ITHACA, N.Y. — Late November tends to be something of a meteorological roll of the dice. Sometimes we have powerful snowstorms roar through, snarling travel for days; sometime we have jacket weather, and a few years ago temperatures went subzero for Thanksgiving.
This year, it’s arguably better than average. Those traveling Monday night and Tuesday will deal with some rain or light wet snow, but after that, your travel plans should have smooth sailing – at least, from Mother Nature’s angle. We can’t forecast other drivers or deranged airplane passengers.
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Skies have clouded over ahead of the next storm system that will impact Ithaca and Tompkins County, that being an area of low pressure passing to the north, through the Canadian Shield and towards Hudson Bay. This system will pinwheel (retrograde west slightly) east of Hudson’s Bay as its eastward passage is halted by running into a large area of high pressure to the east, and the low will slowly divert northward towards polar latitudes, up and around the Atlantic high. In short, it will be close to Ithaca’s longitude and impacting the local weather for a couple of days at the start of this week.
With highs today in the low 50s, several degrees above normal, today was the warm sector of the low, where Tompkins County was in the path of southerly winds in the southeast quadrant of its counterclockwise circulation. The cold front is moving into the region, but there’s enough mild air present that this will be a rain event for tonight and tomorrow. Most of the rain will occur 5-9 PM, with some intermittent showers before and after; this will be light, with rainfall generally less than one-tenth of an inch. Temperatures will slide back into the low 40s after sunset, and upper 30s by sunrise Monday.
The cold front ushers through in the early AM hours Monday, and with winds turning to the northwest, Monday will be a cold and blustery day, with decreasing clouds locally and highs stuck around 40°F. Those cold northwest winds will be well-suited for tapping into the heat energy of Lake Ontario’s warmer water, and the lake effect snow machine will crank up accordingly.
The angle of wind fetch makes this more of a Syracuse/Auburn event, so the snowbands will set up north and east of Ithaca, but if you’ll traveling through those areas Monday night into Tuesday, give yourself some extra travel time, as there will likely be moderate, fluffy snow in a narrow band that limits visibility and makes the roads slick. The bands may clip areas northeast of Ithaca, but generally snowfall amounts in and around Tompkins County will be no more than a coating to an inch by late Tuesday morning, with cloudy skies otherwise and Monday night lows in the upper 20s.
Tuesday will start off with a few remaining snow showers that may turn to rain showers around midday. These peter out as a high pressure system makes its way in with more stable air, too much for the lake’s surface heat to destabilize. Expect mostly cloudy skies to turn sunnier by late Tuesday afternoon, but highs remaining in the upper 30s. Tuesday night will be dry, cold and quiet, with partly cloudy skies and lows in the mid 20s.
Wednesday will see a light southerly wind from the high pressure centered over the Central Appalachians, and this will result in a decent day for late November. It will be mostly sunny with highs in the mid to upper 40s. Wednesday night will remain dry and quiet, with a few passing clouds and lows in the low 30s.
For your Thanksgiving Day feasts, the weather is actually looking pretty good for those of you who might have a Turkey Trot or post-dinner walk planned. The winds take a more southwesterly angle, and the leading edge of the next storm system will amplify the winds, resulting in a southwesterly breeze ahead of the system. It will be mostly cloudy during the day, with highs in the mid 50s. Some rain is likely to move in after sunset, though this next system will have limited moisture, and so the rain will be light and sporadic overnight. Plans for light rain showers, mostly cloudy skies Thursday night, and lows in the upper 30s as that cold front moves through around midnight.
Friday will be cooler, with the lake effect firing up again to the north, but generally quiet in Ithaca/Tompkins, with a few rain showers early, followed by mostly cloudy skies. Highs will be in the low 40s. Friday night will see mostly cloudy skies with a stray rain or snow shower to the north of Ithaca, with lows in the upper 20s.
Looking into next weekend, it will be on the chilly side, but dry. Expect partly cloudy to mostly cloudy skies Saturday and Sunday with highs in the mid to upper 30s, and lows in the mid 20s.
The medium-range outlook calls for a cool start to December, as the prevailing jet stream pattern favors a high pressure ridge in the Western and Central United States, and a downstream trough. However, the orientation will favor drier continental air over much of the continental United States (the moist Pacific Ocean air over the Pacific Northwest being the major exception), so precipitation will be near normal for the period, but more likely to be in the form of snow. The setup has the jet stream trough a little too far eastward for major coastal storms, but we’ll need to see what the day-to-day setup is like as we enter into December.