Area Forecast Discussion
Issued by NWS Wilmington, NC

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000 FXUS62 KILM 210532 AFDILM Area Forecast Discussion National Weather Service Wilmington NC 1232 AM EST Tue Feb 21 2017 .SYNOPSIS... Temperatures will remain unseasonably warm through much of the week. High pressure will slowly build across the area through Tuesday, shifting offshore Wednesday. A trough of low pressure will bring increased cloudiness and some showers mid week. Near record warmth will come Friday and Saturday with an increasing chance of showers ahead of an approaching cold front Friday night into Saturday. Cooler and drier high pressure will build in behind the cold front Saturday night into early next week. && .NEAR TERM /UNTIL 6 AM THIS MORNING/... As of 930 PM Monday...A big dirty upper ridge covers the Southeastern United States this evening. Saturation throughout the 400-250 mb layer (approximately 24000-36000 feet AGL) will maintain plenty of cirrus through the night and into Tuesday. Forecast lows are already on the upper end of the guidance envelope for most locations so no updates are planned to temperatures, still anticipated to fall into the mid 40s inland with upper 40s to around 50 at the immediate coast. Surface high pressure centered way up over Quebec extends a ridge axis down the U.S. East Coast into the coastal Carolinas. Sea level pressures should rise by up to 4 millibars across northern North Carolina between 00z and 12z, while smaller pressure rises are anticipated over South Carolina. This tightening of the gradient will strengthen winds offshore and also just above the partially decoupled boundary layer over land. East to northeast surface winds around 5 mph should continue overnight. && .SHORT TERM /6 AM THIS MORNING THROUGH WEDNESDAY NIGHT/... As of 300 PM Monday...An upper ridge will continue to drift eastward with its axis migrating offshore Tue afternoon and evening. At the surface, high pressure centered across New England and the northeastern states will ridge across the eastern Carolinas. Low pressure along the Gulf coast Tue will move to south Florida Wed night. An onshore flow will allow marine stratocumulus to rotate inland and these clouds should be most prevalent along the coast Tue afternoon. A series of shortwave troughs, embedded in developing WNW flow will bring a general increase in cloud cover, from W to E Tue night through Wed night. There may be some late night fog Tue night as onshore flow brings increasing dewpoints. The column does moisten adequately enough to support the inclusion of a small risk for showers, mainly Wed afternoon and eve and these look to be largely diurnally driven. The shower risk Wed eve will shift offshore, but a developing coastal trough may skirt the coast and will include a small risk for showers along the coast overnight Wed. Perhaps another round of fog or even stratus Wed night as onshore flow keeps the low levels moist. Cooler air at 850 mb on Tue and an onshore flow should keep temps from rising above the mid and upper 60s along the more coastal environs while the beaches may be stymied in the lower 60s. Further inland, it should be at least a couple degrees warmer, around 70. A good deal of clouds will be around Wed, but the column will be a little warmer. Despite the onshore flow, we think lower to mid 70s will be quite common away from the cooling impacts of the ocean. The immediate coast should not rise out of the 60s. Lows will be in the 50s through the period, so it certainly will not feel like February. && .LONG TERM /THURSDAY THROUGH MONDAY/... As of 300 PM Monday...Medium range guidance remains fairly consistent on the events for the extended period. The flow will show a little amplitude through the first half of the period as a shortwave rides through the midwest and Ohio valleys with a cold front at the surface. Models have trended lower with the moisture with this system but we maintain some low chance pops for Friday into the day Saturday. We also have slight chance pops for Thursday via the sea breeze or pulse type convection. Later Saturday through Monday should be mostly dry. Temperatures remain well above climatology backing off a little Sunday and Monday. && .AVIATION /06Z TUESDAY THROUGH SATURDAY/...
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As of 06Z...Expect VFR through the valid TAF period as high pressure continues to build into the area. Mainly FEW/SCT cirrus expected overnight into Tuesday as easterly winds remain around 5 kts. After daybreak, northeast winds in the morning will return to easterly in the afternoon, persisting around 5 to 10 kts. Cirrus will continue to stream across the area as well, becoming BKN/OVC towards the end of the period. Extended Outlook... Patchy fog possible late Tuesday night. Isolated showers late Wednesday through Thursday. Showers possible Saturday with a cold front. Otherwise expect VFR.
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&& .MARINE... NEAR TERM /THROUGH TONIGHT/... As of 930 PM Monday...Pressures should rise across northern North Carolina by around 4 millibars tonight, while only a 2 millibar pressure rise is expected over South Carolina. This means we`ll have a steadily tightening pressure gradient, with wind speeds increasing overnight to 12-16 knots with some higher gusts offshore. Seas currently around 2 feet should begin to build shortly in response the increasing winds, reaching 3-4 feet by late tonight, highest over the Cape Fear area waters. The current forecast has all this well handled, and no changes are needed. SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/... As of 300 PM Monday...The center of surface high pressure will drift south and be centered just offshore of the eastern Carolinas Wed, migrating further eastward Wed night. Meantime, low pressure along the Gulf Coast will move slowly southeast across the Gulf of Mexico and should be situated across south Florida Wed night. NE winds Tue morning will veer to easterly during Tue afternoon and SE Tue night. An Ese to SE wind will prevail Wed and Wed night. The strongest winds this period are expected Tue, up to 10 to 15 kt. A tightening pressure gradient is expected to develop to our S Wed night. Seas will be 2 to 4 ft Tue morning. Seas will trend a little lower Tue afternoon and Tue night, 2 to 3 ft. Seas will be building to our S Wed and Wed night and some of there higher seas will be working their way into our waters late in the period. LONG TERM /THURSDAY THROUGH SATURDAY/... As of 300 PM Monday...Relatively light wind fields for most of the day Thursday and even into Friday with a southeast flow of ten knots or so. Winds finally pick up modestly Saturday ahead and in the wake of a cold front on the order of 10-15 knots from the southwest. Significant seas will be 1-3 feet Thursday into Friday then increase considerably as a decent swell component moves in from the southeast. && .ILM WATCHES/WARNINGS/ADVISORIES... SC...None. NC...None. MARINE...None. && $$ SYNOPSIS...SHK NEAR TERM...TRA SHORT TERM...RJD LONG TERM...SHK AVIATION...REK/SGL MARINE...RJD/TRA/SHK is the U.S. government's official web portal to all federal, state and local government web resources and services.