THEN VEERING TO NORTHEAST BY TUESDAY AM. SPEEDS WILL INCREASE FROM NEAR TEN KNOTS LATE MONDAY TO 15-20 KNOTS TUESDAY. THERE WILL BE SOME RESIDUAL 3-5 FOOT SEAS EARLY SUNDAY DROPPING TO 2-3 FEET UNTIL EARLY TUESDAY WHEN THEY WILL INCREASE SLIGHTLY. LONG TERM /TUESDAY THROUGH THURSDAY/... AS OF 3 PM SATURDAY...HIGH PRESSURE WEDGE TO REMAIN IN PLACE FIRMLY THROUGH THE PERIOD IN A PATTERN MORE TYPICAL OF LATER INTO THE COOL SEASON. THE GRADIENT ITSELF WILL BE STRONG ENOUGH TO YIELD SMALL CRAFT ADVISORY WINDS, BUT SEAS WILL ALSO BE ADVISORY-WORTHY AREA WIDE (AMZ254 MAY HAVE A BIT OF TROUBLE DUE TO WAVE SHADOW OFF CAPE FEAR). NOT ONLY WILL THE ADVISORY BE IN EFFECT FOR THE DURATION OF THE PERIOD BUT ALSO LIKELY BEYOND AS THE WEDGE SHOWS LITTLE SIGN OF WEAKENING OR MOVING HEADING INTO THE WEEKEND. && .ILM WATCHES/WARNINGS/ADVISORIES... SC...NONE. NC...NONE. MARINE...SMALL CRAFT ADVISORY UNTIL NOON EDT SUNDAY FOR AMZ250-252-254- 256. && $$ NEAR TERM...COLBY SHORT TERM...SHK LONG TERM...BACON AVIATION...TRA

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