Area Forecast Discussion
Issued by NWS Wilmington, NC
Issued by NWS Wilmington, NC
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605 FXUS62 KILM 290754 AFDILM Area Forecast Discussion National Weather Service Wilmington NC 354 AM EDT Wed May 29 2024 .SYNOPSIS... Mostly dry and relatively cooler conditions are expected through the end of the week with high pressure dominating. Unsettled weather returns towards early next week as the high moves offshore. && .NEAR TERM /THROUGH TONIGHT/... Cold front will be moving just offshore this morning. Weak sfc high pressure accompanied with WNW-NNW winds will dominate today. Drier air will be noticeable as a sfc dewpoints drop into the 60s wide. Will see some mixing this aftn with sfc dewpoints dropping into the 50s away from the immediate coast. Base of Cu field will be 5k feet and hier as a conservative estimate, likely closer to 7+k ft. With winds W-WNW off the Appalachians, could see enough downslope play (compressional heating) for todays highs breaking 90, especially as 1 moves closer to the coast. The sea breeze will limit highs, just below 90, at the immediate coast as the sfc pressure/gradient pattern relaxes allowing the onshore winds to occur. Its push well inland may be limited given increasing offshore windspeeds above 8H. End result, went slightly above guidance for maxes today. Tonight the mid-level trof axis to swing across the FA with the main dynamics and any pcpn staying well north of the FA, ie. MidAtlantic States and northward. What it does to the FA is it pushes a secondary CFP or sfc trof across the FA during this evening. This will be followed with tightening sfc pg as a much stronger high noses in from the NW, ie from the Western Great Lakes. Look for CAA and even drier air, lower sfc dewpoints, to infiltrate the FA under active NW-N winds. Tonights lows, widespread 60s, with mid to upper 60s closer to the coast and low 60s inland, especially along and west of the I-95 corridor. && .SHORT TERM /THURSDAY THROUGH FRIDAY/... Behind a dry cold front, northerly winds can be expected at the start of the period with dewpoints holding mainly in the 50s through Thursday. Mostly sunny skies and a robust subsidence inversion will yield some flat cumulus and highs in the low to mid 80s. For Thursday night into Friday, a potent shortwave is expected to dive southward through the Mid-Atlantic and pivot off the coast of the Carolinas. Meager moisture concentrated near and below 700 mb combined with lift induced by PVA ahead of this wave should primarily yield increased cloud cover and may be able to squeeze out sprinkles and perhaps some areas of light rain near and east of the Cape Fear River on Friday morning, although accumulation of 0.01" or more seems difficult to attain in this environment. Curiously, a few CAMs suggest there may be a few to several hundred J/kg of CAPE available, which could yield some briefly moderate showers if this is realized. Given this setup with limited moisture available, opted to maintain silent PoPs for measurable precip (<15%) over land with slight chance PoPs over the NC waters, focused in the morning hours. The mid-level trough axis should pass overhead around midday, with extremely dry air aloft and subsidence taking over thereafter. A mostly sunny afternoon with passing flat cumulus is otherwise expected with highs around 80F. Morning lows should be in the upper 50s to low 60s given a continuation of dry dewpoints from the near-term period. && .LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/... Surface high pressure and mid-level ridging crest overhead late Saturday and continue into the western Atlantic on Sunday. A generally zonal flow regime looks to setup behind the ridge, with multiple shortwaves crossing the region into early next week. Whether these will be timed right to enhance or suppress daytime convection remains to be seen. However, what is more certain is that return flow around the surface high will bring increasing dewpoints, warming temperatures, and an environment more favorable for pop-up convection each afternoon. Temperatures start out chilly on Saturday morning with mid- upper 50s expected before warming into the low 80s during the afternoon. After the high moves offshore late on Saturday, a warming trend commences with both lows and highs rising steadily through the end of the period to near or above seasonal norms. && .AVIATION /07Z WEDNESDAY THROUGH SUNDAY/... As of 06Z, the front has finally snaked across the remainder of the fcst area and is now off the ILM CWA coast. A quick northerly flow behind the front will fade to 4 kt or less, possibly going calm at times. This has pushed an influx of lower dewpoints, drier air, in the low levels across the region. Guidance indicates FEW/SCT altocu in the front`s wake for the remainder of the overnight. Have kept fog at bay for the time being given the drier air. Will see a possible Cu field in the 5k to 7k foot level, possibly even hier given some of the upside down V progged soundings. Around the 7H level decent subsidence inversion to exist today thus no real vertical development expected of the cu. NW to N winds to increase to 5 to 10 kt by 13Z and hold thru the day, except a pinned sea breeze to mainly affect CRE/MYR with winds becoming onshore less than 10 kt. Extended Outlook...VFR through Sun. && .MARINE... Through Tonight... CFP early this morning will result in NW-N winds around 10 kt thru midday. By this aftn, the sfc pg relaxes and winds reverse course and become S-SW given the progged sfc pressure pattern. An active sea breeze will increase winds 10-15 kt near the coast, where SC coast may observe SSE-S aftn wind directions near the coast. A secondary CFP or sfc trof passage will occur tonight, with an even tighter sfc pg in its wake as much stronger high pressure begins to nose in from the NW. Winds become NW 10-15 kt with g20 kt. Seas generally around 2 ft today and 1 to 3 ft tonight, with the 3 footers 20 nm out given the offshore fetch direction. Waves dominated by the SE swell at 7+ sec periods today, with short period wind driven eaves dominating later tonight. Thursday through Sunday... Northerly flow at around 10 kts on Thursday morning will become variable for the afternoon and evening before a secondary cold front brings another northerly surge at around 10 kts overnight into Friday. A mid-level shortwave may bring some light rain to the NC waters on Friday morning as well, with winds veering to northeasterly late in the day and continuing through Friday night as the wave pivots through and low pressure spins up well offshore. Surface high pressure from the Great Lakes will slide southeastward on Saturday, veering winds further to easterly as the high nears the coast. The high moves offshore on Saturday night, with the flow returning to southerly on Sunday. Waves initially in the 1-2 ft range on Thursday rise slightly to 2-3 ft for the weekend. 1-2 ft wind waves will be accompanied by an east to ENE 2-3 ft swell at 7-8 seconds arriving between Friday and Saturday. && .ILM WATCHES/WARNINGS/ADVISORIES... NC...None. SC...None. MARINE...None. && $$ SYNOPSIS...ILM NEAR TERM...DCH SHORT TERM...ABW LONG TERM...ABW AVIATION...DCH MARINE...DCH/ABW