Area Forecast Discussion
Issued by NWS Wilmington, NC

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895 FXUS62 KILM 220155 AFDILM Area Forecast Discussion National Weather Service Wilmington NC 955 PM EDT Sat Oct 21 2017 .SYNOPSIS... Warm and dry weather is expected through the weekend as high pressure moves off to the northeast. A cold front will bring showers and a few thunderstorms late Monday and early Tuesday. Cooler temperatures will overspread the region through mid-week as this cold front sweeps off the coast. && .NEAR TERM /THROUGH SUNDAY/... As of 845 PM Saturday...Another tranquil night in store for the local forecast area. Winds across the majority of the FA have decoupled due to decent rad cooling conditions prevailing. Clouds that do increase across the FA during the overnight will mainly be thin to occasional opaque cirrus. The majority of the onshore movement of stratocu clouds from off the Atlantic should remain south of the ILM CWA. Have included more widespread fog but kept it patchy in coverage via latest avbl model MOS Guidance. Min temp fcst looks aok with very little tweaking needed. Previous.................................................. As of 220 PM Saturday...The pattern aloft will remain highly amplified through the near term period with a ridge across the eastern United Sates and a trough out west. The trough will shift across the plains during Sunday as the aforementioned ridge drifts farther east. Although the low-level theta-e values increase across SC during Sunday the primary axis will be found between the Mississippi River and the Appalachians. Thus with the main lift to the west and a dry column in place will not include any POPs at this time for most of the forecast area. The only exception during Sunday will be extreme southern portions of the forecast area where there may be enough low-level moisture return to support a few showers there. Temperatures will be well above normal tonight and with Sunday`s highs. Increasing high clouds could inhibit radiational cooling overnight in some areas. Also, fog is possible overnight but is not expected to become widespread. && .SHORT TERM /SUNDAY NIGHT THROUGH MONDAY NIGHT/... As of 220 PM Saturday...A deep mid level trough will affect the area through the short term period. This system is just now getting its act together out west via water vapor imagery. There remains some timing disagreement with the operational GFS and ECMWF so pops have been "stretched" to address this but the overall forecast remains intact. A mid level low will close off in the Tennessee Valley early Monday and trudge eastward by early Tuesday. As usual with a slow moving system like this there will be a series of fronts. The first being a warm front that moves across overnight Sunday. Second, a prefrontal trough associated with the main band of convection later Monday and a lagging cold front that moves across probably Tuesday. We continue to advertise high chance to likely pops and I have increased the values incrementally given the higher confidence. Low level wind fields aren`t the typical 60-70 knot deep mid latitude cyclone values at 850mb but a lower 40-50 knots as the wind fields are more diffuse with the slow moving cyclone. Still a high shear/low cape event is possible regarding severe parameters. Highlights of the temperature forecast include the possibility for some lower 80s Monday with overnight lows in the lower to middle 60s and possibly higher Tuesday morning before cold air advection arrives. && .LONG TERM /TUESDAY THROUGH SATURDAY/... As of 220 PM Saturday...A strong cold front will be in the process of moving offshore sometime near the beginning of the long term, possibly as early as daybreak Tuesday morning but based on the spread of model guidance FROPA cold be later in the day. In any case, best chances for severe wx appear to be before daybreak on Tuesday with bulk of precip during this portion of the forecast in the form of showers. Precip, along with the front, should be well offshore by Tuesday evening. Other than Saturday, remainder of the Long Term looks to be dry as high pressure moves east across the eastern Carolinas. Showers moving in advance of the next cold front may impact the area on Saturday, but model solutions are quite divergent so will keep pops on the low side. Temperatures will drop to normal for late October on Tuesday in the wake of FROPA, then even cooler for Wednesday and Thursday before a warming trend commences for the end of the week. && .AVIATION /01Z SUNDAY THROUGH THURSDAY/... As of 00Z...VFR condtions are expected through most of the period with possible MVFR conditions possible at the KLBT, KFLO, and KCRE around sunrise from fog. Otherwise winds will be light overnight before becoming easterly to southeasterly by mid-morning Sunday. Models are showing mositure increasing just below 850 mb so will introduce scattered clouds at 4000-4500 feet. Extended Outlook...Showers and thunderstorms may result in flight restrictions Mon-Tue. && .MARINE... NEAR TERM /THROUGH SUNDAY/... As of 915 PM Saturday...Center of sfc high off the mid-Atlantic states will drift further offshore tonight and Sun but will continue to ridge back to the mainland with it`s axis extending across the central Va southwestward across the western Carolinas. The sfc pg will remain relaxed but show signs of tightening during daylight Sunday. Looking at ENE to E wind directions at 10 to occasionally 15 kt wind speeds. Significant seas will run 2 to 3 ft with a few 4 footers possible across the southernmost waters. The seas will mainly be driven by a 1.5 to 2.5 foot E to ESE ground swell at 9 second periods. Previous................................................... As of 220 PM Saturday...Surface high pressure will move farther off the Jersey coast tonight through Sunday as a cold front approaches from the west. This pattern will maintain onshore flow across the waters with winds around 10 knots tonight and 10-15 knots during Sunday. The onshore fetch will result in seas of 3-4 ft by Sunday. SHORT TERM /SUNDAY NIGHT THROUGH MONDAY NIGHT/... As of 220 PM Saturday...A fairly strong storm system will affect the coastal waters through the short term period. Overnight Sunday into Monday morning winds will shift from east to southeast. By midday Monday winds will be from the south. Speeds will gradually increase from 10-15 knots to a few hours (late Monday into the evening) of 20-25 knots. Seas will increase from 2-4 feet initially to 5-7 feet during the peak winds thus a small craft advisory is likely. LONG TERM /TUESDAY THROUGH THURSDAY/... As of 220 PM Saturday...A strong cold front will be in the process of moving across the waters near the beginning of the period and should be well east of the forecast area by Tuesday night. Tuesday may start off with an advisory or exercise caution headlines in effect for all waters for seas of up to 6 ft, but do expect seas to decay early on as winds turn offshore with FROPA. Expect steadily improving conditions through mid- week. && .ILM WATCHES/WARNINGS/ADVISORIES... SC...None. NC...None. MARINE...None. && $$ SYNOPSIS...REK NEAR TERM...DCH/SRP SHORT TERM...SHK LONG TERM...REK AVIATION...DRH is the U.S. government's official web portal to all federal, state and local government web resources and services.