Area Forecast Discussion
Issued by NWS Wilmington, NC

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000 FXUS62 KILM 172341 AFDILM Area Forecast Discussion National Weather Service Wilmington NC 740 PM EDT Sat Mar 17 2018 .SYNOPSIS...Mild temperatures will prevail tonight ahead of an approaching cold front, that will cross the coast early Sunday. Lingering clouds and slightly cooler temperatures will be featured on Sunday. A warming trend can be expected early next week as a storm system approaches. Periods of rain and showers Monday night through Wednesday, may transition to light snow Wednesday night before drier air sets in Thursday. Accumulations are not expected because of the relatively warmer ground. A low pressure system will approach the coast next weekend. && .NEAR TERM /THROUGH SUNDAY/... As of 344 PM Saturday...Front has wavered back north as a warm front, with warm and moister gusty southwesterly flow across the area. Temps up around 70 this aftn will slowly drop, maintaining a mild evening. Sounding profiles and time heights showed a decent layer of moisture between 4k and 14k ft this afternoon, but diminishing into early this evening. Therefore expect some late day sunshine mixing in with the clouds. Gusty SW winds will also diminish this evening. Low pressure will develop along the front as a potent shortwave drives the boundary back south as a cold front through Sunday morning. The best chc of pcp tonight will be over NC where better upper level support exists, but a low chc will exist along the actual front as it drops south into early Sun morning. Soundings show some elevated instability with limited moisture over much of the area, but heading farther north into NC, where better moisture and upper level support exists, in warm and moist air on the south side of front, there exists limited potential for elevated convection early Sun morning. Therefore, included a slight chc of tstms within the few hours leading up to sunrise along the northern tier counties. Overall expect a low end QPF with a most of SC not seeing any pcp. Temps ahead of the front overnight will remain on the warm side, in the 50s to close to 60, but as front moves through early morning, temps will drop. Lows will fall to near 50 north to the mid 50s to the south closer to daybreak as front drops south. Southwest winds will veer around to the north behind front as it drops south through the area early Sun morning. Any lingering chc of pcp through the morning will lead to drying by Sun afternoon. Pcp water values up near 1.4 inches ahead of the front will drop to near a half inch air mass clears out in drier northerly flow as high pressure builds in. Max temps on Sunday will be near 60 over SE NC, but will reach closer to 70 in NE SC. && .SHORT TERM /SUNDAY NIGHT THROUGH MONDAY NIGHT/... As of 344 PM Saturday...ECMWF/GFS both show an upper low across the Central Plains Sunday night. The upper low is progged to translate across the MS Valley during Monday evening. At the surface, a cold front will be aligned south of the forecast area at the onset. In the meantime, an area of isentropic lift and increasing low-level theta-E advection will bring rainfall chances back into the area Sunday night. Mentioned a slight chance of thunderstorms as well with some elevated instability present late Sunday night into Monday morning, primarily for SC zones. By early Monday evening both GFS/ECMWF position a surface low across TN with the warm front returning north across the area with decent rainfall chances continuing. Included thunderstorms during this time frame as stability decreases across the area. The ECMWF tracks the low a little further south, but given either solution our rainfall chances will be on the high end across the forecast area. Blend of MAV/MET numbers appears reasonable through the period. Would not be surprised to see the convective risk areas shifted a little farther north for Monday, but the bulk of the instability will likely stay farther south. && .LONG TERM /TUESDAY THROUGH SATURDAY/... As of 344 PM Saturday...Low pressure pulling off the coast will bring a lull Tuesday, before another low develops and brings periods of showers Tuesday night through Wednesday, changing over to snow or a rain/snow mix Wednesday evening. Forecast low temperatures and thermal profiles, depict a brief period of frozen precipitation is possible across much of the area. Sharp mid- level drying will end PCPN prior to daybreak Thursday. Significant accumulations are not expected due to warmer ground, but a "Frost` advisory, or `Freeze Warning` may be needed very early Thursday, favored over interior SE NC, but could reach into parts of NE SC. Did not include thunder this period because of stable/cooler low levels, but elevated instability will exist to some degree. QPF Tue- Wed night averages to 3/10" to 5/10". && .AVIATION /00Z SUNDAY THROUGH THURSDAY/... As of 23Z...Frontal boundary extends from the Outer Banks to western VA into eastern TN early this evening. As the boundary moves into the area overnight and early Sunday morning a few of the terminals may experience scattered showers and possibly an isolated thunderstorm. Best chance at KFLO and KLBT in the 06-08Z range and 08-10Z at the coastal terminals. A round of stratus in the wake of the front may cause IFR CIGS for a few hours in the morning before a drier column takes hold and clearing occurs thereafter. Extended outlook...Periods of MVFR Sunday through Wednesday. Chances for convection increasing Monday through Tuesday. && .MARINE... NEAR TERM /THROUGH SUNDAY/... As of 344 PM Saturday...Front is now north of the area but will once again drop south by Sun morning as potent shortwave drives it through. Gusty SW flow ahead of the front through tonight will veer around toward daybreak quite rapidly to the W-NW and then N. Overall winds up to 15 to 20 kts will drop to 10 to 15 kts after midnight and then a slight northerly surge will occur behind front, Sun morning. Seas will basically be in the 2 to 4 ft range, but expect a few 5 fters in the outer waters off of Cape Fear heading out toward Frying Pan Shoals. Looks like seas should remain below any criteria for SCEC or SCA. Although, seas just beyond our local waters will be higher due to off shore flow. SHORT TERM /SUNDAY NIGHT THROUGH MONDAY NIGHT/... As of 344 PM Saturday...Weak high pressure across eastern NC at the beginning of the period will shift eastward Monday morning. A stalled front south of the waters will begin to lift north as another area of low pressure takes shape across the MS Valley. The initial easterly wind will veer to a southeasterly direction Monday morning. Additional veering is expected as low pressure moves across NC Monday night. Thus a stronger southwest fetch will develop with Small Craft Advisory conditions possible overnight Monday. Seas will be highest in the southwest fetch late Monday night. LONG TERM /TUESDAY THROUGH THURSDAY/... As of 344 PM Saturday...This is shaping up to be a difficult marine period, as a series of strong low pressure systems impact the coast. Gusty SW winds 20-25 KT Tuesday and Tuesday night, will shift to north equally strong, if not stronger Wednesday as N and NW winds kick up in a cold air surge. Gusts to near Gale force are not out of the question Wednesday over the outer waters, with current numerical wave guidance at FPSN7 assigning 7 feet Wednesday. Very cold temperatures will greet mariners early Thursday, in a moderate, but biting, offshore wind. && .ILM WATCHES/WARNINGS/ADVISORIES... SC...None. NC...None. MARINE...None. && $$ NEAR TERM...RGZ SHORT TERM...SRP LONG TERM...MJC AVIATION...SRP is the U.S. government's official web portal to all federal, state and local government web resources and services.