440 FXUS61 KBGM 162351 AFDBGM Area Forecast Discussion National Weather Service Binghamton NY 651 PM EST Mon Dec 16 2019 .SYNOPSIS... A low pressure system will bring snow and a wintry mix to the area tonight into Tuesday as it slides through the Mid- Atlantic region. Temperatures turn much colder with numerous snow showers and possible snow squalls on Wednesday as an arctic cold front moves through. && .NEAR TERM /THROUGH TUESDAY/... FGEN forcing moving from central PA into the Poconos this evening with potential for a burst of moderate to heavy snow late this evening into the overnight. This forcing then lifts northeast into portions of the Catskills. However, some indications do show a warm layer coming into these areas leading to precipitation changing to sleet and freezing rain overnight. Dewpoints are currently lower than modeled across the region, so this along with heavier precipitation rates should bring some cooling to offset an advancing warm layer for a good portion of the night. As a result, mainly snow is still expected regionwide till well after midnight. Sky cover was also increased to account for the high clouds ahead of the storm. Previous summary below of forecast.... Overrunning with warm air advection precipitation overspreads the region from south to north tonight through the overnight hours. Thermal profiles should be cold enough at the onset of precipitation tonight for it to begin as all snow. Snowfall rates may become fairly intense at times across NE PA with strong 850 to 700mb frontogenesis developing from 03Z to 12Z Tuesday. Steady snow arrives across NE PA around or just after 0Z tonight, reaching the Twin Tiers around or just after midnight. The most intense snowfall rates should occur between the window of 03Z to about 09Z across the Poconos region. A quick 4 to 5 inches of snow will be possible and some localized amounts above 6" will be possible. A changeover to sleet and freezing rain occurs Tuesday morning with icing amounts possibly up to a quarter of an inch in the higher elevations of the Poconos region and lesser amounts elsewhere. How far north the mixing line will make it is still uncertain, but thinking we will see some freezing rain to at least the Southern Tier of NY. Tuesday: Main changes from the previous forecast is that the QPF amounts and snowfall amounts across NE PA have trended higher with the 12Z model guidance. Also, brought freezing rain line further north into Central NY, as dry slot pushes in late Tuesday morning and the lack of ice crystals should bring a period of light freezing rain or drizzle. Total snow by Tuesday evening is forecast to be 2-5 inches areawide, with up to 0.25 inches of ice across the higher elevations in the Poconos Region and only a glaze to a tenth of an inch elsewhere. && .SHORT TERM /TUESDAY NIGHT THROUGH THURSDAY NIGHT/... Light snow showers in the area Tuesday night in the wake of the storm with the northwest flow. Main event in the period begins on Wednesday as an arctic cold front plunges into the area. Considerable, deep instability, for winter, accompanies the front with a sharp surface convergence and adiabatic lapse rate will lead to snow squalls along the front. Current timing pushes the front through around midday with strong cold advection firing additional lake enhanced squalls behind the front. With a quick inch of snow and very low visibility and strong wind gusts, snow squall warnings on Wednesday a definite possibility. Lake effect continues into Thursday with a NW flow event and near Advisory snow amounts likely over the northern zones into the Finger Lakes. Despite the extreme instability, limiting factors are evident including extremely dry air and a good amount of shear that may limit the intensity of the band(s). Also, subsidence inversion drops down to near 900mb by Thursday morning. With the cold, temperatures will drop into the single numbers across the area, with some lows below zero in Oneida county. Adding in the winds, wind chills will be approaching Advisory criteria Thursday morning. && .LONG TERM /FRIDAY THROUGH MONDAY/... Westerly flow across the Great Lakes will cause light lake effect snow showers over northern and western sections of the forecast area Thursday before high pressure builds in Thursday night. Temperatures will drop into the single digits Thursday night with below zero readings to the far north. Chilly but quiet weather is forecast for Friday as temperatures rise into the 20s. A weak wave could produce isolated snow showers on Saturday and Sunday. Temperatures will rebound into the middle 30s on Saturday and the upper 30s on Sunday. && .AVIATION /00Z TUESDAY THROUGH SATURDAY/... Conditions remain VFR at all terminals this evening. This will be short-lived, as lower ceilings and precipitation begin to move in from south to north, with KAVP the first terminal to likely see restrictions (likely after 02Z). Expecting all terminals to quickly lower to IFR later tonight as precipitation overspreads the area. While the majority of the precipitation across the area will be in the form of snow, snow is expected to transition to a wintry mix, especially at KAVP, but also briefly for KELM and possibly KBGM. Conditions gradually improve somewhat by the end of the TAF period as the storm system departs. Winds will be light and variable this evening, before becoming easterly, and eventually northerly by Tuesday afternoon at less than 10 knots. Winds shift to a more northwesterly direction as the storm departs late in the period. Outlook... Tuesday night...occasional MVFR in snow showers. Wednesday and Wednesday night...MVFR/IFR restrictions with snow showers and squalls in CNY. MVFR AVP. Thursday...VFR. Possible restrictions in CNY due to lingering lake effect snow showers. Thursday night through Saturday...VFR. && .BGM WATCHES/WARNINGS/ADVISORIES... PA...Winter Weather Advisory until 4 PM EST Tuesday for PAZ043-044- 047-048-072. Winter Weather Advisory until 4 PM EST Tuesday for PAZ038>040. NY...Winter Weather Advisory until 4 PM EST Tuesday for NYZ022-024- 055>057-062. Winter Weather Advisory from midnight tonight to 6 PM EST Tuesday for NYZ015>018-023-025-036-037-044>046. && $$ SYNOPSIS...MPK NEAR TERM...MPK/MWG SHORT TERM...DGM LONG TERM...DGM/DJP AVIATION...BJG/DGM