textproduct: Binghamton

SYNOPSIS

Cold Canadian air moves in behind the front with lake effect snow showers today through Monday. A weak wave of low pressure drops out of Canada on Monday afternoon with with more widespread snow showers. Warmer conditions develop by midweek with chances for rain increasing on Thursday with an approaching cold front.

NEAR TERM /THROUGH MONDAY/

650 AM Update

Winter weather advisory will expire at 7 AM EST across NE PA this morning. The light snow is now exiting the area with little to no additional accumulation expected.

Previous Discussion Below

Light to moderate snow will continue across the southern Catskills and NE PA through about daybreak before exiting east out of the forecast area. Best estimates are that 2-4 inches of snow has fallen across a good portion of the Wyoming Valley and Poconos as of 3 AM EST, with another inch or so expected to fall by the time the snow ends around 7 AM EST. A Winter Weather Advisory remains in effect for this area of NE PA until 7 AM. Local PA511 traffic webcams show many interstates well covered in snow early this morning, with observed visibility down below 1/2 mile at times being reported by the ASOS at AVP and PA mesonet stations. Temperatures will hold in the mid-10s to mid-20s early this morning.

Winter weather advisories for lake effect snow are in effect for northern Oneida county, and go into effect later this morning/midday for Onondaga and Southern Cayuga Counties.

The next main story will be the return of lake effect snow and snow showers today. A lake effect snow band is currently extending off the east end of lake Ontario across Oswego county and into NW portions of Oneida county; near Camden and Florence. Model guidance shows this lake effect snow band gradually dropping south, to along the Onondaga/Oswego county border by around 8-10 AM EST this morning. Before that time, several inches of snow are likely to accumulate across NW Oneida county.

By late morning, the lake effect snow band will very gradually nudge south into northern portions of Onondaga county, and central Cayuga. A cold frontal passage then picks up the lake effect snow band and drops it south, while transforming into multi-bands this afternoon. Lake effect snow showers rapidly blossom across the Finger Lakes region later this afternoon and evening in the very cold NW flow pattern, as 850mb temperatures fall to around -18C and moisture increases on the back side of the 500/700mb low. The closed mid and upper level low does open up into a positively tilted trough by evening. A well aligned NNW flow continues this evening, with multiple lake effect snow bands likely extending across the Finger Lakes and into the Twin Tiers of NY/PA. Snow to liquid ratios are forecast to be very high late this afternoon and evening, likely around 20:1. Forecast soundings from the 00z NAM show co-located atmospheric lift centered with a well moistened snow growth layer between about 2k ft agl to 6k ft agl...the snow growth layer gradually lowers overnight as temperatures fall...getting down to about 1.5 k ft agl around 1 AM EST early Monday morning. While snow amounts are only expected to be marginal, between about 2-6 inches in the advisories zones, there will also be some gusty NW winds up to 25 mph which could create localized lower visibility and blowing snow at times. Outside of the main lake effect zones, there will still snow snow showers and flurries around this afternoon into tonight. It will be turning very cold, with lows in the single digits to lower 10s. Combined with the wind, apparent temperatures will bottom out between about 0 to 10 below zero in many areas.

The lake effect snow showers attempt to consolidate, and gradually lift back north heading into Monday morning, as upper level ridging starts to build in, backing the flow more westerly in the boundary layer. The next shortwave clipper system looks t move into the area Monday afternoon and evening, bringing a period of light warm air advection snow to most of Central NY and perhaps parts of NE PA. Minor snow accumulations up to about 1 inch are expected from this weak weather system. Monday will feature more cold and below average temperatures as highs only reach into the 20s.

SHORT TERM /MONDAY NIGHT THROUGH WEDNESDAY NIGHT/

A few scattered snow showers and lake effect snow will still be around behind the shortwave disturbance for Monday night. The low level flow looks to be more west or even west-southwesterly, which would push the bulk of the lake effect snow showers north of I-90 overnight. For the rest of the area clouds gradually decrease, becoming mostly clear from south to north overnight. Another cold night, with lows in the single digits to mid-10s expected. The lake effect snow showers are forecast to shift even further north on Tuesday, with a good chance for morning sunshine across the Twin Tiers and NE PA. Clouds do eventually increase heading into the afternoon as a weak wave approaches. Temperatures will still be running below average, with highs in the 20s once again. Tuesday night features dry weather, partly cloudy skies and a steady south wind between 5 to 15 mph. Not quite as cold, with seasonable lows in the mid-10s to low 20s.

Wednesday features mostly cloudy conditions with a chance for afternoon rain and snow showers, especially across CNY as a shortwave rolls by to our north. Otherwise, it will be milder with highs forecast to reach the upper 30s to lower 40s under a steady southwest wind around 10 mph. Brief high pressure brings partly cloudy and seasonable weather for Wednesday night.

LONG TERM /THURSDAY THROUGH SATURDAY/

Thursday is looking very warm out ahead of a strong cold front and low pressure system, with highs reaching the low to mid-40s. With the warm air in place, the initial phase of this system is expected to bring rain showers, and possibly even some gusty showers as LLJ increases to near 70 knots at 850 mb late Thursday afternoon and evening. Behind the cold front, lingering precipitation will transition to snow showers by Friday morning or afternoon as 850mb temperatures fall back to around -12C to -15C. Lake effect snow showers will be possible in the cold northwest flow heading into Friday night.

Model guidance begins to diverge towards the end of the forecast period, however the overall pattern appears to remain active through the upcoming weekend, with chances for snow and rain showers each day and fluctuating temperatures.

AVIATION /13Z SUNDAY THROUGH THURSDAY/

Light snow will taper to flurries and end over the next hour or two across most of the area.

Otherwise as winds turn north northwesterly, lake effect snow showers will become the primary concern, with IFR restrictions possible today, especially near SYR and RME, before activity becomes more scattered and shifts south impacting ITH, BGM and ELM by the late afternoon and evening. There could be occasional IFR vsby restrictions at BGM and ITH in this time frame. Overall MVFR ceilings are expected to linger across most sites throughout this period with some moments of VFR possible.

Northwest winds increase today and into tonight, mainly 6-15 kts, with gusts up around 20 kts expected.

Outlook...

Monday...Occasional restrictions with a period of lake effect snow showers, and more widespread snow showers expected for the afternoon and evening hours.

Tuesday through Wednesday... Mainly VFR.

Thursday...Potential frontal passage with rain showers and minor restrictions possible.

BGM WATCHES/WARNINGS/ADVISORIES

PA...None. NY...Winter Weather Advisory until 5 PM EST this afternoon for NYZ009. Winter Weather Advisory from noon today to 7 AM EST Monday for NYZ017. Winter Weather Advisory until 7 AM EST Monday for NYZ018.