Area Forecast Discussion
Issued by NWS Wilmington, NC

Current Version | Previous Version | Graphics & Text | Print | Product List | Glossary On
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50
-- Remove Highlighting --
-- Discussion containing changed information from previous version are highlighted. --
000 FXUS62 KILM 242341 AFDILM Area Forecast Discussion National Weather Service Wilmington NC 641 PM EST Sat Feb 24 2018 .SYNOPSIS... Warm weather will continue until a cold front arrives on Monday. Temperatures will only be cooled to normal Tuesday and Wednesday. Another cold front is expected late Thursday. && .NEAR TERM /THROUGH SUNDAY/... As of 645 PM Saturday...Skies have cleared rapidly this evening as the daytime cumulus clouds dissipated with the loss of heating. The big question of the night is how much low stratus and/or fog will develop late? Compared to last night it appears we`re slightly drier with dewpoints 1-3 degrees lower across the board. It also appears forecast wind speeds at the surface and at the 975 mb level (appx. 1000 feet up) are higher than last night. This argues for a lower fog risk, but could still allow some low stratus to develop late tonight into early Sunday morning. I`ve made a couple of edits to the forecast to forecast nearly clear skies through midnight and downplay fog chances to "patchy." I`ve also removed the slight chance of showers along the coast late as it appears the convergent plume of moisture from the Gulf Stream that fed showers into Cape Fear last night will be absent given the veered low-level wind directions expected tonight. No significant changes have been made to forecast low temperatures, still expected to range from 60-63 which is normal for highs this time of year! Discussion from 300 PM follows... Chartreuse colors becoming more common across our landscape, as prolonged spring-like warmth spreads across the region. This exceptionally mild pattern, which has also been record breaking, will continue through Sunday. Low- level thickness amplification over the interior Sunday afternoon ahead of an approaching cold front, in vigorous SW wind flow, will provide an opportunity to establish new record highs. Record maximum temperatures for Sunday 2/25 include, ILM 81 in 1930 forecast is 81, FLO 79 in 2017 forecast 84, and CRE 77 in 1949 forecast 76. A formidable dry cap aloft will prevent deep convection through this forecast period, but a few showers may scrape the coast and graze the Cape Fear region overnight into early Sunday. An encroachment of showers late Sunday afternoon could begin to wet I-95, as the forthcoming surface trough, moves eastward out of the Appalachian foothills, where more concentrated SHRA will reside. Radiational fog again has potential to become widespread inland tonight, as skies become clear in dissolving diurnal cumulus. Increasing low-level jet although not strong, could produce patches of low-stratus but good surface visibility instead. A low-end threat of sea fog intrusion will remain in place for the coastal zones. && .SHORT TERM /SUNDAY NIGHT THROUGH MONDAY NIGHT/... As of 300 PM Saturday...Cold front moves into the area Sun night, pushed east by movement of stacked low across the western Great Lakes. Elongated 5h ridge off the Southeast coast promotes deep southwest flow, leading to increasing moisture over the Southeast Sun night. Precipitable water reaches 1.7 inches in latest soundings which is right around the all time max based on sounding climatology. Front ends up laying parallel to the deep southwest flow as it settles into the area. The front lingers on Mon before a shortwave, emerging from the Desert Southwest Sun, helps drive the front south and east of the area, opening the door for modified high pressure Mon night. Best precip chances during the period will be Sun night and most of Mon. Abundance of deep moisture in the area coupled with low level convergence will lead to periods of showers with potential for isolated thunder, especially Mon. There will also be a series of weak shortwaves moving up the west side of the elongated ridge. No single wave is particularly strong but these features will likely help enhance any ongoing convection. Instability and shear are limited and low level jetting is quite anemic. Thus severe weather is not likely to be an issue. Rainfall will range from a quarter inch to half an inch for most areas. Lows well above normal will continue Sun night, but there will be a change on Mon. Warm start coupled with clouds and showers results in highs in the mid to upper 60s. However, the passage of the front during the day will result in temps starting to drop during the afternoon hours. High building in Monday night will be accompanied by some modest cold advection and lows will drop into the mid 40s by the end of the period. && .LONG TERM /TUESDAY THROUGH SATURDAY/... As of 300 PM Saturday...Surface winds will be veering from NE to E as Tuesday progresses due to high pressure sliding by to our north. This veering continues Tuesday night into Wednesday paving the way for advection of warm and moist air. Clouds will increase as will rain chances though the latter may hold off until Wednesday night into Thursday with the actual surface warm front. Tough call whether or not we dry out in the warm sector, the main factor being how far north the warm front lifts. If we do catch a break in the rain it`ll be short-lived as the next mid level impulse and surface wave approach from the west. This system pushes through Thursday night into Friday morning and is starting to look rather wet. This system deepens and quickly occludes off the Delmarva coast, readily pushing some colder/seasonable air into the Carolinas. && .AVIATION /00Z SUNDAY THROUGH THURSDAY/... As of 00Z...VFR is expected at all terminals through 06Z. There is moderate to high confidence of MVFR after 06Z at KFLO/KLBT, several hours later at the coastal terminals. There will be patchy ground fog developing with MVFR vsbys, but increasing boundary layer winds should provide enough low level mixing to prevent vsbys from dropping to IFR. There is greater confidence that available moisture will lift into a MVFR cig. These cigs could possibly be at the IFR level depending on where exactly the low level inversion/s set up. Low cigs will persist until mid-morning when any inversions break. Winds gusts to 20-25 kt possible thereafter through the day. There is a low chance of showers coastal terminals 13-17Z and at KFLO/KLBT after 21Z. These will be isolated and as such are not indicated in TAFs attm. Extended Outlook...VFR with periods of SHRA/MVFR Sun night into Mon. VFR Tue. VFR with periods of SHRA/MVFR Wed/Thu. && .MARINE... NEAR TERM /THROUGH SUNDAY/... As of 645 PM Saturday...Very few changes are needed to the forecast this evening. We are still anticipating areas of sea fog to develop overnight and persist into the first few hours of Sunday, particularly over the cooler nearshore waters. Discussion from 300 PM follows... SE waves around 3 feet every 9 seconds moving through the 0-20 NM waters, with a light to moderate chop inshore to linger through afternoon. It does not appear that an `Advisory` or `Exercise Caution` headline will be needed this period, but Sunday afternoon, SW gusts to 20 KT and seas of 4 feet offshore will be common. The notable change is that dominant periods will shorten to 5 seconds, making for a much bumpier boat ride by Sunday afternoon. Inshore water temperatures remain chilly, around 60 degrees. SHORT TERM /SUNDAY NIGHT THROUGH MONDAY NIGHT/... As of 300 PM Saturday...Southwest flow at the start of the period will gradually weaken Sun night into Mon. Bermuda High will sink south and weaken as cold front slowly moves in from the west-northwest. Weakening gradient will drop speeds from 15 to 20 kt late Sun to 10 to 15 kt by daybreak Mon. The front moves over the waters later Mon with winds becoming light and variable as the boundary briefly hangs up in the area. Northerly push late Mon into Mon night drives the front south of the waters and sets up a period of modest cold advection. High building in helps pinch the gradient and the development of northeast flow will result in a cold surge Mon night Speeds increase to 15 to 20 kt as the period comes to an end. Gradually decreasing wind speeds Sun night into Mon allows seas to fall from 3 to 4 ft at the start of the period to 2 to 3 ft on Mon. Once the northeast surge develops Mon night seas will build, reaching 3 to 5 ft before the end of the period. LONG TERM /TUESDAY THROUGH THURSDAY/... As of 300 PM Saturday...High pressure progressing eastward and staying well to our north Tuesday to yield NE winds turning to E and easing. Very light winds slated for Wednesday while the veering in direction continues. Southerly flow remains established on Thursday as low pressure approaches from the west. WNA is quite aggressive in building seas up to advisory levels and is seemingly too fast. As such shaved about a foot off of guidance. && .ILM WATCHES/WARNINGS/ADVISORIES... SC...None. NC...None. MARINE...None. && $$ SYNOPSIS...MBB NEAR TERM...MJC/TRA SHORT TERM...III LONG TERM...MBB AVIATION...MRR is the U.S. government's official web portal to all federal, state and local government web resources and services.