499 FXUS61 KBGM 082315 AFDBGM Area Forecast Discussion National Weather Service Binghamton NY 615 PM EST Sun Dec 8 2019 .SYNOPSIS... A large storm moving thorough the Great Lakes will push warm air and rain into the area Monday and Monday night. Colder air will follow the storm on Tuesday bring snow showers that will linger into early Wednesday. && .NEAR TERM /THROUGH MONDAY NIGHT/... Lee wave develops rapidly into a lake runner passing well west of the area. Rapid deepening develops along with a nice jet streak with the forecast area being in the favorable entrance region. So precipitation explodes over the area Monday as the low races up into Quebec. Very cold last night with a good snow cover could keep road temps very cold and allow for a bit of freezing rain tonight, mainly over the extreme northern CWA despite the strong warm advection. No large blocking high keeping the cold air locked as the rain moves so expect a pretty quick warm up. Not anticipating the need for an Advisory at this time, but it could be handled with an SPS. Rapid movement of the system will limit rainfall amounts but snow melt with the rain will bring rises below caution stage. A couple of spots could exceed that or come close, namely the Black river in Boonville and some headwater points on the Upper Susquehanna and Delaware. Hydro watches should not be needed. Rain will become more showery ahead of he cold front Monday night as a dry slot develops along with the upper jet structure pulls out to the north. && .SHORT TERM /TUESDAY THROUGH WEDNESDAY/... 300 PM Update...No major changes to the short term period. Cold front still rather slowly sags through the area during the day Tuesday, with gradually falling temperatures in central NY by midday or early afternoon. Temperatures begin to fall by late afternoon across NE PA. Before the front moves through it will be another very mild day, with highs 45-50 in CNY, and 50-55 for NE PA. Temperatures fall into the 30s by sunset across CNY, but still 40-45 for NE PA. Rainfall amounts look light on Tuesday, generally under a quarter inch. Some wet snow could mix in across the hilltops of CNY late in the day. WSW winds become NW by afternoon; 6-12 mph with gusts to around 20 mph. Tuesday Night: The mid level front stalls along just southeast of our forecast area Tuesday night. Cold air continues to filter in from the NW during the evening and overnight. This creates a bit of an anafront situation, as another weak wave rides up along the boundary from the south. Latest guidance is still struggling with just how much and how far to the NW precipitation will redevelop Tuesday night. Used a blend of the latest guidance for now. As cold air advection continues, temperatures should be cold enough to change the lingering precipitation over to snow by the late evening hours (even across NE PA). Again, still plenty of uncertainty but chances are increasing for at least some accumulating snow (perhaps 1-3") mainly southeast of Binghamton, across NE PA and the southern Catskills especially. Will continue to monitor the latest trends on this scenario closely. At the same time, as the cold air deepens lake effect snow shower will also develop along and north of the NY Thruway near Syracuse and Rome. Some minor snow accumulations are also possible up here. Overnight lows will be in the 20s. Wednesday: The slow moving front should finally completely exit the area off to the south and east in the morning. 850mb temperatures fall to around -12C through the day. Along with the cold there will be a breezy west wind and more lake effect snow showers. A weak clipper system passed by well to the north across Ontario, but this will likely act to shift the lake effect snowbands around from south to north through the day. High temperatures only manage to reach the mid-20s to lower 30s. && .LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/... 310 PM Update...No major changes to the extended either with this update. Lake effect snow showers continue Wednesday night and early Thursday before high pressure builds over the region. Dry weather late Thursday through much of Friday. Still watching a system approaching from the south along the coast Friday night into Saturday. High pressure slides off the coast prior to this system arriving, bringing a warm south-southeast flow. Trended the weather grids toward more rain with this system, with warmer temperatures expected aloft and at the surface. Previous Discussion Below 345 AM Update... Very cold conditions are anticipated Wednesday through Thursday, with lake effect snow showers for some parts of the area, followed by moderating temperatures as we head into the weekend. Arctic air mass will take over Wednesday and especially Wednesday night-Thursday as the Canadian high builds over the area. Boundary layer flow ahead of the high will be westerly or perhaps even west-southwest at times, which will tend to direct heavier lake effect snows mainly north of the area Wednesday morning through evening. That said, clusters of Lake Erie snow showers and flurries can still be anticipated for much of the area, especially Central New York. Westerly winds will gust 15-25 mph Wednesday with highs of mid 20s to lower 30s. Later Wednesday night into early Thursday, subsidence inversion of incoming high will begin to lower yet the dendritic growth zone will also be contained underneath it. As low level flow veers a bit more northwesterly ahead of the high, lake effect off of Lake Ontario may advance across the NY Thruway late Wednesday night, with at least light multibands pressing further southeast Thursday morning. Lows will be in the upper single digits to upper teens. The high pressure and its very dry air eventually win out, ending lingering flurries by afternoon and allowing for at least some sunshine. Highs Thursday are expected to be only 20s areawide. However, we will get into return flow as that high passes by, with moderating temperatures Friday-Saturday. Friday appears dry, but there is plenty of uncertainty during the first half of the weekend as an upper trough digs to our west, and advects in moisture and thus possible precipitation. This may include a snow to mix to rain transition. && .AVIATION /00Z MONDAY THROUGH FRIDAY/... VFR expected through the night. Only aviation concern remains the LLWS as southeast winds at the surface are topped just above the boundary layer with a strong southwest wind developing ahead of the approaching trough. Lowered ceilings and visibilities will develop late tonight after about 11Z and on into the day Monday as rain moves into the area. Conditions will eventually become IFR as the rain becomes heavier through the rest of the morning. The heavier rain shifts to the east Monday afternoon and the rain becomes more scattered. The threat for MVFR fog will likely increase through the afternoon as the near- sfc layer becomes saturated. Ceilings may also drop to IFR or lower. LLWS will likely continue through the day tomorrow as a secondary push of 50 kt winds around 2-3k ft arrives after 19Z. Outlook... Monday night into Tuesday...Restrictions likely in rain. Wednesday...Restrictions possible in snow showers. Thursday and Friday...VFR expected. && .BGM WATCHES/WARNINGS/ADVISORIES... PA...None. NY...None. && $$ SYNOPSIS...DGM NEAR TERM...DGM SHORT TERM...MJM/MDP LONG TERM...MJM/MDP AVIATION...BJT/DGM