742 FXUS61 KBGM 070640 AFDBGM Area Forecast Discussion National Weather Service Binghamton NY 140 AM EST Tue Dec 7 2021 .SYNOPSIS... Winds out of the west continue to bring in chilly air, as well as lake effect snow showers east of Lakes Ontario and Erie. These will diminish to flurries by afternoon. A weak disturbance may bring some light snow to the area late tonight through Wednesday. Warmer yet eventually wetter weather will arrive Friday into Saturday. && .NEAR TERM /THROUGH TODAY/... 715 PM Update... Seeing some lake effect snow showers off of Lake Erie this evening and pushing east towards Steuben County. Increased snowfall chances here tonight and possible for 1 to 2 inches across the higher terrain in western Steuben County through tomorrow morning. Also, lowered snow ratios through the overnight hours as winds remain 40 to 50 knots throughout the DGZ until early Tuesday morning. This will likely limit snow ratios due to fracturing of ice crystals. Thus, have slightly lowered snowfall totals across Oneida and northern Onondaga County, but still should see at least advisory criteria in a few spots. Previous discussion... Behind the cold front, there will be isolated to scattered lake effect snow showers/flurries around across much of CNY and the far northern tier of PA. The two most concentrated areas of snow shower activity will be across the higher elevations of Western Steuben County, off of Lake Erie, and Lake Ontario. A dusting to half inch or so of snow is forecast for the higher elevations of CNY including western Steuben county. East of Lake Ontario, we have expanded the Winter Weather Advisory to include all of Oneida, Madison, and Onondaga counties. The mesoscale setup is becoming more favorable for a steadier lake effect band to develop. Around 1-2 UTC a weak 925mb trough develops just over Lake Ontario leading to decent 1000-850mb surface convergence east of Lake Ontario. Aloft at 850mb, temps should be around -8C which should be supportive of around 400-500 J/kg of lake induced Cape. With ample moisture in the 925-850mb level and mean westerly flow lake effect snow showers should develop and start producing light to moderate snow across northern Oneida County this evening. Guidance does show a multi lake connection from Huron on down to Ontario so the inland extent of the lake effect should be fairly decent. With the flow remaining fairly consistent initially, the band should be fairly stationary through around 06-08z. Around 06z, the 925mb trough passes just east of Lake Ontario and the winds start to become slightly more west-northwesterly. This should start to push the band slight to the south and west leading to lake effect accumulations across southern Oneida, Madison, and Onondaga counties. At this point, BUFkit soundings show quite a bit of lift in the DGZ and this is matched fairly well with plenty of surface convergence and modest theta-e lapse rates reaching into the Souther Tier. The multi-lake influence becomes stronger as the fetch over the waters lengthens at this point. Lake effect snow should likely push well inland just before day break although accumulations look to be less than half an inch south of the Thruway. The forecast challenge is that the band looks to be fairly will supported dynamically and should have the potential to produce inch to inch and a half an hour rates overnight. It is just a question of how long does the band setup over any given area. The lake effect should wind down and lift north of the area Tuesday afternoon. Outside of the lake effect Tuesday will feature seasonably cool temperatures, lighter west winds and partly sunny skies. Clouds do increase later in the afternoon out ahead of the next weather system. A weak high pressure at the surface builds in Tuesday night with lingering lake effect ceasing, though brisk southwesterly flow aloft will contain mid-to-high level clouds. Lows will be in the upper teens to mid 20s. && .SHORT TERM /TONIGHT THROUGH THURSDAY/... 330 PM Update... The chance for light snow continues Wednesday morning with a weak shortwave passing through as well as favorable jet dynamics being at the left exit region of a jet max at 300 mb. BUFKIT soundings sampled from across NEPA and CNY snow that the strongest lift will be outside of the dendritic growth zone so snow accumulations wont amount to much with an inch or less across most of the region with pockets of up to 2 inches in higher terrain. High pressure builds in late Wednesday into Wednesday night with CAA aloft dropping 850 mb temperatures down to -10C to -12C. Lake effect snow develops off Lake Ontario under the NW flow with northern Onondaga, northern Madison, and Oneida county having the best chance of seeing the snow. Snowfall is not expected to be much more than a few inches with dry air aloft and no multi lake connections to add extra low level moisture. The area of high pressure moves east of the region on Thursday with return flow setting up. Lake effect snow comes to an end as the winds aloft shift southwesterly. A warm front lifting into the region increases the cloud cover as well as the temperature aloft. With thick cloud cover and cold air in place, day time highs will still struggle to get above freezing even with the warm air moving in aloft. && .LONG TERM /THURSDAY NIGHT THROUGH MONDAY/... 330 PM Update... The long term stays active with SW flow aloft and several chances of precipitation. On Thursday night into Friday, the aforementioned warm front continues to advect northward with increasing chances of precipitation Thursday night into Friday with some isentropic lift. A strong ridge builds in late Friday into Saturday with much warmer temperatures advecting into the Northeast with well above average temperatures to start the weekend. Ensembles are in good agreement of a trough beginning to move in late Saturday into Sunday. With good agreement in the QPF fields between the NBM, GEFS, and EPS, PoPs have been kept near 80% for CNY (where the best agreement was) to near 50% in NEPA. The evolution of the surface low is uncertain with lots of uncertainty in location and strength so ptypes are unknown. Once the trough is to the east of us early next week, strong ridging builds back in with warming temperatures once again. && .AVIATION /07Z TUESDAY THROUGH SATURDAY/... Lake effect snow showers will visit KRME-KSYR this morning with intermittent IFR visibility; a few flakes reaching KELM briefly as well. Other than that, the cloud deck will be mainly in the 4-6 kft agl range for VFR conditions through 06Z Wednesday. West to west-northwest winds, initially gusting 20-25 knots for the NY terminals and 15-20 knots at KAVP, will slightly diminish during the day. This will coincide with lessening of lake effect snow showers as drier air overtakes the area. By this evening, wind will back to light west/southwest. Outlook... Late Tuesday night through Wednesday...Passing weak system with light snow and associated restrictions possible. Wednesday night through Thursday...Mainly VFR conditions. Thursday night...Brief chance of mixed precipitation and minor restrictions as a wave lifts through the region. Friday morning through evening...VFR. Late Friday night through Saturday...Rain/restrictions likely. && .BGM WATCHES/WARNINGS/ADVISORIES... PA...None. NY...Winter Weather Advisory until 3 PM EST this afternoon for NYZ009-018-036-037. && $$ SYNOPSIS...MDP NEAR TERM...MPK/MJM/RLD SHORT TERM...AJG LONG TERM...AJG AVIATION...MDP