ITHACA, N.Y. — For those looking for a layer of snow to make the holiday season festive, this isn’t your week. While conditions will be unsettled for much of the week ahead, precipitation will largely be in the form of rain as temperatures top out in the 40s or higher over the next several days. Bing Crosby can keep dreaming for now.
Colder and calmer weather today as a Canadian air mass hangs out over the area. Lake effect showers will gradually move north of the region by the early afternoon. #NYWX #PAWX pic.twitter.com/WY1MGBK5g6— NWS Binghamton (@NWSBinghamton) December 4, 2022
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High pressure over the Southeastern United States is attempting to keep a Canadian shortwave (pulse of instability) at bay as the weak area of passes to the north. This shortwave will be absorbed into a stronger Alberta clipper low tonight, but the northeastward movement of the high should keep the storm system from making headway into Upstate New York until late Monday.
The combination of downstream clouds from lake fetch and high clouds aloft has created mostly cloudy skies across the area, though skies should steadily clear out later today as the core of the high pressure system moves closer to the region. It will be a fairly quiet day to close out the weekend, with seasonable highs topping out in the lower 40s, perhaps upper 30s if the clouds prove to be more persistent. With the relative lack of daylight in December, it’s a little hard to build on daytime heating.
Looking into Sunday night, it will be quiet and chilly. Skies will clear out to provide for near-clear skies with lows in the lower 20s, and mid 20s in urban Ithaca and along the shores of Cayuga Lake.
On the backside of the high Monday, winds will come in out of the south, which will boost the temperatures a few degrees, enhanced by counterclockwise flow ahead of the clipper low to the north. Highs will be in the mid to upper 40s Monday, but clouds will increase during the day ahead of the cold front associated with the Canadian low. Monday night will turn overcast with rain showers moving in after midnight as the front approaches. A gusty south wind will assist in keeping temperatures relatively mild, with overnight lows in the upper 30s.
The high pressure system, now over Atlantic Canada, will cause the frontal boundary to stall out west of Ithaca. This will create a rainy Tuesday, if mild for this time of year. Expect periods of light rain, overcast skies, and highs near 50. Tuesday night will be more of the same, with on-and-off light rain showers, cloudy conditions, and lows in the lower 40s.
Wednesday sees the cold front slowly crawl across Tompkins County, passing through Ithaca a little before sunset. This will allow for one more mild day ahead of the front, though still cloudy with scattered light to moderate rain showers. Highs will be in the mid 50s. Wednesday night will see showers tapering off, but the clouds will persist through the overnight into Thursday morning; this will also slow the drop in temperature even as winds turn to the northwest, with lows in the upper 30s.
Thursday sees high pressure briefly build in from Canada; unfortunately, it is likely to be short lived. A developing low pressure storm system over the Southern Great Plains will begin to move northeastward during the day, into the Ohio River Valley and then into the Northeast for Friday. But for Thursday, it will remain dry with mostly cloudy skies and highs in the mid 40s. Thursday night will see a few rain showers, or snow showers closer to sunrise as that southwest low approaches. Lows will be in the low 30s.
This time around, the model consensus is that the low levels off in latitude around Pennsylvania and tracks straight east. That would mean no warm southerly wind as we remain outside the warm sector southeast of the low’s core, and it also creates a rather unusual east wind over Tompkins County. However, the models disagree on how strong the Canadian high is and how far north the precipitation shield of the low gets, so there’s below-normal confidence in the forecast for Thursday night into the weekend. For now, plan for snow scattered rain and snow showers Friday, with mostly cloudy skies and highs in the low 40s. Friday night sees a few snow showers behind the low, with mostly cloudy skies and lows in the upper 20s.
Looking into next weekend, once again taking into account the below-normal confidence in forecast models, it looks like Saturday will be drier with some potential lake effect rain and showers to the north and west, and highs in the low 40s. Clouds increase Saturday night with lows around 30, and another shortwave Sunday will produce scattered rain and snow showers with highs in the low 40s.
Peering into mid-December, the large-scale pattern is broadly showing a trough in the jet stream over the Pacific Northwest, and then rising into a ridge through jet stream from the Desert Southwest northeastward through the Western Great Lakes. This configuration is expected to produce warmer but somewhat wetter than usual conditions in the Northeast, Tompkins County included. In other words, up through the middle of the month, Bing Crosby will still be dreaming of his snowy white landscape, because it doesn’t look likely to happen in the next couple of weeks.