231 FXUS61 KBGM 180241 AFDBGM Area Forecast Discussion National Weather Service Binghamton NY 941 PM EST Wed Jan 17 2024 .SYNOPSIS... Cold and quiet weather tonight will be followed by a clipper system Thursday. Light snow will be possible across most of the region. Another system passes through late Thursday night into Friday with additional snow accumulations, which may impact the Friday morning commute. Lake effect snow showers are then expected mainly in Central New York through the weekend. && .NEAR TERM /THROUGH THURSDAY NIGHT/... 940 PM Update... Sheltered valleys with an existing coating of snow indeed radiated very well so far this evening in this very dry air, even with stout southwest flow within the boundary layer. Several low elevation spots east of I-81 dropped quickly into the single digits, including 2 degrees in Deposit on the NY Mesonet, and 7 degrees in Shohola of Pike County PA. That said, clouds will increase and temperatures will begin to rebound; indeed it has already have started. Norwich for example was down to 3 degrees but now 7. Earlier this evening, adjustments were made to allow a bit more of that radiational cooling in sheltered valleys. Boundary layer dewpoints were running 2 to 8 degrees below zero which also aided in more radiational cooling. Forecast was adjusted to also further increase snow chances some more on Thursday. It appears to be a high chance/low amounts scenario, with only weak lift from the shortwave yet also saturated dendritic growth layer which should easily manage to yield some flakes. Went ahead with likely light snow wording from Ithaca- Cortland- Binghamton east to Norwich-Oneonta- Delhi. Half inch to inch of fluff appears probable for those areas; perhaps even inch-and-a- half in Delaware County. Higher terrain of Susquehanna-Wayne in PA could also squeeze an inch. Confidence is increasing that the next stronger clipper will be ill-timed for impacting the morning commute with snow Friday. Model soundings show an impressively thick dendritic growth layer, nearly isothermal at perfect flake-producing temperatures, dominating most of the lowest 12 kft agl. I went in and even further quickened the onset to really ramp up the likelihood west-to-east between 3-7 AM Friday. Previous discussion... Tonight will be quiet and cold, though slightly warmer than last night as warmer air drifts in from the south. Still, lows tonight will be in the single digits and low teens. Blustery conditions will keep wind chills near or below zero. This update did go slightly below guidance by blending in some of the NBM tenth percentile temperatures as skies will remain mostly clear through the much of the overnight hours. Lake effect snow also continues tonight with up to an inch possible for N. Oneida. A weak clipper system will move through the region Thursday. This system will bring light snow across most of the region, though the Twin Tiers will be most favored. Drier air moves in from the south, so lesser amounts are expected across the Wyoming Valley and Poconos. Cold conditions will favor a drier snow with SLRs around 20:1. Snowfall totals with this system will generally be an inch or less. Models have a small bullseye of higher QPF amounts over the eastern portions of the Twin Tiers and into portions of the Western Catskills. This area will likely see higher amounts, but totals are expected to be less than two inches. Temperatures will max out in the 20s but winds will remain gusty, so it will feel more like the teens. Thursday night will start out quiet though there could be some lingering snow that clips N. Oneida. Otherwise, another clipper system will move in from the west after midnight with another round of snow. Prior to sunrise, a quick dusting of up to a half inch will be possible. Most of the snow from this system will fall beyond this period. With widepsread cloud cover and slightly warmer air drifting northward, temps will only fall into the teens and low 20s. Winds become light so wind chills will be only a couple degrees lower than temperatures. && .SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/... 340 PM Update... A surface low moves east through the mid Atlantic states and off the coast Thursday night into Friday. This is being pushed quickly east by a cut off upper level low and multiple short waves dropping south into the trough through the Midwest then through our area Friday night. This will be a widespread light overrunning snow during the day Friday. 1 to 3 inches of snow is likely. Highs will be in the 20s. Friday night to Saturday night snow showers will be mostly over CNY. Cold air advection will be in full swing setting off the lake effect machine. 850mb temperatures fall to -20C. Northwest winds Saturday will be 15 to 25 mph with higher gusts. The wind will make it feel even colder with the highs in the teens. For most of the time low level winds will be out of the N or NNW taking Lake Huron out of the game. The Finger Lakes like the north wind though which could send narrow bands of snow showers into NEPA. Lows Saturday night will be in the single digits to around 10 above. && .LONG TERM /SUNDAY THROUGH WEDNESDAY/... 340 PM Update... Ridging builds into the area Sunday and Monday. This will shut off the lake effect snow showers in central NY Sunday. As the flow shifts to westerly, warmer air will move into the entire period. Upper level ridging will set up as a trough will be over the Rockies. High temperatures go from the 20s on Sunday to the 30s on Monday then to the upper 30s and lower 40s Wednesday. Lows go from around 10 Sunday night to the 30s Wednesday night. Weak waves move northeast into the area with precipitation starting Monday night in CNY and Tuesday in NEPA. Chances of precipitation continue through Wednesday. Precip type starts as snow but transitions to a mix then to mostly rain Wednesday afternoon as warmer air moves in. && .AVIATION /03Z THURSDAY THROUGH MONDAY/... 00Z Update... Quiet conditions will persist overnight with VFR, as initially mainly clear sky gives way to an incoming deck mostly at several thousand feet AGL. However, a weak clipper system will cause most if not all of the NY terminals to experience some light snow midday into afternoon, with MVFR ceilings and/or visibility; likely IFR visibility at times for KBGM-KITH. Uncertainty exists for whether KSYR-KRME could also hit IFR visibility despite very light snow amounts; not in TAFs yet but if confidence increases it may be added. KAVP is forecast to stay VFR for the duration of the clipper, but there is a small chance that brief snow/MVFR could reach that far. Winds throughout this period will be primarily out of the southwest 6-10 knots; a few gusts into mid teens knots. Outlook... Thursday night through Friday...Restrictions expected as stronger clipper system brings widespread snow. 1-2 mile visibility likely as system passes. Friday night through Saturday...Lake effect snow showers and associated intermittent restrictions for KSYR-KRME-KITH-KBGM; possibly even KELM at times. Gusty NW winds areawide. Saturday night through Sunday...Lake effect snow showers- flurries and associated restrictions may linger for at least KSYR and possibly KITH-KRME at times. Monday...Mainly VFR. && .BGM WATCHES/WARNINGS/ADVISORIES... PA...None. NY...None. && $$ SYNOPSIS...BTL/MDP NEAR TERM...BTL/MDP SHORT TERM...TAC LONG TERM...TAC AVIATION...MDP