059 FXUS61 KBGM 041500 AFDBGM Area Forecast Discussion National Weather Service Binghamton NY 1000 AM EST Wed Dec 4 2019 .SYNOPSIS... A trough of low pressure will move through today with some snow showers followed by a light lake effect snowfall on Thursday. A clipper system then tracks across NY with some light snow for those locations on Friday. High pressure builds in for the weekend. && .NEAR TERM /THROUGH THURSDAY/... 10 am update... Expanded the mention of light snow across the srn tier into ne PA and the Catskills quicker to the east than previously thought this morning. Forecast remains relatively unchanged with the short wave moving through this afternoon producing light scattered snow showers with some rain mixed in across the slightly warmer lower elevation areas, then changing back to snow and focusing se of Lake Ontario tonight in the form of lake effect snow showers. Adjusted snow amounts up just a few tenths of an inch. Still expecting around 1-3 inches across Oneida, Madison and Onondaga counties...maybe slipping into far srn Cayuga and nrn Cortland counties as well. Previous Discussion... With the sunrise update, slight adjustments were made based on the radar trends with the snow showers. Forecast discussion below on track. A trough of low pressure will move through the region today. The majority of moisture with this feature will not arrive till later today. Enough lift should be present with the moisture to develop scattered snow showers this afternoon and tonight across most of central NY. With northwest flow off of Lake Ontario, the snow showers should be enhanced in Onondaga, Madison and Oneida counties. Conditions appear favorable for organization of the snow showers into a band of snow showers tonight. Shear however looks to increase on Thursday which would turn these snow showers more cellular in the morning before the wind direction becomes unfavorable for lake snow by Thursday afternoon. Accumulations of snow look light through Thursday. Where the snow shower activity is more enhanced 1-3 inches of snow over through Thursday is anticipated with local amounts up to 5 inches. This forecast largely leaned on the RGEM which tends to preform well in Lake Effect events. Most spots further away from Lake Ontario will see an inch or less of snow. With precipitation not arriving till later in the day, most locations should rise above freezing with highs getting into the mid and upper 30's. Cloud cover tonight will keep lows in the 20's despite the snowpack in most of our NY counties. Thursday looks to be a couple of degrees cooler given the northwest flow, clouds will also likely linger through most of the day. && .SHORT TERM /THURSDAY NIGHT THROUGH FRIDAY NIGHT/... 325 AM Update... Main forecast issues will be an apparent clipper system moving through the region late Thursday night into Friday with a quick yet generally light coating of snow, followed by a window of lake effect into Friday night. Before the system, lingering lake effect Thursday evening will tend to dry up and/or shift mainly north of the Thruway as flow temporarily backs more west-southwesterly. Temperatures will dip in the 20s and then more-or-less hold steady as the low approaches. Non-GFS models have consolidated on the clipper system and its low tracking through the region early to mid Friday. The GFS also has it, but more of an open wave and with less moisture. For the non-GFS models, track of the center still has some variability; as far south as the NY-PA border or as far north as the NY Thruway corridor. Along and north of the track will have the best prospects for snow; probably 1-3 inches. To the south, including our PA counties to the Catskills, an inch or less is more probable. Indeed there may be very little for the Wyoming Valley to Poconos. That being said, soundings already show boundary layer instability as the cold front of the system moves through, and thus it could include a quick burst of gusty snow showers if moisture is adequate. We will need to assess localized squall potential as the time gets closer and more data becomes available; location of that potential will depend on where the low and thus the attached cold front end up tracking. Also, behind the front, northwesterly cold air advection will favor development of lake effect multibands for much of Central NY and at least flurries reaching into far northern PA. This could thus lead to additional fluffy accumulations. After highs of upper 20s-upper 30s Friday, temperatures will drop into the teens-near 20 for lows Friday night behind the system. && .LONG TERM /SATURDAY THROUGH TUESDAY/... 330 AM Update... A mostly quiet weekend will quickly give way to a busy pattern as we head into next week. Strong and cold high pressure will build into the area Saturday, with highs only in the 20s to near 30. Stratocumulus will likely remain trapped under a subsidence inversion for much of Central NY, yet that layer will be fairly thin and thus vulnerable to breaking up especially south of the Twin Tiers. Northeast PA to the Catskills may end up with a good amount of sunshine. The high passes directly overhead later Saturday, quickly getting us into southwesterly return flow for the remainder of the weekend. Temperatures will moderate in response, to highs of mid 30s-lower 40s Sunday and mostly 40s Monday. Sunday will still be dry, though thickening high clouds will be increasingly apparent aloft. The return flow eventually brings in enough moisture for precipitation as our next system approaches. Late Sunday night- early Monday could potentially be messy, with plenty of warm air aloft and thus if precipitation falls early enough it may include some freezing rain. That said, the high to our east will be well offshore; not anchored to our northeast which would be a more typical cold air damming/potential ice scenario. Thus we may end up going straight to plain rain into Monday for most of the area, with rising temperatures. Things look fairly wet perhaps even into Tuesday, with deep moist southwest flow. We will have to keep an eye on this, since getting a quick dose of combined rain and snowmelt could cause issues with rises in our rivers and streams. We will sort this out in coming days. && .AVIATION /15Z WEDNESDAY THROUGH SUNDAY/... Mainly MVFR ceilings are expected through the TAF period with some uncertainty at the exact levels close to fuel-alternates. KRME and KSYR have some potential for IFR ceilings and visibilities with more in the way pronounced snow shower activity after 20Z today. While a few brief VFR flurries or snow showers are possible till 20Z at all TAF, more concentrated snow showers with visibility restrictions should hold off till early evening. Westerly winds are expected to be under 10 knots. Outlook... Thursday...MVFR/IFR Restrictions likely at KRME and KSYR in lake effect snow showers. Light accumulations likely on runways. Mainly VFR elsewhere. Friday... MVFR/IFR restrictions with light snow at the NY terminals. Light accumulations possible on runways. A mix of rain and snow showers at KAVP. Saturday and Sunday...Mainly VFR. && .BGM WATCHES/WARNINGS/ADVISORIES... PA...None. NY...None. && $$ SYNOPSIS...MWG NEAR TERM...BJT/MWG SHORT TERM...MWG LONG TERM...MDP AVIATION...MWG