ITHACA, N.Y. — A quick-moving low pressure storm system is delivering a volley of fresh snow across much of Upstate today, and temperatures over the next few days will be below normal as cold Canadian air is pulled down on the backside of the low. On the bright side, literally and figuratively, it should be sunny in the days to follow, though another storm system will saunter through from Thursday evening into the weekend.

Your Weekly Weather

A clipper low is crossing Upstate New York this Sunday, dropping a widespread light to moderate snow across the region. Generally speaking, accumulations will be lower in Western New York thanks to slightly warmer air allowing some rain to mix in, while the highest amounts will be at higher elevations between I-81 and I-87. The Catskills and Southern Adirondacks could see some 6-8″ amounts, maybe even a 10″ reading on the high end. If you’ll be heading down I-88 or Route 17 tonight or tomorrow morning, do use caution and give the plow trucks some space.

Locally, snowfall amounts will be somewhat less. The consensus is 1-2″ in and around Cayuga Lake where the air is just a tad warmer and could allow from some brief rain in the mix, and 2-4″ on the hilltops and in the towns surrounding Ithaca. The snow will become more showery later this evening, with showers continuing through the overnight hours and winding down tomorrow morning. With the thick cloud cover, temperatures won’t fall back much tonight, from today’s highs in the mid 30s to lows around 30.

Monday will be a quieter day as winds turn to the northwest on the backside of the low. Those winds will be strengthened as the low pressure deepens over the warm waters of the Atlantic Ocean, and these winds will pull larger amounts of frosty air into the Finger Lakes and Southern Tier. A few morning snow showers will peter out, with cloudy skies beginning to break up late in the day. Highs will be in the low 30s. Monday night will host quiet but cold conditions as a polar Canadian high builds into Tompkins County. Skies will see decreasing clouds, becoming mostly clear after midnight, with lows around 20 in Ithaca and in the teens in the outlying areas.

Tuesday will be chilly but peaceful as the high pressure remains in control. The clipper low will have strengthened and moved northward into Atlantic Canada, which will enhance the northerly flow of cold air further. Skies will be mostly sunny with highs in the mid 30s. Tuesday night will see partly cloudy skies and dry conditions with lows in the low 20s.

Heading into Wednesday, the strong low over Atlantic Canada will nudge temperatures down, though the Hudson Bay high will remain in control overall. Skies will be partly cloudy with highs in the lower 30s. Wednesday night will be partly cloudy with lows in the low 20s, perhaps rising into the mid 20s as the high shifts eastward and light southerly winds kick in after midnight.

Thursday sees the deterioration of conditions as a large but not particularly strong low develops over the Northern Great Plains, drifting slowly towards the northeast. The low will amplify southerly flow, with a stiff breeze and highs in the upper 30s as skies become mostly cloudy to overcast. Light snow is likely to spread across the areas during the afternoon and evening hours, though accumulations may be limited as rain enters the mix at these marginal temperatures. Snow and rain will continue through Thursday night with gusty south winds and lows in the mid 30s.

Looking into Friday, a secondary coastal low is forecast to develop in the larger circulation of the Midwest low – you can thank the warm, energy-laden waters of the Atlantic Gulf Stream for that. A combination of rain and snow is expected with overcast skies and highs around 40. The secondary low will turn winds to the north-northwest Friday night, though these become more westerly by Saturday as it moves northward into coastal New England. Expected scattered rain and snow showers becoming all snow showers, with lows around 30.

As for next weekend, it’s looking like it’ll be unsettled with a combination of rain and snow showers as the New England low spins into Quebec and becomes the dominant low as the Midwest core transfers its energy eastward. But the air flowing over Tompkins County would be more northerly and continental, which is lower moisture, and lower accumulation by extension. This far out, things can change, so take that with a dose of caution. Highs will be in the mid to upper 30s both Saturday and Sunday, with lows in the mid 20s.

Graphics courtesy of the NOAA Climate Prediction Center

Extended Outlook

Looking into the medium-range in the days leading up to Christmas, there’s a good chance many places that don’t normally see a white Christmas will be pleasantly surprised this year. The large-scale pattern calls for a large-wavelength jet stream trough with the highest amplitude over the Northern Plains. Virtually the entire lower 48 will be below normal temperature-wise, though the coasts will be less extreme. On the precipitation side of the equation, it’s looking to be near-normal for the period, so Tompkins County may have some of the white stuff hanging around as the holidays come around later this month.

Brian Crandall

Brian Crandall reports on housing and development for the Ithaca Voice. He can be reached at bcrandall@ithacavoice.com.