Area Forecast Discussion
Issued by NWS Burlington, VT

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000 FXUS61 KBTV 041137 AFDBTV Area Forecast Discussion National Weather Service Burlington VT 637 AM EST Thu Mar 4 2021 .SYNOPSIS... Fair and seasonably cold weather expected today before mountain snow showers begin across the northern Adirondacks and northern Green Mountains tonight, continuing through Friday. A Winter Weather Advisory is in effect for portions of the northern New York and northern Vermont from 7 PM tonight until 7 PM Friday. On and off light snow showers or flurries likely continue in the northern mountains into this weekend before a trend toward milder weather occurs by next week. && .NEAR TERM /THROUGH FRIDAY/... As of 630 AM EST Thursday...Still some lingering cloud cover across the North Country despite drier air advecting in from the north. For such reasons, temperatures have remained steady. Slight adjustments were made to the hourly forecast temperatures to match trends in observations and also to account for non- diurnal trend given cold air advection. Otherwise, the going foreacast continues on track. Otherwise, a fair yet chilly day is in store with high temperatures only in the upper teens to low 20s. Conditions will become unsettled this evening as a large upper low begins to retrograde into eastern Canada due to blocking downstream. This will allow the pressure gradient to tighten as high pressure builds into the Great Lakes region. For such reasons, northwest winds will increase this afternoon becoming sustained at 10 to 20 mph. Winds will become gusty as well, especially along the eastern slopes of the Adirondacks and Green Mountains, with gusts up to 30 to 40 mph. Winds will continue at this magnitude through the overnight hours and into Friday afternoon before finally abating. Paired with cold temperatures, wind chills will be 10 to 20 below zero Friday morning. Increasing chances for mountain snow showers will begin this evening as well and continue into Friday due to a passing shortwave embedded in the northwest flow aloft. Snow will mainly be confined to the northern Adirondacks and the northern Green Mountains. Showers may be slow to begin, needing to initially overcome dry air at the surface. However, as moisture is advected in around the backside of the upper low, sufficient moisture will be present including within the snow growth zone. Snow ratios are therefore expected to be within the 20:1 to 30:1 range. Froude numbers look to be critical at the onset, allowing snow to fall mainly along the spine of the Green Mountains. Flow will then become blocked during the overnight hours, allowing snow to accumulate along and west of the western slopes. Mountain snow showers will begin to taper off during the morning hours on Friday, before a secondary pulse in the flow aloft produces an additional round of upslope snow beginning Friday afternoon. Overall, total snow accumulations between 7 PM tonight and 7 PM Friday will be 3 to 6 inches across the aforementioned locations, with 6 to 8 inches possible at elevations above 1000 ft. For such reasons, a Winter Weather Advisory is in effect. Due to the fluffy nature of the snow, blowing snow will also be a concern during this time. It`s important to note that with the second pulse of snow showers Friday afternoon and evening, flow will be supercritical and therefore is likely to occur downstream of the mountains as well. While there will be less moisture available with this round, model soundings indicate small amounts of instability with a well mixed boundary layer. Combined with the strong winds during this time, there is a non-zero threat for snow squalls Friday afternoon and evening, especially across northern New York where a weak surface boundary will be present. && .SHORT TERM /FRIDAY NIGHT THROUGH SATURDAY/... As of 442 AM EST Thursday...Light snow will come to an end Friday night though conditions will remain cold and blustery with continued strong northwesterly flow. Cloud cover will thin out overnight and minimum temperatures will drop into the single digits above and below zero, quite cold for early March. Additional upslope snow showers are anticipated for Saturday with northwesterly flow continuing, especially across the northern mountains. High temps on Saturday will be cold with temps only reaching the upper teens to lower 20s. This is over ten degrees below normal. && .LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/... As of 442 AM EST Thursday...Saturday night through early Monday will feature drier weather as a ridge of surface high pressure will drift across our area. Below normal temperature trend continues through that timeframe. A weak surface cold front crosses the region from Monday afternoon through early Tuesday morning, not a lot of forcing with this feature as parent low remains well north of the region. Drier weather returns for Tuesday afternoon through early Wednesday as surface high briefly ridges into our area from the south. Another low pressure system passes well to our north and brings next chance of precipitation to the region for Wednesday night into Thursday. Behind this system it looks like a bit of a pattern change is anticipated with much warmer temperatures for the tail end of the week. && .AVIATION /12Z THURSDAY THROUGH MONDAY/... Through 00Z Friday...Overcast skies remain across the North Country resulting in a mix of MVFR and low VFR cigs generally between 2500 to 6500 ft AGL. As skies continue to clear, a return to VFR conditions should be realized at all terminals wihthin a couple of hours. Dry conditions will persist throughout the day with winds out of the north at 5 to 10 knots until 18z. Thereafter, winds will increase to 10 to 15 knots with gusts up to 25 knots out of the west/northwest for the rest of the TAF period. A chance of snow exists after 00z Friday which may cause MVFR/IFR vis at KMSS, KBTV, and KSLK through the rest of the TAF period. Outlook... Friday: VFR. Chance SHSN. Friday Night: VFR. Slight chance SN. Saturday: Mainly VFR, with local MVFR possible. Slight chance SN. Saturday Night: VFR. NO SIG WX. Sunday: VFR. NO SIG WX. Sunday Night: VFR. NO SIG WX. Monday: VFR. NO SIG WX. && .BTV WATCHES/WARNINGS/ADVISORIES... VT...Winter Weather Advisory from 7 PM this evening to 7 PM EST Friday for VTZ002-006-016-017. NY...Winter Weather Advisory from 7 PM this evening to 7 PM EST Friday for NYZ030-031. && $$ SYNOPSIS...Hammond NEAR TERM...Hammond SHORT TERM...Neiles LONG TERM...Neiles AVIATION...Hammond is the U.S. government's official web portal to all federal, state and local government web resources and services.