Area Forecast Discussion
Issued by NWS Burlington, VT

Current Version | Previous Version | Text Only | Print | Product List | Glossary Off
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50
-- Highlight Changed Discussion --
-- Discussion containing changed information from previous version are highlighted. --
000 FXUS61 KBTV 080548 AFDBTV Area Forecast Discussion National Weather Service Burlington VT 1248 AM EST Fri Dec 8 2017 .SYNOPSIS...
-- Changed Discussion --
Lake effect snow will continue to impact parts of the Adirondacks and St. Lawrence Valley for today with some additional accumulating snowfall. Outside of the lake effect snow, it will remain mainly cloudy and chilly elsewhere. Although most areas will stay dry and cold over the weekend, a coastal storm may brush eastern areas with some light snowfall. A more widespread snowfall is expected during next week.
-- End Changed Discussion --
&& .NEAR TERM /UNTIL 7 PM THIS EVENING/...
-- Changed Discussion --
As of 1248 AM EST Friday...Made minor updates to the PoP grids based on current trends in the lake effect snow band that is currently just to the south of Saint Lawrence County. Radar imagery shows the band extending further east with light snow reaching the Champlain Valley near the Chittenden/Addison County border. Expect most of the light lake effect snow reaching Vermont to taper off in the next few hours. Temperatures are running a few degrees warmer based on cloud cover, so adjusted the temperatures to better match current conditions. Previous discussion below: The 3km HRRR and NAM both show this band to gradually shift back southward for most of the overnight, as the flow shifts thanks to the departing shortwave aloft. However, as the next piece of energy quickly approaches towards sunrise, the band may once again shift back northward in response to the changing low to mid level flow. Some additional snow showers are possible between sunrise and the mid morning hours on Friday across the northern Adirondacks as the band continues to slide back northward, with an additional light accumulation in some areas. Meanwhile, some additional light snow showers and flurries are ongoing across the remainder of the Adirondacks and into parts of the central and northern Greens, especially in upslope favored areas. This snowfall won`t amount to much, but an additional coating cannot be ruled out. Most of this should through the evening hours, as some drier air should be moving in for later tonight. Otherwise, skies will remain mostly cloudy, although some breaks are possible by later tonight, especially for larger valley areas. Overnight lows will generally be in the mid 20s to low 30s, although some teens will occur for the higher elevations. The lake-effect band should lift towards the St. Lawrence Valley on Friday mid to late morning, but then will be weakening and diminishing through the day, as the flow will start to become too southerly. Any accumulation looks rather minor for northern St. Lawrence County through the day. Elsewhere, most areas will be partly to mostly sunny on Friday and dry, although it will continue to be seasonably chilly with highs in the mid 20s to mid 30s.
-- End Changed Discussion --
&& .SHORT TERM /7 PM THIS EVENING THROUGH 6 PM SATURDAY/... As of 400 PM EST Thursday...Lake effect snow will finally diminish by Friday evening, as the mixed layer flow becomes more S-SW due to an amplifying flow pattern. There could be a few leftover snow showers in the St. Lawrence Valley during the evening, but should end by midnight. Tranquil conditions expected late Friday night into Saturday morning, as a small area of high pressure settles in across the region. Saturday will start out dry, but there will be increasing chances for light snow by later in the day, especially across the eastern half of VT. The upper level flow pattern is forecast to amplify as a trough dives southeast across the central Great Lakes and Ohio Valley region, with downstream ridging off the southeast U.S. coast. An area of low pressure is expected to develop along a baroclinic zone near the eastern seaboard. Precip will spread northward through the day, and may reach eastern VT just before sunset. Model guidance has trended north and west with the position of the baroclinic zone and surface cyclone, especially the ECMWF and NAM, which are favored solutions by WPC at this time. So there could be a dusting before by sunset Saturday, mainly from the western slopes of the Greens eastward. Temps may reach the lower to mid 30s in valleys during the afternoon before any snow commences. There now appears to be a somewhat better chance for light snow, especially across VT Saturday night. The aforementioned surface cyclone is forecast to deepen rapidly east of New England during this time, with snow wrapping around the low farther back to the north and west into VT. Will need to continue to watch model forecast trends, since the heaviest axis of QPF will not be too far away over eastern New England. The more western track is a result of a more amplified pattern. If even stronger downstream ridging develops, this would result in an even more westerly track. && .LONG TERM /SATURDAY NIGHT THROUGH THURSDAY/... As of 400 PM EST Thursday...It will feel like winter through the upcoming week. A cold and potentially stormy pattern may be setting up during this time, with the probability for accumulating snow increasing by early to mid next week. By Sunday, the coastal storm will be well north and east of the region, but an upper level trough will remain over northern NY and VT. So this will result in a continued chance of snow showers. Temperatures are forecast to be slightly below normal, with highs mainly in the mid 20s to lower 30s. Another short wave trough will be approaching from the upper Great Lakes Sunday night. Ahead of this system, low level winds will back to a SW direction in response to the approaching trough. This will result in the potential for some lake effect snow in parts of the St. Lawrence Valley and NW Adirondacks. It appears light accumulations would occur though, as the upper trough moves through by Monday and shifts the winds to more of a westerly trajectory. Will continue to mention chances for snow showers associated with the trough passage on Monday. Then, attention shifts to another potential coastal storm that may impact the region Tuesday into Wednesday. The ECMWF is indicating a developing cyclone just south of Cape Cod on Tuesday, then rapidly intensifying Tuesday night as it potentially tracks into the Gulf of Maine. A deep upper trough over the lower Great Lakes may close off in the mid levels over SE New England by Wednesday. This could result in a prolonged snow event depending on the evolution/track of the system. The GFS is also depicting a developing storm, but farther west due to a shallower upstream upper level trough with strong isentropic lift in northern NY/VT. So despite the model spread, there is a signal for possible widespread accumulating snow during the time. Colder and breezy conditions expected Wednesday night into Thursday, behind the departing storm. Again, snow showers cannot be ruled out in the cold/cyclonic flow regime. && .AVIATION /06Z FRIDAY THROUGH TUESDAY/... Through 00Z Saturday...Lake effect snow band impacting SLK, PBG and BTV currently. SLK has IFR conditions, while other sites are remaining VFR. Skies will be BKN-OVC at 3500-5000 ft with VFR conditions and SW winds around 5-10 kts. A few higher gusts are possible for the higher elevations. Overnight, lake-effect should gradually meander away from SLK, although there could be some additional snow showers there towards daybreak Friday. By mid-morning Friday, VFR conditions are expected through the day for all sites, with sct-bkn cigs around 4-5 kft. Southwest winds will increase during daytime mixing to around 5-10 kts with some higher gusts at times, especially over the higher terrain and within the St. Lawrence Valley. Outlook... Friday: VFR. Slight chance SHSN. Friday Night: VFR. NO SIG WX. Saturday: VFR. NO SIG WX. Saturday Night: VFR. Slight chance SHSN. Sunday: Mainly VFR, with local MVFR possible. Chance SHSN. Sunday Night: Mainly VFR, with areas MVFR possible. Chance SHSN. Monday: Mainly VFR, with areas MVFR possible. Slight chance SHSN. && .BTV WATCHES/WARNINGS/ADVISORIES...
-- Changed Discussion --
VT...None. NY...Lake Effect Snow Warning until 7 AM EST this morning for NYZ029-087. Winter Weather Advisory until 7 AM EST this morning for NYZ030.
-- End Changed Discussion --
&& $$ SYNOPSIS...Taber NEAR TERM...Evenson/RSD/NWS ALY SHORT TERM...RSD LONG TERM...Deal AVIATION...Neiles

USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.