494 FXUS61 KBGM 151141 AFDBGM AREA FORECAST DISCUSSION National Weather Service Binghamton NY 641 AM EST Sat Dec 15 2018 .SYNOPSIS... A complex weather system will impact the region this weekend. The first weaker wave of low pressure is moving through early this morning, bringing a chance for light rain from the New York, Pennsylvania border south. The next, stronger low moves through late tonight through Sunday night, bringing a wintry mix to the area. Monday and Tuesday will be colder with snow showers. && .NEAR TERM /THROUGH SUNDAY/... 640 am update... Just minor changes. 3 am update... Light rain is tapering off to sprinkles early this morning as the better support moves away. Rain will move south this morning leaving a mainly dry mild day today. Rainfall amounts the rest of today under a tenth of an inch for NEPA and Sullivan County NY. Temperatures will be tricky as a surface front drops south. Drier and cooler air will move south at low levels under the inversion. This will keep most of NY around 40 while southern areas are mid and upper 40s. Behind the front clouds will lift and become broken. The front will stall along the NY/PA border. From tonight through Sunday, it becomes messy literally and figuratively. Models all show mixed precipitation mostly in the form of freezing rain. This is expected late tonight and Sunday morning. With the lowest 5k ft near freezing precipitation type could be anything. Low level Dry air over the area will evaporatively cool as moisture saturates the column from aloft tonight. In addition some cold air will be brought in on the northwest side of a closed upper level low. A closed upper level low will move ENE to the mid Atlantic coast Sunday. To the northeast of that low, a surface low will be. This will push rain into the area from the southwest. Models vary on how far north this rain gets which is crucial, since the further north you go the colder low levels are. Also crucial will be the timing. The general theme is to bring rain into Luzerne this evening, the rest of NEPA late tonight, then CNY Sunday. The far south is expected to stay above freezing including the Scranton/WB area. Across the twin tiers into the Catskills has the best potential for up to a tenth of an inch of ice and up to half an inch of sleet. Further north light precipitation should arrive around daybreak. Temperatures here will be the coldest and in the 20s. Sunday mixed precip changes to just rain from west to east during the morning and early afternoon. Freezing rain could linger over the higher terrain of the upper Susquehanna Region and Catskills in the afternoon. Highs recover into the mid and upper 30s late in the day as the steady precipitation moves out of the area. Given the uncertainties on the locations and amount of freezing rain will wait to issue a winter weather advisory for tonight and Sunday. && .SHORT TERM /SUNDAY NIGHT THROUGH MONDAY NIGHT/... 415 AM Update... Transition from lingering wintry mix, to a gusty cold air advection/lake effect snow shower regime will occur during the short term period. For Sunday night, upper low and its pool of deeper moisture will shift to the east, but there will be very little cold air advection due to immediate ridging ahead of another wave that will be descending through western Ontario en route to our region. Thus the saturated layer becomes fairly shallow as deeper moisture leaves, and thermal profiles show difficulty in getting better ice crystal initiation. What this means, is that though precipitation chances will be lowering with time, the precipitation type could still support light wintry mix including perhaps a bit of freezing rain where temperatures dip below 33 degrees. Best chances for any additional light icing will be east of I-81 in the higher terrain. On Monday through Monday night, the more abrupt punch of cold air advection will arrive courtesy of a robust wave punching into the Northeast. However, with so little time between systems, moisture will be very limited and once again rather shallow. The air mass advecting in will originate out of the Canadian high plains; thus plummeting dewpoints. The more noticeable thing will be the push of gusty northwesterly winds. They will pick up to sustained 10-20 mph with gusts 25-35 mph Monday, with only a gradual diminishing through Monday night.l Scattered to likely snow showers are a good bet southeast of Lake Ontario but actual accumulations will be on the light side do to the limited moisture. Model soundings depict the dendritic growth zone at the very top of the cloud layer. All told, we are only figuring on 1-2 inches or so of snow accumulation via northwest flow lake effect. This would include the greater Syracuse-Utica- Norwich-Cooperstown areas and perhaps reaching Cortland- Oneonta-Delhi. Further south, scattered snow showers and flurries and only light skiffs of of accumulation if any. Temperatures will not move much Monday with highs of 30s under cold air advection; Lows Monday night mid teens-lower 20s. && .LONG TERM /TUESDAY THROUGH FRIDAY/... 415 AM Update... Forecast adjusted to account for latest multi-model blend and trends. General themes unchanged from below, including incoming milder temperatures; though confidence has increased for a southern stream system to bring likely rain to the region Thursday night through Friday. As has indeed been the case in the many days leading up to our current situation, things may change and evolve with time. With a good 5-6 days to go before this next amplified moist system, we will continue to monitor the potential for any impacts. Previous discussion... NW flow snow showers continue into early Tuesday, followed by ridging to hold through the end of the period. Building upper heights and a developing southerly flow on Wednesday will allow temperatures to rise above normal for the mid week period. Dry weather will prevail as well, although a complex system developing over the southern U.S. may push some rain showers into the region right near the end of the long term. && .AVIATION /12Z SATURDAY THROUGH WEDNESDAY/... 630 AM update... AVP is at fuel alternate MVFR cigs and MVFR vsbys. Vsbys may fall to IFR this morning until 14z. Low MVFR to continue to 15z then to high end MVFR cigs only with vsbys going VFR. At 17z cigs go to VFR and stay there through 06z. At that time cigs fall back to MVFR with light rain. In CNY, a band of MVFR cigs is dropping southeast with a cold front this morning. RME/SYR now until around 14z, then BGM/ITH 13 to 17z. Both of the latter stations could fall to fuel alternate MVFR. ELM might even drop to MVFR briefly 14 to 16z. BGM/ELM/ITH should fall to MVFR cigs around 09z tonight in light rain. Winds will be north shifting to northeast all at 5 knots. Late tonight possible further turning to east. Outlook... Sunday...Showers and associated restrictions, especially southern tier down into Northeast PA. Could see mixed precipitation as well. Sunday night through Tuesday...Possible restrictions in snow showers, especially NY terminals. Wednesday...Likely VFR. && .BGM WATCHES/WARNINGS/ADVISORIES... PA...None. NY...None. && $$ SYNOPSIS...TAC NEAR TERM...TAC SHORT TERM...MDP LONG TERM...DGM/MDP AVIATION...TAC