Area Forecast Discussion
Issued by NWS Wilmington, NC

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372 FXUS62 KILM 291924 AFDILM AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE WILMINGTON NC 324 PM EDT FRI APR 29 2016 .SYNOPSIS... HIGH PRESSURE WILL BUILD IN WEAKLY FROM THE NORTH SATURDAY. ISOLATED SHOWERS WILL BE POSSIBLE ACROSS WESTERN AREAS SATURDAY AFTERNOON AND EVENING. LOW PRESSURE MOVING ACROSS THE MID- ATLANTIC STATES MAY BRING SEVERAL DAYS OF UNSETTLED WEATHER WITH PERIODS OF RAINFALL SUNDAY THROUGH TUESDAY. SHOWERS WILL BECOMING MORE ISOLATED ON WEDNESDAY. TEMPERATURES WILL COOL A LITTLE LATE IN THE PERIOD WITH DRY WEATHER EXPECTED THURSDAY AND FRIDAY. && .NEAR TERM /UNTIL 6 AM SATURDAY MORNING/... AS OF 3 PM FRIDAY...TODAY`S SEABREEZE HAS HOPELESSLY COMPLICATED FINDING THIS MORNING`S COLD FRONT. HOWEVER AN ARC OF LOW CLOUDS VISIBLE OFF THE SOUTH CAROLINA COAST EAST OF MURRELLS INLET AND GEORGETOWN COULD BE A PORTION OF THE OLD BOUNDARY. A VERY WEAK RIDGE OF HIGH PRESSURE POKING IN FROM THE NORTH SHOULD HELP ALLOW SURFACE WINDS TO GO CALM TONIGHT. WITH SHALLOW MOISTURE REMAINING IN PLACE FROM THE SEABREEZE AND LEFT OVER FROM THIS MORNING`S LOW STRATUS...LOOK FOR AT LEAST PATCHY FOG TO DEVELOP AFTER MIDNIGHT WITH THE BEST POTENTIAL EAST OF I-95. MUCH LIKE YESTERDAY...TODAY`S 12Z NAM REMAINS MUCH MORE HUMID IN THE BOUNDARY LAYER THAN THE 12Z GFS AND EXPLICITLY DEVELOPS WIDESPREAD LOW STRATUS TONIGHT. BOUNDARY LAYER WIND IS JUST STRONG ENOUGH THAT FOG AND/OR STRATUS ARE EQUALLY LIKELY...SO BOTH WILL BE IN THE FORECAST AFTER 2 AM. LOWS SHOULD FALL INTO THE LOWER-MID 60S. && .SHORT TERM /6 AM SATURDAY MORNING THROUGH SUNDAY NIGHT/... AS OF 3 PM FRIDAY...LOW PRESSURE SPINNING WELL EAST OF THE VIRGINIA COAST WILL PUSH ANOTHER NORTHEASTERLY SURGE DOWN OUR COAST SATURDAY MORNING. THIS SHOULD INCREASE WIND SPEEDS AS FAR SOUTH AS MYRTLE BEACH TO 10-15 MPH AND WILL HELP HOLD DAYTIME TEMPERATURES SEVERAL DEGREES COOLER THAN WHAT WE EXPERIENCED TODAY. THERE ARE GREAT DIFFERENCES BETWEEN THE 12Z NAM AND GFS WITH REGARD TO HOW MUCH LOW CLOUDINESS PERSISTS THROUGH THE DAY AFTER EARLY MORNING DEVELOPMENT. THE NAM MAINTAINS MUCH MORE CLOUDINESS AND THEREFORE HAS MUCH COOLER TEMPERATURES THAN ANY OTHER MODEL. I AM FAVORING THE WARMER/DRIER GFS WITH THE EXPECTATION THAT WE`LL SEE STRATUS ERODE SIMILARLY TO WHAT WE EXPERIENCED THIS MORNING GIVEN A SIMILAR SHALLOW DEPTH TO THE CLOUD DECK. STILL TEMPERED BY THE STRONGER ONSHORE WINDS HIGHS SHOULD REACH THE UPPER 70S NEAR THE COAST AND LOWER TO MID 80S FARTHER INLAND...WARMEST NEAR FLORENCE AND KINGSTREE. LOW PRESSURE MOVING EASTWARD FROM THE PLAINS STATES SATURDAY INTO THE OHIO VALLEY SUNDAY WILL DIRECT A SERIES OF UPPER LEVEL DISTURBANCES ACROSS THE CAROLINAS ALONG WITH PERIODS OF INCREASED MID AND HIGH LEVEL MOISTURE. OUR LOW-LEVELS WILL ALSO MOISTEN UP APPRECIABLY LEADING TO INLAND CONVECTIVE INSTABILITY OF 500 J/KG SATURDAY AND AS HIGH AS 1250 J/KG SUNDAY. I HAVE NOT RAISED FORECAST POPS ANY COMPARED TO PREVIOUS FORECASTS AND IN FACT HAVE TRIMMED THEM BACK FROM THE COAST WHERE COOLER MARITIME AIR SHOULD REDUCE EFFECTIVE INSTABILITY COMPARED TO FARTHER INLAND. A 20 POP IS FORECAST ALONG AND WEST OF I-95 SATURDAY...INCREASING TO 30-40 PERCENT SUNDAY. THE BEST COVERAGE OF SHOWERS AND STORMS SHOULD REMAIN ACROSS THE WESTERN CAROLINAS WHERE MUCH BETTER SYNOPTIC LIFT SHOULD EXIST. && .LONG TERM /MONDAY THROUGH FRIDAY/... AS OF 3 PM FRIDAY...COLD FRONT IN THE AREA AS THE PERIOD BEGINS IS EXPECTED TO STALL ACROSS OR JUST SOUTH OF THE AREA EARLY NEXT WEEK. THE PROXIMITY TO THE FRONT AND THE ABUNDANCE OF DEEP MOISTURE MON INTO WED...AN EXTENDED PERIOD OF PWATS ABOVE 1.5 INCHES IS EXPECTED...WILL KEEP PRECIP CHANCES ELEVATED FOR THE FIRST HALF OF NEXT WEEK. THERE WILL BE WAVES MOVING ALONG THE FRONT INCREASING PRECIP CHANCES AS THEY PASS...THOUGH TIMING THESE AT EXTENDED TIME RANGES IS SOMEWHAT DIFFICULT. THE PATTERN ALOFT WILL REMAIN PROGRESSIVE...DEVOID OF ANY SIGNIFICANT MID LEVEL FEATURES THAT WOULD ENHANCE OR SUPPRESS CONVECTION UNTIL TUE NIGHT OR EARLY WED. TUE INTO WED A 5H TROUGH/LOW OVER THE SOUTHWEST CONUS WILL MOVE EAST...INTERACTING WITH A MID LEVEL TROUGH DROPPING SOUTH ACROSS THE GREAT LAKES. THE EASTWARD MOVEMENT OF LONGWAVE 5H TROUGH HELPS PUSH THE STALLED FRONT AND ASSOCIATED DEEP MOISTURE OVER THE SOUTHEAST OFF THE COAST....DRYING THE REGION OUT. PLENTY OF UNCERTAINTY CONCERNING THE FATE OF THE 5H TROUGH/LOW THU FRI WITH THE GFS MORE PROGRESSIVE...MOVING THE FEATURE OFF THE COAST LATE THU. THE ECMWF IS MUCH LESS PROGRESSIVE AND KEEPS THE 5H TROUGH/LOW OVER THE SOUTHEAST INTO THE WEEKEND. BOTH SOLUTIONS DO OFFER A PERIOD OF DRY WEATHER...THOUGH THE ECMWF SOLUTION COULD YIELD AFTERNOON SHOWERS ON FRI. TEMPS ABOVE CLIMO MON THROUGH WED DIP BELOW CLIMO THU AND FRI...POTENTIALLY WELL BELOW CLIMO IF THE ECMWF SOLUTION VERIFIES. && .AVIATION /19Z FRIDAY THROUGH WEDNESDAY/... AS OF 18Z...A WARM FRONT IS LIFTING NORTH OF THE AREA WITH WINDS VEERING FROM THE NORTH TO NORTHEAST THIS AFTERNOON. EXPECT VFR THROUGH THE REMAINDER OF THE DAYLIGHT HOURS. MODEL SOUNDINGS SHOW AMPLE LOW LEVEL MOISTURE ADVECTING IN OVERNIGHT THAT WILL LEAD TO STRATUS DEVELOPMENT AND ASSOCIATED IFR CIGS IN THE EARLY MORNING HOURS. HAZE/FOG WILL ALSO DEVELOP OVERNIGHT WITH THE GREATEST VISIBILITY RESTRICTIONS LIKELY AT KFLO WHERE WINDS WILL BE THE LIGHTEST. KILM MAY HAVE THE BEST OVERALL VISIBILITIES DUE TO STRONGER MIXING. EXTENDED OUTLOOK...BRIEF MVFR/IFR POSSIBLE FROM CONVECTION SUNDAY INTO TUESDAY. OTHERWISE VFR. && .MARINE... NEAR TERM /THROUGH TONIGHT/... AS OF 3 PM FRIDAY...A WEAK COLD FRONT PUSHED SOUTH INTO NORTHERN SOUTH CAROLINA THIS MORNING. WHILE THIS FRONT IS VERY DIFFICULT TO LOCATE IN INLAND SURFACE OBSERVATIONS...AN ARC OF LOW CLOUDS PUSHING SOUTHWARD OFF THE COAST OF MURRELLS INLET AND GEORGETOWN COULD BE A REMAINING PORTION OF THE FRONT. NORTHEAST WINDS SHOULD TURN MORE SOUTHEASTERLY WITH TIME AS THE WEAK RIDGE OF HIGH PRESSURE BEHIND THE FRONT LIFTS OUT TO THE NORTH. LOW PRESSURE WELL OFF THE VIRGINIA COAST AROUND 70 DEGREES LONGITUDE WILL PUSH ANOTHER FRONTAL-LIKE SURGE SOUTHWARD LATE TONIGHT. LATEST MODELS SUGGEST THIS SURGE COULD MAKE IT AS FAR SOUTH AS CAPE FEAR BY DAYBREAK...WITH EAST-NORTHEAST WINDS INCREASING TOWARD 15 KNOTS HERE. SEAS CURRENTLY 2-3 FEET (HIGHEST NEAR AND NORTH OF CAPE FEAR) SHOULD SETTLE BACK TO AROUND 2 FEET OVERNIGHT. SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/... AS OF 3 PM FRIDAY...A RENEWED SURGE OF EAST-NORTHEAST WINDS IS EXPECTED TO MOVE DOWN THE COAST SATURDAY MORNING. THIS SURGE SHOULD DEVELOP AROUND DAYBREAK NORTH OF CAPE FEAR...SHOWING UP ALONG THE GRAND STRAND DURING THE LATE MORNING HOURS. WIND SPEEDS SHOULD INCREASE TO A SOLID 15 KT WITH SEAS BUILDING TO 3 FEET ACROSS OPEN WATERS. THIS IS THE RESULT OF LOW PRESSURE SPINNING WELL OFF THE VIRGINIA COAST. AS THIS LOW SCOOTS FARTHER OFFSHORE DURING THE DAY WIND SPEEDS SHOULD SLOWLY WEAKEN AND DIRECTIONS WILL VEER MORE SOUTHEASTERLY SATURDAY NIGHT. ATTENTION WILL THEN SHIFT TO LOW PRESSURE MOVING EASTWARD FROM THE PLAINS STATES INTO THE OHIO VALLEY SUNDAY. THIS SHOULD TURN OUR WINDS SOUTHERLY WITH SPEEDS AGAIN INCREASING TO 15 KNOTS. ALTHOUGH ISOLATED SHOWERS WILL BE POSSIBLE SUNDAY AND SUNDAY NIGHT...THE BULK OF ANY PRECIPITATION SHOULD REMAIN WELL INLAND THROUGH SUNDAY EVENING...PERHAPS JUMPING DOWN TO THE COAST LATE SUNDAY NIGHT. LONG TERM /MONDAY THROUGH WEDNESDAY/... AS OF 3 PM FRIDAY...SOUTHWEST FLOW MON WILL WEAKEN MON NIGHT INTO TUE AS SLOW MOVING COLD FRONT DROPS INTO THE AREA FROM THE NORTHWEST. FRONT PUSHES SOUTHEAST OF THE WATERS EARLY TUE...THOUGH HOW FAR SOUTH REMAINS IN QUESTION. AS EARLY AS TUE NIGHT THE FRONT WILL BE BACK IN THE AREA...LINGERING OVER OR JUST WEST OF THE WATERS THROUGH THE END OF THE PERIOD. MON WILL BE THE ONLY DAY WITH WELL DEFINED FLOW...WINDS WILL BE OUT OF THE SOUTHWEST WITH SPEEDS OF 15 TO 20 KT AND SEAS RUNNING 3 TO 5 FT. WINDS TUE AND WED WILL BE DETERMINED BY THE LOCATION OF THE FRONT...BUT GENERALLY EXPECT NORTHERLY WINDS UNDER 10 KT TUE WITH SOUTHERLY FLOW AROUND 10 KT WED. LIGHT WINDS AND CHANGEABLE DIRECTION WILL KEEP SEAS 2 TO 3 FT TUE AND WED. && .ILM WATCHES/WARNINGS/ADVISORIES... SC...NONE. NC...NONE. MARINE...NONE. && $$ NEAR TERM...TRA SHORT TERM...TRA LONG TERM...III AVIATION...REK

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