Area Forecast Discussion
Issued by NWS Wilmington, NC

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000 FXUS62 KILM 292326 AFDILM Area Forecast Discussion National Weather Service Wilmington NC 726 PM EDT Mon May 29 2017 .SYNOPSIS... A cold front will enter the area and stall through Tuesday night. Another front will push in from the northwest on Wednesday and just barely clear the region Thursday. It may return northward as a warm front Friday. && .NEAR TERM /UNTIL 6 AM TUESDAY MORNING/... As of 7 PM Monday...Storms will move into our far interior zones in the middle evening, and currently a watch borders our zones west of I-95. It would not be surprising to see a new watch come out soon extended eastward to the coast as an upper level disturbance sustains convection well past peak heating. The main threat damaging winds and large hail. Interior NE SC still showing SFC based CAPES of 2000-3000 J/KG with effective bulk shear values between 40-60 KT across much of the area. As of 300 PM Monday...The mid level pattern remains essentially the same as the past couple of days with a relatively moist southwest flow between high pressure off the southeast coast and low pressure meandering about in the Great Lakes region. The surface pattern isn`t much to speak of other than Bermuda High pressure. These elements will remain in place through essentially Tuesday, the near term period. For pops, high resolution and other guidance has been very consistent in showing thunderstorms developing later this afternoon and moreso this evening in western North and South Carolina and eventually consolidating a bit and moving across our area, which takes up a good deal of the overnight hours. There are some indications an initial broken line or area of thunderstorms could just miss our area to the northwest but guidancs shows this area eventually filling in to the south. I have trended pops upward out of respect to the consistent guidance. SPC maintains most of the area in a slight risk highlighting our area for after dark with strong winds and hail the primary threats. For Tuesday, similar progression as today with a stable NVA scenario in the morning hours. Guidance shows a more diffuse pattern of convection for the afternoon hours and we are still advertising pops, although the better chances appear to be shaping up for tonight. Thermal profiles appear to be unchanged from today for Tuesday, at least on the 12 UTC guidance and Tuesday may actually be just as warm as today as we may fall just short of the lower 90s expected today. Overnight lows, stuffy once again mostly in the 70s with maybe an upper 60 or two once again assisted by thunderstorm cooled air. && .SHORT TERM /6 AM TUESDAY MORNING THROUGH WEDNESDAY NIGHT/... As of 300 PM Monday...Frontal boundary stalled right along the coast Tuesday night. So even as some weak vorticity energy passes overhead the area should be too stable for anything other than very isolated showers. And although heading into Wednesday a piedmont trough/weak front does form west of here most guidance keeps the deep layer moisture off the coast. This should once again keep minimized the rain chances over land, the sea breeze being the most likely culprit in bringing an isolated thunderstorm. Temperatures through the period will average about 3 degrees above seasonable norms. && .LONG TERM /THURSDAY THROUGH MONDAY/... As of 300 PM Monday...An active weather pattern expected during this period...mainly after Thursday. Looking at the longwave pattern aloft...the FA will remain basically under the influence of an upper trof at the start of this period(Thursday). Models develop split upper flow across the area by the weekend with west to nw flow from Canada associated with the longwave trof...and at the same time, flow from the lower latitudes with some Pacific and Gulf of Mexico influences. With the mean trof axis remaining just west of the FA, mid- level s/w trofs from 2 different origins will be able to track across the FA or in close proximity. Avbl moisture will not be a problem. At the sfc, short-lived dry high pressure from the NW will affect the FA on Thu. There-after, the high anchored well off the SE U.S. Coast will ridge back to the U.S. with it`s axis extending inland vcnty of GA-FL, well south of the FA. A sfc cold front will drop to the FA late Fri and likely stalling across a portion of the ILM CWA during the upcoming weekend and into next week. POPs will be at their lowest during Thu then ramping up slowly Fri and peaking during the weekend into next week. Any mid-level s/w trofs ie. upper disturbances, that affect the FA will likely be the factor that determines whether severe thunderstorms will occur. I might be overly optimistic in pushing the stalled front south of the FA by Mon, given the time of year. Max temperatures will run at or slightly hier than normal depending on cloud cover and pcpn occurrence. Min temps will run likely 5+ degrees above normal. && .AVIATION /00Z TUESDAY THROUGH SATURDAY/...
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As of 00Z...Somewhat of a repeat of Sunday`s scenario with mostly VFR conditions expected through the period, although a possibility of strong thunderstorms developing later this evening across the western areas and traversing the entire area slowly west to east overnight, hence the numerous PROB 30 groups in the TAF`s. Convection off the coast before daybreak, with VFR Tuesday 12z-18z, then isolated convection 18z-00z. Extended Outlook...MVFR/IFR conditions are possible in thunderstorms Tuesday, mainly during evening aft 00z. More typical scattered showers and thunderstorms are possible Wednesday through Friday.
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&& .MARINE... NEAR TERM /UNTIL 6 AM TUESDAY MORNING/... As of 700 PM Monday...Expect mostly southwest winds 10-15 knot range through the period. The speeds will peak once again this evening but generally be a little lighter than Sunday evening. A weak surface through will follow expected convection early Tuesday morning but it appears it doesn`t have the push the one had earlier today to allow a few hours of westerly flow. Significant seas should stay close to two feet through the period. Strong storms may approach the near shore waters in the late evening or just after midnight. The storms will be capable of pushing wind gusts to 50 KT. Mariners should keep a watch on radar overnight. SHORT TERM /6 AM TUESDAY MORNING THROUGH WEDNESDAY NIGHT/... As of 300 PM Monday... Very light SW flow expected Tuesday night as a frontal boundary stalls along the coastline. This flow regime and minimal seas will persist into Wednesday and only gradually increase by about 5 kt heading into later Wednesday and Wednesday night in response to a piedmont trough developing further inland. LONG TERM /THURSDAY THROUGH SATURDAY/... As of 300 PM Monday...A frontal boundary at the start of Thu will waver east and south of the local waters before dissipating altogether. High pressure having dropped in from the NW will temporarily prevail during Thu with offshore winds backing to the SW by the end of the day. For Fri thru Sat, the high centered well offshore from the SE U.S. coast will be the primary driver for winds across the local waters. With the sfc ridge axis extending west and inland near the GA-FL coasts, wind directions will primarily be from the SW. The sfc pg does tighten during Fri into the upcoming weekend and could see SCEC thresholds being met if this trend continues. Initially, significant seas will be driven by both a weak NE 8+ second period ground swell and locally produced wind waves. But by the weekend, 3 to 6 second period wind driven waves will dominate the seas spectrum per latest Wavewatch3 and Swan model data. Could see 5 footers during the weekend, with SCEC type conditions. && .ILM WATCHES/WARNINGS/ADVISORIES... SC...None. NC...None. MARINE...None. && $$ SYNOPSIS...MBB/8 NEAR TERM...SHK/8 SHORT TERM...MBB LONG TERM...DCH AVIATION...8 is the U.S. government's official web portal to all federal, state and local government web resources and services.