095 FXUS61 KBGM 081749 AFDBGM Area Forecast Discussion National Weather Service Binghamton NY 1249 PM EST Mon Jan 8 2018 .SYNOPSIS... Low pressure moving through eastern Canada will bring some light snow to the region through this afternoon. Most areas will only see an inch or less of snowfall but northern sections of central New York will receive several inches of snowfall especially in Oneida County. Overnight behind the surface trough lake effect snow showers will continue southeast of Lake Ontario. This activity will diminish by midday Tuesday. The pattern becomes more active and warmer mid week through late week with additional chances for mixed precipitation and eventually all rain. && .NEAR TERM /THROUGH TUESDAY/... 1030 AM update...Near term forecast remains on track. Snow is having a difficult time overcoming large dewpoint depressions for much of the area. Therefore, believe the current snowfall forecast totals of generally under 1 inch for NE PA and the NY Southern Tier looks good. Still expecting 1-2 inches, with localized 3 inch amounts from S. Cayuga---Cortland---Chenango and Delaware counties northeast. Except Oneida county where a winter weather advisory remains in effect. A good SSW upslope flow will enhance snow amounts here, especially northern Oneida county. In fact, bumped up total snow amounts here slightly, and am now expecting high end advisory amounts of mainly 6-9 inches, but locally around 10 inches by Tuesday morning in Northern Oneida. Along the NY Thruway corridor in Oneida County, look for a general 3-6 inches by Tuesday AM. The heaviest period of snow is moving through our eastern CWA now, and will continue into the early afternoon hours before shifting east. Snowfall rates may occasionally reach 1"/hr in Oneida County into the early afternoon hours. Once this main batch of synoptic moisture moves east later this afternoon, expect just scattered snow showers around the region...except an area of locally steadier snow will persist over the favored upslope region in Oneida County. As 850mb temperatures drop later this evening/tonight and the flow aligns between 280-300, a band of lake effect snow will develop over the northern half of Onondaga, Madison and central Oneida County. This should bring another 1-3 inches of snow in this area. The rest of CNY will only see flurries and scattered snow showers tonight, with less than 1 inch of accumulation. NE PA will just see scattered flurries, with little if any accumulation tonight. High pressure over the mid Atlantic region and a surface trough moving through the central Great Lakes is producing a southwest flow of moderating air across the region. Radar returns over the northern forecast area are beginning to intensify as isentropic lift increases. So far not much reported at the surface as low level are very dry with dew point depressions 15-20 degrees. Models remain consistent with indicating the better isentropic forcing will reside in the northern forecast area with a precipitation shadow over much of the southern tier and Finger Lakes region. Initially this morning light snow will develop over the northern areas with enhanced upslope in northern Oneida County. Later this morning through afternoon as the surface trough moves through the entire area will see a brief period of light snow. Temperatures in the lake plain have already reached the lower 30s but some dew point cooling is expected once the activity becomes more significant. High temperatures will range from the upper 20s to middle 30s. Tonight, most areas will be precipitation free but southeast of Lake Ontario lake effect snow showers are likely with a 300 degree steering flow developing by late tonight. Airmass not very cold so activity not expected to be that intense. Total snow accumulation in Oneida County where an advisory is in effect will range from 4 to 9 inches with the highest amounts expected over northern Oneida County. On Tuesday high pressure will build in from the Ohio Valley and end the lake effect snow showers around midday. Highs will generally range in the lower to middle 30s. && .SHORT TERM /TUESDAY NIGHT THROUGH WEDNESDAY NIGHT/... A surface high pressure system will build over the CWA Tuesday night, and this should help to completely shut off any lingering lake effect flurries after midnight. There could however be some lingering lake effect clouds through the night, mainly over the northern Finger Lakes. Outside of these lake effect clouds/flurries there will be good raditional cooling conditions, and overnight lows will dip into the teens areawide. 330 PM Update...A rather complex long term forecast, with several systems bringing a multitude of concerns to the area. First off, models are still struggling in handling a shot of weak warm air advection precipitation Wednesday afternoon and evening. The latest GFS/NAM are quite wet, bringing a tenth or two of precipitation to the area during this time...meanwhile the CMC/ECMWF are much drier with this wave...only bringing a few hundredths at best; mainly north. For now took a blend of these solutions, which did allow some likely PoPs over Central NY late Wednesday and Wednesday evening. The main concern with this system will be precipitation type. Although precip amounts are looking light, models are in decent agreement that temperatures aloft will be warming rapidly, to between +2 to +6C at 850mb...and model soundings indicate a chance for freezing rain or sleet for much of the area as surface temps remain locked in the upper 20s to lower 30s Weds evening. Surface dewpoints will be low (20s), which will allow surface temps to wet bulb out as precip moves in. Eventually surface temps will gradually warm above freezing from west to east later Wednesday night, with a non diurnal temperature trend expected. && .LONG TERM /THURSDAY THROUGH SUNDAY/... Thursday looks showery, with much warmer temperatures. Precipitation type should be all rain, as highs reach the mid- 40s to lower 50s areawide. Latest model guidance is in good agreement that a period of steady or perhaps even heavy rain will move through the area Thursday night into Friday especially the eastern 2/3 rds of the CWA. PWATS rise above 1" and surface dewpoints rise into the lower 40s under a strong southerly flow. Temperatures remain very mild Thursday night and Friday, holding in the 40s to around 50 south. The combination of rain, high dewpoints and warm temperatures may allow area streams and rivers to rise, breaking up the thick ice coverage that currently exist. Therefore, area streams and rivers will need to be monitored very closely during this time for rises, and potential ice jam issues. Significant model disagreement remains later Friday into Saturday. The 12z GFs remains somewhat an outlier, bringing strong low level cold air advection as early as Friday afternoon over the Finger Lakes, and North-central NY. The GFS would bring a much colder scenario, with a wintry mix changing to snow from NW to SE, late Friday into Saturday. Meanwhile, the latest CMC and ECMWF are holding steady, insisting that a strong area of low pressure will pass by to our west Friday night-Saturday AM, leaving us in the warm sector, with more rain. All models are in agreement that a strong cold will have pushed through the area by Saturday evening....bringing much colder weather by Saturday night and next Sunday. With the renewal of the cold air, there will also be a chance of snow showers during this time. Considering the significant differences in the model guidance Friday into Saturday, used a blend of all available guidance for the official forecast during this time...and will continue to adjust as model trends become clearer in the coming days. && .AVIATION /18Z MONDAY THROUGH SATURDAY/... Periods of snow will occur continue at KRME terminal this afternoon with primarily IFR conditions. Alternate required restrictions are likely through late tonight when lake effect snow showers bring IFR conditions after 06Z. At KSYR, generally VFR or MVFR conditions are expected for the rest of today and into this evening. Then, a lake effect snow band will bring IFR conditions for a time, mainly between 09/06-12Z tonight. Conditions should improve at KSYR after about 09/14z as the band shifts south and weakens. The southern NY terminals will see less restrictive conditions will primarily VFR or MVFR this afternoon and evening. Later this evening and into tonight, as the flow shifts more out of the NW, additional shsn and lower CIGS could impact KBGM and KITh, bringing possible IFR conditions. These IFR conditions will likely linger into Tuesday morning here. At KAVP, a period of snow and sleet will impact the terminal over the next 2 hours or so. This precipitation will then move east, away from the area. After this, expect mainly VFR or high end MVFR conditions into the evening. Late tonight, as winds shift more west or WNW, some lower CIGS and brief -shsn could impact the terminal...bringing occasional alternate MVFR conditions. Outlook... Tuesday afternoon...Possible restrictions from lake effect snow showers, mainly KSYR-KRME. Wednesday...Mainly VFR expected. Wednesday night...Possible restrictions in a wintry mix. Thursday and Friday...Restrictions in light rain showers. && .BGM WATCHES/WARNINGS/ADVISORIES... PA...None. NY...Winter Weather Advisory until 7 AM EST Tuesday for NYZ009-037. && $$ SYNOPSIS...MJM/RRM NEAR TERM...MJM/RRM SHORT TERM...MDP LONG TERM...MJM/MDP AVIATION...MJM/RRM