textproduct: Binghamton

SYNOPSIS

A cold Canadian air mass will continue to pour into the Northeast through the weekend and into early next week with persistent on and off snow showers. The pattern shifts by mid week with temperatures rising and chances for rain and snow later in the week.

NEAR TERM /THROUGH FRIDAY/

Main concerns in the near term are focused on the accumulating lake effect snow off of Lake Ontario and subsequent Lake Effect Snow Warnings in effect for Onondaga, Madison and southern Oneida Counties to Friday morning...with a second focus on northern Oneida County during the day Friday as the LES band lifts north and drops an additional 2 to 6 inches of snow. Therefore, a Winter Weather Advisory has been issued for northern Oneida.

An exiting low pressure system in northern New England is drawing a cold Canadian air mass south across the eastern Great Lakes and the interior Northeast. Cold 850mb temperatures around -15 to -17 deg C moving across 0 to +5 deg C water temperature is creating favorable conditions for lake effect snow. An embedded upper short wave is sweeping around the bottom of the trough and pushing across the area this afternoon. The combination of this trough and the daytime heating is causing enough shear and instability to keep the lake band disorganized and more multi-cellular in nature. Current thinking is that when the sun starts to set and behind the trough, conditions will become favorable for a more organized singular band. This window may be relatively narrow before a loss of moisture, as indicated by numerous guidance sources.

So, the Syracuse metro area and the I-90 corridor over to Utica can anticipate the threat for 1 to 2" per hour snowfall rates from around 3 PM to 8 PM this evening...before the snow intensity pulls back a bit later and into the overnight hours. There will likely still be some accumulations later tonight, but rates are expected to be lower. Total additional snowfall amounts in the Warning area should be around 5 to 8 inches...on top of the couple inches many areas already received today. We are also concerned for the threat of blowing snow. The combination of gusts 20 to 30 mph and light fluffy snow will make for reduced visibilities and potentially hazardous travel conditions.

By Friday morning, the wind flow will become more westerly and allow the lake effect snow showers to shift to the north off of Lake Ontario. There will be a period during the day Friday and into Friday evening where accumulating snow is likely into parts of northern Oneida County. The area is expected to be confined to the northwestern sections of the county around Camden, Florence, and Point Rock. As much as 3 to 6 inches of additional snow is forecast.

Other areas of central NY and northeast PA will remain relatively dry and quiet with cold temperatures persisting...overnight lows tonight into the teens above zero and highs on Friday into the mid to upper 20s. However, the combination of 5 to 15 mph winds will make it feel like the single digits and teens.

SHORT TERM /FRIDAY NIGHT THROUGH SUNDAY/

The next deep low pressure system is expected to drop into the western Great Lakes Friday night and Saturday, which will act to shift the wind flow over Lake Ontario to the southwest, pushing any remaining lake showers farther to the north.

This will allow for a brief break in the snow, but the re- enforcing cold air should keep temperatures in the single digits and teens overnight and only into the 20s and lower 30s during the day for the weekend. The initial short wave rotating around the bottom of the trough will eject to the east Saturday afternoon and trigger a batch of snow showers. Most areas will see generally less than an inch of accumulation...with the warmer valley or low elevation areas only a trace at best. Afternoon highs are only expected to top out in the low to mid 30s on Saturday.

The primary upper low moves to the east on Sunday, which will help draw to the south another shot of colder air. This pattern will be conducive for more lake effect snow showers with highs only in the mid teens to lower 20s.

LONG TERM /SUNDAY NIGHT THROUGH WEDNESDAY/

The lake effect snow off of Lake Ontario continues into Sunday night and Monday morning with temperatures 0 to +15 deg F. The air mass remains cold through Monday night with yet another clipper dropping south and rotating through the region with a quick hit of light snow into Tuesday morning.

The pattern starts to take a warm turn by late Tuesday and especially Wednesday with a broad upper ridge building in across the eastern third of the U.S. and surface temperatures into the mid 30s to lower 40s. The relatively warm southwest flow will contain a series of weak embedded waves which could trigger scattered rain showers. There is still a lot of uncertainty with this pattern, so will need to monitor the trends through the next several days.

AVIATION /18Z THURSDAY THROUGH TUESDAY/

The current gusty and narrow lake effect snow showers across CNY, giving restrictions to most of CNY terminals, will slowly taper off, and a more organized lake effect band will impact mainly SYR, and RME at times. Conditions will improve at all other terminals, eventually to VFR later in the afternoon and evening, besides RME and SYR. Lake effect will continue to impact RME and SYR through the evening.

Outlook...

Friday through Monday...Occasional restrictions possible in scattered snow showers.

BGM WATCHES/WARNINGS/ADVISORIES

PA...None. NY...Winter Weather Advisory from 4 AM Friday to 1 AM EST Saturday for NYZ009. Lake Effect Snow Warning until 7 AM EST Friday for NYZ018-036- 037.