197 FXUS61 KBGM 190236 AFDBGM Area Forecast Discussion National Weather Service Binghamton NY 936 PM EST Wed Dec 18 2019 .SYNOPSIS... Arctic air will plunge into the area overnight bringing lake effect snow and snow showers, along with bitter cold. The cold will last into Thursday with scattered snow showers. Milder air will return for the weekend with dry conditions. && .NEAR TERM /THROUGH THURSDAY/... Increased snow shower coverage a bit with the evening updates based on latest trends and observations through the late evening. This includes some enhancement off of the Finger Lakes that extends from Ithaca to Binghamton. While a few moderate snow showers are present, instability is decreasing which will lead to decreasing coverage outside the lake effect as we head toward morning. The latest mesoscale model guidance is really dropping temperatures several degrees lower than forecasted overnight. However, winds are staying up along with clouds so the late evening update only slightly dropped expected overnight lows. Single digits regionwide. Northwest flow lake effect continues, enhanced by an upper wave swinging through the trough. This will continue the lake effect overnight into the Advisory area. Mesoscale models still show a single band dropping through the northern zones connected to Georgian Bay, weakening as it hit the southern tier of NY. Behind that, upper flow becomes more northerly resulting in a broader, more sheared lake snow area across central NY and even into the Catskills that lingers into Thursday. Snow amounts will range into the high end of the Advisory criteria over Madison and Onondaga, less further to the east and south. Other concern overnight is the cold, with lows in the the single numbers and even below zero in a few spots, and with wind apparent temps -10F to -20F. Wind chill Advisory is well positioned outside of the current advisory for snow. Snow showers slowly wind down Thursday, but will probably linger into Thursday night as light snow showers and flurries. Persistent and cold northwest flow off the keep the activity going. && .SHORT TERM /THURSDAY NIGHT THROUGH FRIDAY NIGHT/... 245 PM UPDATE...Little to change in the short term under building high pressure and dry air. Expect slowly moderating temps and clearing skies. Previous discussion... Friday and Friday night... High pressure remains in control and ridging aloft is forecast to strengthen. We should experience a bright, low angle mainly sunny day as a result. Warming will be hard to come by after the cold start and with the area still within the thermal trof...temperatures will struggle to get to the low and mid 20s during the day. Some warm advection will begin Friday night, but is expected to be offset by land based cooling. Will continue with overnight lows in the single digits and lower teens which would be a a degree or two warmer than Thursday night over the eastern counties. && .LONG TERM /SATURDAY THROUGH WEDNESDAY/... Medium range operational models and ensemble guidance are in fair agreement and suggest that this period will feature generally high pressure blanketing the region with a buildup of anomalous warmth through early next week. 850 mb temperature anomalies reach approximately 6-12 degrees C above seasonal norms by Tuesday, which would support 2m max temperatures ranging from the mid 30s to mid 40s. Precipitation anomalies suggest an unusually quiet period with models indicating a distinct split of northern and southern streams with the southern one being the most active. Weak features passing through the northern branch currently appear moisture starved. As a result, will follow the rather dry NBM PoP guidance pretty closely. The prospects for a white Christmas are looking rather pessimistic as the existing snow cover should succumb to these rising temperatures. && .AVIATION /03Z THURSDAY THROUGH MONDAY/... Generally MVFR through tonight. Brief snow showers may reduce visibilities and ceilings to IFR till about 03Z or so. MVFR visibility reductions from snow showers are likely through most of the night except for KRME and KAVP. Northwest winds will continue to be gusty throughout the night with gusts around or even a bit more than 20 knots from the northwest. Conditions look to be just under LLWS criteria as well given As we head into Thursday, ceilings will slowly lift with KAVP, KRME and KELM lifting in the morning. KBGM, KITH and KSYR should have MVFR ceilings throughout the day. Northwest winds will also be on the slow decrease. Outlook... Thursday night through Sunday...VFR. && .BGM WATCHES/WARNINGS/ADVISORIES... PA...None. NY...Wind Chill Advisory until 10 AM EST Thursday for NYZ009-037- 046-057. Winter Weather Advisory until 7 AM EST Thursday for NYZ017-018- 036-044-045. && $$ SYNOPSIS...DGM NEAR TERM...DGM/MWG SHORT TERM...JAB LONG TERM...JAB AVIATION...MWG