Area Forecast Discussion
Issued by NWS Wilmington, NC

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000 FXUS62 KILM 300529 AFDILM Area Forecast Discussion National Weather Service Wilmington NC 130 AM EDT Fri Sep 30 2016 .SYNOPSIS... A stationary front will waver along the coast through this weekend. Periods of showers with an isolated thunderstorm are possible along this front. Weak high pressure will build in early next week. Hurricane Matthew may bring increasing waves by the middle of next week. && .NEAR TERM /UNTIL 6 AM FRIDAY MORNING/... As of 1030 PM Thursday...Except for a single shower just north of Marion, SC, the radar is clear across the ILM forecast area. This should change by midnight as an upper level disturbance currently moving north across coastal Georgia reaches the area. The region of deep lift ahead of this feature should have around 1000 J/kg of elevated instability to work with, assuming a parcel lifted from around 2000-3000 ft AGL. Activity should cross the Santee River by midnight, working its way northeastward to Cape Fear by 4-6 AM. Locally heavy rainfall due to rather slow cell movement and high precipitable water values should be the main threat with these cells. In the meantime, we have an unusually humid airmass for this late in the year across the Carolinas. A nearly stationary front extends from near Augusta, GA to Columbia, SC to Hickory, NC and is actually visible on satellite imagery as a narrow line of low clouds. In areas where rain fell today and skies have cleared, areas of locally dense fog have developed, particularly around Whiteville and Elizabethtown. This fog will probably be with us for at least the next 3-4 hours, however increasing cloudiness with the incoming disturbance may destroy the ideal radiational cooling conditions we are currently experiencing, making fog more of a "patchy" to "areas" event by late tonight. Forecast lows have been bumped down a degree or two where radiational cooling is currently ongoing. This gives mainly upper 60s inland with lower to middle 70s confined to areas within 10-15 miles of the coast. && .SHORT TERM /6 AM FRIDAY MORNING THROUGH SATURDAY NIGHT/... As of 345 PM Thursday...Little change in the synoptic setup into the weekend as bowling ball of the upper low spins slowly across IN/KY before lifting into OH late in the period. At the surface, a very slow moving cold front will push eastward, likely finally crossing offshore Friday night before stalling once again. With diffluence remaining east of the upper low, and low level confluence likely persisting along and east of the boundary, more convection with periods of heavy rain is forecast Friday. The best chance for rainfall will again be the eastern third of the CWA where mid-level RH remains elevated despite a very dry punch within the dry slot working into the Pee Dee. This creates 2 distinct air-masses across just the local CWA, with PWATS forecast to drop below 1 inch well inland, while remaining at 1.5-1.75 near the coast, and inland counties may finally have a dry day Friday. By Saturday, most of the CWA is forecast to get into the drier air, but once again the immediate coast may still see no relief from this humid airmass with more showers/tstms possible along the coast. Highs both Friday and Saturday are forecast to be slightly above climo, low 80s, but will be heavily impacted by clouds and rainfall. Mins inland will drop into the upper 50s/low 60s both nights within that drier air mass, but will remain near 70 at the coast. && .LONG TERM /SUNDAY THROUGH THURSDAY/... As of 3 PM Thursday...Incredibly the relatively sharp west to east precipitable water gradient remains in place across NE SC/SE NC much of the extended period before the potential of tropical moisture late next week. In essence this brings a sensible weather forecast of chances for showers near the coast and very little along the far interior zones. This in part due to the dry mid-level air wrapped around the large upper low to the west, and the remnant presence of dry air aloft across the area even as the low pulls away from the region on Sunday. Even so a chance of showers will prevail along the eastern 1/3 of the forecast zones days 4-7 with isolated TSTMS favored nocturnally over the coastal waters, or a sea breeze pop up in the middle afternoon. Temperatures to run near to a bit above normal, especially for the minimums this period. Tempering of maximum temperatures days 6 and 7 is attributed to increasing NE flow across the area, but about normal max temp readings for early OCT. && .AVIATION /06Z FRIDAY THROUGH TUESDAY/...
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As of 06Z...Patches of IFR or lower now becoming less widespread ahead of approaching pre-frontal band of showers and should remain so for the rest of the overnight save for perhaps LBT where so much rain fell recently. Showers streaming onshore to increase in coverage predawn but only tend to MVFR with any IFR dips too brief to warrant being in TAFs. Dry slot sweeps west to east across the area this afternoon and clears things out. Slight chance of very minor visibility restrictions returning Friday night. EXTENDED OUTLOOK...Primarily VFR. Isolated to scattered afternoon showers through much the period, although limited in strength and coverage due to dry air aloft.
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&& .MARINE... NEAR TERM /THROUGH TONIGHT/... As of 1030 PM Thursday...A front remains stalled across the central Carolinas this evening, stretching from just east of Augusta, GA to just west of Columbia, SC to near Hickory, NC. Southerly winds continue across the coastal waters, and these winds should continue overnight as the front remains inland. An upper level disturbance moving northward across coastal Georgia will probably bring scattered showers and t-storms back into the area after midnight. Activity will reach the Cape Fear area late tonight and may continue into the daylight hours Friday morning. Seas average 3 feet mainly in southerly wind waves with 5-6 second periods. SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/... As of 345 PM Thursday...A cold front will be west of the waters Friday before wavering across or potentially still just inland on Saturday. This creates predominantly S/SW winds of 10-15 kts on Friday, backing to the SE around 10 kts on Saturday, again dependent on where the front stalls. A period of variable winds is possible late Friday into Saturday as the front drifts into the vicinity, but speeds will be light during that time. Seas will hover around 3 ft both Friday and Saturday with a low amplitude 9-10 sec SE swell and 2-3 ft 5 sec southerly wind wave comprising the spectrum. LONG TERM/SUNDAY THROUGH TUESDAY/... As of 3 PM Thursday...This period will be marked by 3-5 foot seas and highest seas offshore, but elevated wave heights may gradually arrive after Tuesday due to increasing swell from Hurricane Matthew. No advisories expected through Tuesday. Isolated showers and TSTMS can be expected this period and radar updates are encouraged. && .ILM WATCHES/WARNINGS/ADVISORIES... SC...None. NC...None. MARINE...None. && $$ SYNOPSIS...MJC NEAR TERM...TRA SHORT TERM...JDW LONG TERM...MJC AVIATION...mbb

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