Area Forecast Discussion
Issued by NWS Wilmington, NC

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558 FXUS62 KILM 211518 AFDILM Area Forecast Discussion National Weather Service Wilmington NC 1120 AM EDT Sat Oct 21 2017 .SYNOPSIS... Warm and dry weather is expected through the weekend, as high pressure moves off to the northeast. A coastal front will bring showers and a few thunderstorms late Monday and Tuesday. Cooler temperatures will overspread the region through mid-week, as a cold front sweeps off the coast. && .NEAR TERM /THROUGH TONIGHT/... As of 915 AM Saturday...Surface high pressure in place along the East Coast along with ridging aloft will result in another warm and dry day. Water vapor imagery shows moisture streaming up from the Gulf of Mexico, however the position of the mid/upper ridge will keep the bulk of this plume west of the forecast area through tonight. Good insolation today will yield high temperatures around 80F most locations. Some high level moisture wilL increase overnight and could impact low temperatures, which are expected to range a couple categories above normal. && .SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/... As of 333 AM Saturday...The weekend will close out with plenty sunshine, and above normal temperatures. Moisture advection will increase Monday bringing clouds, and rain chances late Monday as a semi-tropical coastal warm front lifts north. This will allow for another warm day Monday in this late october, even with increasing clouds. Rain chances will peak Monday night into early Tuesday as moisture and over-running aloft increase ahead of an approaching system. The moisture sources include SFC-700 mb Atlantic and H7-H4 Gulf taps. This is shown well in model animations of PWAT, depicting an elevated swath of precipitable water surging through 00z-12z Tuesday. No cool air, as the WAA pattern prevails this period, but a chance of rainfall, with current QPF over a half inland along i-95 and quarter inch near the coast Monday night. && .LONG TERM /TUESDAY THROUGH FRIDAY/... As of 3 PM Friday...Week begins with highly amplified pattern over the eastern CONUS. Deep 5h trough, which may or may not become briefly cutoff, will be over the Mississippi Valley Mon morning and steadily moving east, pushing a cold front with it. Mid-level ridging along the Southeast will also shift east, but the rate at which these features move ultimately determines when showers and thunderstorms ahead of and along the front reach the area. Strong warm advection ahead of the front will push temps close to 10 degrees above normal Mon while ensuring abundant moisture. Still to early to say if strong or severe storms are a threat but low level jet Mon night and Tue will be 40-50 kt so at least some potential exists. Front crosses the area during Tue but cold advection will be delayed and temps will be near to slightly above climo. A shortwave dropping southeast across the western Great Lakes and into the OH/KY Valleys Tue night drives a cold surge into the southeast Wed. Cold advection will drop 850 temps from low teens late Tue to near zero Wed night, ushering in a 36 to 48 hour period of temperatures 5 to 10 degrees below climo. Mid-level trough axis shifts off the coast Thu morning and lifts northeast during the day. Warm advection will already be under way at this point but cold air will linger at the surface through Thu. Thu night or Fri will see temperatures return to levels typical of late October in the southeast. && .AVIATION /18Z SATURDAY THROUGH THURSDAY/...
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As of 16Z...Cirrus is spilling over the ridge and will become broken later today. Mainly onshore flow will become calm this evening with continued broken cirrus. Inland terminals may see a brief period of MVFR fog around sunrise. Sunday, continued high clouds with a stratocu ceiling possible at the inland terminals toward the end of the forecast period. Extended Outlook...Showers and thunderstorms may result in flight restrictions Mon-Tue.
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&& .MARINE... NEAR TERM /THROUGH TONIGHT/... As of 915 AM Saturday...Surface high pressure stretching from the Carolinas to the Mid-Atlantic region will maintain northeast to easterly flow across the coastal waters through tonight. The pressure gradient is fairly weak and winds will be around 10 kts or less. Seas will be 3 ft or less as well. SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/... As of 333 AM Saturday...A welcoming marine environment greets mariners Sunday, but conditions deteriorate Monday as a coastal front ahead of an approach storm system moves north across the 0-20 NM waters. This will bring limited visibility in rain and isolated TSTMS Monday night and early Tuesday. A small craft advisory will likely be needed from Monday afternoon through Tuesday, as SE-S winds gusts between 20-25 kt, and seas offshore build to 7-8 ft overnight into Tuesday. Sunday`s sea spectrum includes 1 ft E waves every 4-5 seconds and ESE waves 2 ft every 9 seconds. SE wave energy will begin to increase wave amplitude Monday, primarily in 6-7 second intervals. LONG TERM /TUESDAY THROUGH WEDNESDAY/... As of 3 PM Friday...Cold front approaching from the west will lead to increasing southerly flow on Mon. Winds start out east- southeast 10 to 15 kt but turn more southerly during the day, increasing to a solid 15 kt later in the day. Winds peak at 20 to 25 kt late Mon night and continue in the 20 to 25 kt range into Tue evening before dropping under 20 kt Tue evening/night and shifting to offshore as the front passes. Seas ahead of the front will build to 5 to 7 ft Mon night and exceed 8 ft in places on Tue. Headlines will likely be raised early Mon night and continue through Tue and into the first part of Tue night. Combination of offshore flow and decreased speeds late Tue night and Wed should allow conditions to drop below headline thresholds. Cold advection following the front is delayed so offshore flow will not be strong right behind the front. However cold air is expected to arrive near the end of the period and offshore winds approach 20 kt Wed night. && .ILM WATCHES/WARNINGS/ADVISORIES... SC...None. NC...None. MARINE...None. && $$ NEAR TERM...SRP SHORT TERM...MJC LONG TERM...III AVIATION...43 is the U.S. government's official web portal to all federal, state and local government web resources and services.