Area Forecast Discussion
Issued by NWS Burlington, VT

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000 FXUS61 KBTV 240550 AFDBTV Area Forecast Discussion National Weather Service Burlington VT 1250 AM EST Sat Feb 24 2018 .SYNOPSIS... An active period of weather is expected starting today lasting through upcoming weekend with two systems providing the North Country with a wintry mix to rain type of scenario. First system impacts our region on this afternoon with the second on Sunday, as the trend of above normal temperatures continue. Minor ice accumulation will be seen in eastern and central Vermont this afternoon and could produce a few slick spots during the evening commute. Gusty southeast downslope winds along the Western Slopes are possible on Sunday. && .NEAR TERM /UNTIL 2 PM THIS AFTERNOON/... As of 1248 AM EST Saturday...No significant changes from the going forecast. Previous discussions follow. Gusty winds remain in the Champlain Valley as the funneling effect has been in full force. We`ve seen winds gust as high as 52mph at Burton Island on the Lake. The winds should slowly weaken overnight as high pressure starts to build in. Some light ground fog as also developed across the region mainly where its rained on what remains of the snowpack so I added some patchy fog mention based on some wind thresholds. Otherwise forecast is in good shape. Previous discussion...Overall forecast remains in good shape for this evening and overnight as low pressure passing northeast through the Great Lakes drags a warm front through the region this evening, and the trailing cold front during the overnight. Overrunning precipitation took a bit longer to move into the region, which was a good thing as it allowed surface temps across much of the area to warm above freezing. Still seeing some pockets of freezing or slightly sub-freezing temps across portions of the eastern Adirondacks and east of the Green Mountain spine, where a mix of freezing rain, rain, and sleet continues to be possible this evening, but as surface temps continue to climb through the midnight hour we should see any mix change to plain rain by the day`s end. With this in mind, will keep current advisories in place, except for northern Franklin County in NY which we`ll cancel based on surface temps rising above freezing this hour. After midnight, cold front tracks into the forecast area from the northwest with precipitation generally diminishing but some upslope rain/snow showers will likely continue until dawn across the higher peaks with minimal snow accumulation expected. High pressure builds into the region by Saturday morning with morning clouds slowly decreasing to a partly sunny afternoon. Temps overnight don`t budge too much as cold air advection behind the front isn`t particularly strong so we`re looking at lows only in the low/mid 30s, which will set the stage for Saturday highs in the upper 30s to low 40s. Temps do cool off Saturday night as skies briefly clear under high pressure, but after midnight clouds will increase again ahead of our next system for Sunday. More on that below. && .SHORT TERM /2 PM THIS AFTERNOON THROUGH SUNDAY NIGHT/... As of 338 PM EST Friday...Precipitation will move into the North Country Sunday morning as a warm front/occluded front attempts to push into the Northeastern US. Cold air at the surface will be slow to erode out however and forecast soundings show thermal profiles that support a transition from snow to mixed precipitation to rain throughout Sunday morning. Throughout the morning hours, southwesterly geostrophic flow will increase between the parent low pressure system over the Great Lakes and the ridge of high pressure over the western Atlantic. This will advect in warmer temperatures along with enough Gulf moisture to support over a third of an inch of precipitation over the North Country. Meanwhile at the surface, an increasing pressure gradient will support strong easterly/southeasterly surface/900 mb winds that will flow perpendicular to the spine of the Green Mountains. Forecast soundings show an inversion setting up near/above mountain top, which will support mountain waves that will create strong gusty downsloping winds on the west side of the Green Mountains. Areas of northern New York north and west of the Adirondack Mountains will also see gusty winds Sunday morning. All said and done, gusts in excess of 40 mph look possible during the late morning and early afternoon. These winds will likely have an effect on the precipitation type and distribution, with downsloping areas warming and drying out faster than other places. In addition, ongoing precipitation in other areas will prevent some of the strongest winds from reaching the surface. All said and done, the precipitation and winds observed will be highly variable across the different topography of our forecast area. By mid afternoon Sunday, winds will slacken as the pressure gradient decreases. Rain will continue during the afternoon hours and taper off Sunday night after a cold front pushes east through the forecast area. && .LONG TERM /MONDAY THROUGH FRIDAY/... As of 338 PM EST Friday...By Monday, the persistent Bermuda High will start to weaken and flow will become more zonal through the week. We should see mostly quiet weather for the start of the work week with a surface high setting up to our south over the Mid Atlantic Coast. By midweek, we will see chances of light precipitation return as a weak low pressure system traverses through Ontario/Quebec to our north. Temperatures will remain above normal through the week with highs forecast generally in the 40s and lows in the upper 20s to low 30s. Any waves that do track across the the forecast area during this timeframe will likely bring a mix of rain and snow as we remain in in a baroclinic transition zone with temperatures hovering within 10 degrees or so of freezing. && .AVIATION /06Z SATURDAY THROUGH WEDNESDAY/... Through 06Z Sunday...MVFR conditions across the region overnight with periods of IFR at SLK/MSS improving by early morning. MVFR ceilings lift to VFR across the area after 12Z Saturday with northwest winds becoming gusty at 10-20kts. Outlook... Sunday: Mainly VFR, with areas MVFR and IFR possible. Strong winds with gusts to 40 kt. Definite RA, Definite PL, Definite FZRA, Likely SN. Sunday Night: VFR. NO SIG WX. Monday: VFR. NO SIG WX. Monday Night: Mainly VFR, with areas MVFR possible. NO SIG WX. Tuesday: VFR. Slight chance SHRA, Slight chance SHSN. Tuesday Night: VFR. NO SIG WX. Wednesday: Mainly VFR, with local MVFR possible. Chance SHRA, Chance SHSN. && .BTV WATCHES/WARNINGS/ADVISORIES... VT...None. NY...None. && $$ SYNOPSIS...Lahiff NEAR TERM...Deal/Lahiff/Neiles SHORT TERM...RSD LONG TERM...RSD AVIATION...Deal/Lahiff/Neiles is the U.S. government's official web portal to all federal, state and local government web resources and services.