ITHACA, N.Y. — After a brief warm spell last week, we’re taking another plunge on the thermal roller coaster with subzero temperatures possible Monday night, followed by another ascent with temperatures likely in the 50s for Thursday, with cooler temperatures over the weekend. Buckle up, folks.

Your Weekly Weather

It’s a cold and cloudy day across Tompkins County as an Arctic high passes over Ontario and a developing coastal storm system moves from the mid-Atlantic towards Cape Cod. Like two gears turning, that developing low is pulling further southward Arctic air wrapped around the high to its northwest. This air is passing over Lake Ontario and creating some substantial cloud cover as well as some scattered lake-enhanced snow showers across the Finger Lakes.

The coastal storm system will remain far enough to the east that no precipitation is expected directly from the storm, though the cold air advection will continue as the storm strengthens and its deepening pressure gradient allows it to build up wind gusts and bring in greater amounts of polar air from the north. The scattered snow showers will continue into the overnight hours with mostly cloudy to overcast skies, but accumulations will generally be one-half of an inch or less. Daytime highs in the low 20s this Sunday will fall back into the 0 to +5°F range across most of Tompkins County by Monday morning, with windchills in the -10°F to 0 range, so do bundle up and take some time to warm up the car as you come back from your Super Bowl gatherings late this evening.

Hopefully your Valentine’s Days will be warmer than the weather Monday. As high pressure builds in from the west, skies will clear and it will be quiet day, but a stiff northwesterly breeze will have already cold temperatures feeling even colder. Highs will be in the upper teens, but the windchill will hover within a few degree of zero for most of the day. Your candlelight dinners may benefit from a few more candles for warmth as Monday night sees partly cloudy skies and calming winds, but temperatures hovering in the 0 to +5°F range for lows, with plenty of subzeros likely as calmer air allows air to radiate away heat more efficiently.

Tuesday will be somewhat warmer as the high takes shifts east and calm winds allows temperatures to warm – just as still air allows for heat to radiate away more efficiently, it also allows air to absorb heat radiation more easily. Expect quiet conditions Tuesday with mostly sunny skies and highs around 30°F. Tuesday night will be mostly clear and cold with lows in the mid teens.

Wednesday will see another jump in temperatures as the strong high, now centered over Maine and Atlantic Canada, is pressed upon by a low-pressure system over the Upper Midwest. This will create a strong pressure gradient and strong southerly flow on the backside of the high, which will warm up Upstate New York considerably. The weather will also be quiet, as the storm will for the time being be too far away to produce inclement weather locally. Expect mostly sunny skies and highs in the mid 40s. Wednesday night will see clouds build as the low moves eastward and closer to Tompkins County, but it will remain dry and mild, with mostly cloudy skies Wednesday night and lows in the low 40s.

Thursday will be a washout. It will be warm as the rain moves in, to be sure, with strong southerly flow continuing through sunset. Highs will be in the mid 50s. But it will also rain pretty much the entire day, with gusty southerly winds up to 35 MPH. After sunset, the cold front moves through, but as winds turn to the northwest, they may gust over 40 MPH late Thursday evening, which combined with soggy soils could result in trees coming down, and a high wind advisory may be needed. The winds will weaken a little bit during the overnight hours, but it will remain breezy into Friday morning. The rain will taper off by about midnight with some lingering rain showers turning to snow showers and largely tapering off by daybreak Friday, as temperatures drop from the low 50s at sunset and into the low 20s by sunrise.

Friday will be drier but colder as high pressure builds in from the southwest, Expect partly cloudy skies with highs in the upper 20s. Friday night will be cold and quiet, with a few passing clouds and lows in the lower teens.

A weak storm system does appear in the latest model runs for next weekend, likely to pass north of Tompkins County as it swings eastward through the Great Lakes – this far out, it’s always worth keeping an eye on as we go through the week. At this point, Saturday looks like a mix of rain and snow showers with highs in the mid to upper 30s, while Saturday night sees clearing conditions and lows in the lower teens. Sunday looks to be drier with partly cloudy skies and highs in the mid 30s.

Extended Outlook

A broad change to the flow of the mid-latitude jet stream is expected as we head into the last week of February, with the “western ridge/eastern trough” pattern that’s prevailed over most of the past several weeks flipping to a western trough and eastern ridge setup. This would allow for moisture to funnel northward from the Gulf as storm system ridge up along the ridge over the Great Plains and Upper Mississippi River Valley, but here in the Northeast, embedded under the ridge, precipitation is expected to be near normal with warmer than normal conditions to close out the month.

Brian Crandall

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