Area Forecast Discussion
Issued by NWS Burlington, VT

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000 FXUS61 KBTV 231719 AFDBTV Area Forecast Discussion National Weather Service Burlington VT 119 PM EDT Wed May 23 2018 .SYNOPSIS... A weak cold front will cross the area today with little fanfare other than a few isolated showers or a stray storm across eastern counties. Otherwise high pressure will provide fair and seasonably warm temperatures through Friday. More uncertainty arrives by the upcoming weekend as an increase in moisture and a cold front sinking southward from Canada may lead to a period or two of showers, especially Saturday and Saturday night. && .NEAR TERM /THROUGH THURSDAY/... As of 1020 AM EDT Wednesday...Overall forecast is in good shape with just a few tweaks to sky cover and precip probs for the next few hours. Front lies north of the border and is currently interacting with some stable low clouds inhibiting any convective development. Once it crosses the border, better instability will exist so still think slight to low chance of an isolated shower and/or thunderstorms looks good through the afternoon across northeastern areas. Prior discussion... After areas of patchy morning fog and low clouds burn off, a much better day is on tap for our area as skies trend partly sunny under drying northwesterly winds. A weak cold front will be dropping southward through the area by this afternoon, behind which those winds could gust into the 15 to 20 mph range in the 100-700 pm time frame. Some weak instability and meager moisture convergence could also spark an isolated shower or storm across mainly eastern and northeastern VT during this time period as the front passes, but a warm layer near 600 mb should inhibit any convective cells from attaining overly robust levels. High temperatures will respond nicely to the increase in overall sunshine, topping out in the lower to mid 70s north and mid to upper 70s south which agrees nicely with modeled 18-21Z 925 mb thermal profiles. Then trending mainly clear over time tonight as high pressure builds east from the Great Lakes and Ohio Valley. I stuck close to a multi-model bias-corrected blend for low temperatures offering values in the lower and mid 40s in the broader valleys and from 35 to 40 across Green and Adirondack Mountain communities with some slight variability. Winds light. By Thursday the surface high builds atop and just east of our region by afternoon as light north/northwesterly flow trends south to southwesterly over time. High temperatures cool slightly (3-5 degrees) from today`s values, but all and all another outstanding day is on tap with nil pops under mostly sunny skies. && .SHORT TERM /THURSDAY NIGHT THROUGH FRIDAY/... As of 407 AM EDT Wednesday...Heights will be rising through the evening hours as high pressure continues to build heading into the weekend. Southerly flow will become westerly by mid day on Friday and temps will warm rapidly. The westerly warm air advection will bring 925mb temps of 18C to 21C over the region meaning low to mid 80s can be expected. In the Champlain valley we could see temps warm into the mid to upper 80s as BUFKIT soundings show we will mix up to around 890mb. With that mixing we`ll also see slightly drier dew points along with fairly gusty winds. Expect gusts during the morning and afternoon hours of between 25-30 mph. With the higher temps and decent mixing there`s some potential for showers to develop in the afternoon hours on Friday. Showalters turn negative across much of Northern Vermont and Northern New York after 12pm. Any showers would be isolated in nature but I certainly can`t rule out the threat. && .LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/... As of 407 AM EDT Wednesday...The weekend still presents itself as a challenging forecast. Saturday night still seems like the time period where we`ll have the best chance for rain but confidence isn`t real high on any solution. The ridge starts to break down Friday night as a front starts to drop south over the North Country. This will bring in rain along with an increase in cloud cover. Then its still a question of where does the front stall out. I`m still leaning towards the front stalling out to our south which means that we`ll be looking at possible chances for rain heading into Sunday. QPF from the global guidance is showing a bulls eye of zero rainfall during the day on Sunday. Based on the placement of the bullseye and upper level support I`m leaning towards the idea that we`ll see a modified marine airmass over Vermont with the continental airmass over northern New York. 925mb temps show a wedge of cold air with easterly flow over VT/NH and warm air over NY. So we may be too stable to be able to develop much in the way of precip on Sunday across the Champlain Valley and east across Vermont. I dont have a lot of confidence in that however. Coming out of the weekend an upper level trough does swing through the North Country and showers continue Monday into Monday night. We`ll return to near normal temps with dry air moving in as a dome of high pressure builds in for Tuesday and Wednesday. && .AVIATION /18Z WEDNESDAY THROUGH MONDAY/...
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Through 18Z Thursday...VFR conditions are expected through the period. Diurnal cumulus developing over the region this afternoon may produce a stray shower or isolated thunderstorm across northern Vermont, but will dissipate to mainly clear skies after sunset. Overnight, SKC to FEW250 is expected with light winds, with more fair weather clouds developing across the region tomorrow. Outlook... Thursday Night: VFR. NO SIG WX. Friday: VFR. Slight chance SHRA. Friday Night: Mainly VFR, with local MVFR possible. Chance SHRA. Saturday: Mainly VFR, with local IFR possible. Chance SHRA. Saturday Night: MVFR/IFR conditions possible. Likely SHRA. Sunday: Mainly VFR, with local IFR possible. Chance SHRA. Sunday Night: Mainly VFR, with local MVFR possible. Chance SHRA. Memorial Day: Mainly VFR, with local MVFR possible. Chance SHRA, Slight chance TSRA.
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&& .BTV WATCHES/WARNINGS/ADVISORIES... VT...None. NY...None. && $$ SYNOPSIS...JMG NEAR TERM...JMG/Lahiff SHORT TERM...Deal LONG TERM...Deal AVIATION...Lahiff is the U.S. government's official web portal to all federal, state and local government web resources and services.