Area Forecast Discussion
Issued by NWS Burlington, VT

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000 FXUS61 KBTV 181446 AFDBTV Area Forecast Discussion National Weather Service Burlington VT 946 AM EST Sat Jan 18 2020 .SYNOPSIS... After one last very cold morning, temperatures will begin to warm today as a low pressure system approaches from the southwest. The system will send a warm front through later today, resulting in widespread snowfall over the region. The heaviest snow will fall late this evening into the first part of tonight, before tapering off through the day Sunday. Snowfall amounts will be between 3-7 inches with locally higher amounts across high terrain. Quieter weather with below normal temperatures is expected for the first half of next week. && .NEAR TERM /THROUGH TONIGHT/... As of 940 AM EST Saturday...Winter Weather Advisories remain in effect for the entire forecast area, valid from 1 PM this afternoon to 4 PM Sunday. No significant changes were needed with this update. Chilly conditions continue this morning, with most locations still in the positive/negative single digits. Cloud cover will only continue to thicken, so don`t anticipate much sunshine today, which will temper any warming. Radar is showing light returns spreading over northern NY, but surface observations indicate the precipitation is still well to our west, in the Buffalo area. Therefore, still anticipate snow will hold off until mid- late afternoon for much of our region. The forecast has this all pretty much covered, so just made some very slight tweaks to PoPs and temps to match the latest radar/observation trends. Overall the forecast remains on track. Previous discussion...Cold start to the weekend this morning with temperatures starting out near or below zero for much of the area. Morning satellite imagery shows high clouds streaming into the area ahead of a developing low over the central US. High temperatures today will be slow to warm under the thickening blanket of clouds, despite developing southerly flow over the region as the low approaches from the west. Have knocked down forecast highs for the day today, with readings now expected to top out in the mid to upper teens across most of the area. The approaching low will track to the Great Lakes Region this afternoon, pushing a warm front northeastward through our forecast area as the center of the low tracks to our north and west. Warm air advection driven snow will start as the boundary moves through, with snow start times ranging from 2-4 PM this afternoon in northern NY to 4-6 PM this afternoon in VT. Progged 925 to 950 mb fgen (mainly over northern NY) as the initial warm front moves through does support the potential for a heavier band (or bands) of snow, especially this evening/early overnight when upper-level support will line up with best lower- level circulation. Any bands that do form could contain some heavier snow and low visibilities. BUFkit soundings show that best omega and RH is not necessarily lined up within DGZ, so not expecting snowfall rates to be overly impressive at this time. After the initial warm front pushes through, forcing for ascent decreases and snowfall rates will lessen for the remainder of Sunday night. The center of the low will ride up the Saint Lawrence Valley early Sunday morning, allowing strong southerly flow to veer to the west. At this point, expecting snow to become more tied to terrain, with downsloping hole emerging the Champlain Valley and continued upslope snow over the northwestern Adirondacks and the northern Greens. This pattern will continue through the day Sunday, with little additional accumulations expected in valley locations but another few inches over higher terrain during the day. All said and done, total snow accumulations will range from 3-7 inches, locally higher in higher terrain. The Champlain Valley will see the lowest accumulations, while the northern Adirondacks and northern Greens will see the highest. In addition to snow, the low will bring some gusty winds to the area. A 50+ kt southerly low-level jet will move overhead this evening. Given the strong inversion resulting from the warm air advection just off the surface, mixing will be minimal and the vast majority of the momentum aloft will not be transferred to the surface. However, there will be some briefly gusty (15 to 25 mph) winds this evening, especially over higher terrain and channeled up the Champlain Valley. && .SHORT TERM /SUNDAY THROUGH SUNDAY NIGHT/... As of 303 AM EST Saturday...Evening snow showers then wane and end overnight Sunday as eastward extension of polar high pressure across the Northern Plains settles across the region. Still some lingering clouds, but a trend toward partly cloudy conditions by sunrise Monday still appears reasonable at this point. Low temperatures near seasonable mid-winter norms in the single digits. Then partly cloudy and quiet on Monday as aforementioned high pressure continues to build slowly east. High temperatures seasonably cold in the teens to locally near 20 in broader southern valleys. && .LONG TERM /MONDAY THROUGH FRIDAY/... As of 303 AM EST Saturday...A welcome break in active weather then looks to continue for most of the work week as high pressure becomes anchored across the Mid-Atlantic/Northeast. A glancing blow by another polar front Monday night may spark a few northern mountain flurries, otherwise partly cloudy skies and dry weather are expected over the 5 day period with a gradual warming trend. Highs on Tuesday similar to Monday in the teens, then 20s for Tuesday and 30s from Wednesday onward as modified air of Pacific origin bridges across the CONUS. Some suggestion that another system may affect the region toward next weekend but confidence is low at this point with a broad lack of consensus among medium range guidance so just lower end chance pops will be offered by next Saturday. && .AVIATION /15Z SATURDAY THROUGH WEDNESDAY/... Through 12Z Sunday...High and mid clouds will continue to spread over the forecast area, thickening and lowering through the TAF period. Expect all TAF sites to remain VFR through 18Z. Snow will spread northeastward from NY through VT after 18Z, accompanied by reduced visibilities and ceilings to the MVFR/IFR range. Some localized LIFR conditions are possible after 00Z, especially at KSLK and KRUT where bands of snow will form and snowfall will be heaviest. Light and variable winds this morning will become south/southeast this afternoon at 6-12 kts. Have included mention of LLWS at most TAF sites this evening as southwesterly jet moves in aloft. In addition to LLWS, areas of turbulence can be expected. Outlook... Sunday: Mainly MVFR, with areas VFR possible. Chance SHSN, Areas BS. Sunday Night: Mainly VFR, with areas MVFR possible. Chance SHSN. Martin Luther King Jr Day: VFR. NO SIG WX. Monday Night: VFR. NO SIG WX. Tuesday: VFR. NO SIG WX. Tuesday Night: Mainly MVFR, with areas VFR possible. NO SIG WX. Wednesday: Mainly VFR, with areas MVFR possible. NO SIG WX. && .BTV WATCHES/WARNINGS/ADVISORIES... VT...Winter Weather Advisory from 1 PM this afternoon to 4 PM EST Sunday for VTZ001>012-016>019. NY...Winter Weather Advisory from 1 PM this afternoon to 4 PM EST Sunday for NYZ026>031-034-035-087. && $$ SYNOPSIS...Duell NEAR TERM...Duell/Hastings SHORT TERM...JMG LONG TERM...JMG AVIATION...Duell is the U.S. government's official web portal to all federal, state and local government web resources and services.