ITHACA, N.Y. — As anyone who’s spent a number of winter in Upstate New York knows, January can be something of a meteorological grab bag. Sometimes it’s frigid, sometimes warm, sometimes stormy, and sometimes quiet.
This week, we seemed to have lucked out in the draw of the card. Apart from some light lake effect Monday, it’s looking fairly quiet for the week ahead, with seasonable to above average temperatures.
Your Weekly Weather
It’s a fairly quiet and chilly Sunday evening as this weekend’s storm system continues to move northwestward into Atlantic Canada. High pressure will slowly build in from the upper Midwest, but the overall flow aloft will be northerly, since we’ll be between the slow-moving low’s counterclockwise circulation, and the high pressure’s clockwise circulation. With the warm winter we’ve had so far, Lake Ontario is still largely ice-free, which allows for the heat energy from the warmer waters of the lake to transmit directly into the colder air passing above, destabilizing the atmosphere. This means lake effect snow showers will be in abundance for Monday.
For tonight though, the primary source of precipitation, which will be light, is a shortwave (pulse of instability) rotating around the backside of the low like the spoke of a wheel. This should push through around midnight and linger through to about sunrise, with maybe a new coating of snow by the time of the Morning morning commute, and a little more than that in the towns north and east of Ithaca. Otherwise it will be mostly cloudy with a low in the low 30s (on the hills) to mid 30s (in Ithaca and close to Cayuga Lake).
Monday will be mostly cloudy with occasional light lake-enhanced snow showers passing through Tompkins County. These aren’t strong or especially widespread, but they will be persistent. Not really expected any accumulation with temperatures in the upper 30s during the day, but as it cools after sunset, a coating of snow may stick to surfaces Monday night as the last of the showers taper off after midnight. Lows Monday night will be in the upper 20s, with mostly cloudy skies once the snow bands dissipate.
Tuesday will be quiet as the last snow showers end in the early morning with near-overcast skies during the day – while the snow will end, Lake Ontario will still provide enough instability for cloud formation downstream. With the brisk north-northwest flow from the high to the west, highs will be seasonably cold, in the mid 30s. The winds will slacken as the high approaches from the northwest, and that will allow the downstream clouds to lose much of their source of energy and break apart. Lows Tuesday night will be in the low 20s with partly cloudy skies.
Wednesday will be a cold, dry day as the high pressure system’s core passes to the north. Plan for partly cloudy skies with a high around 30°F. Wednesday night will be partly cloudy with a low in the low teens.
Thursday will be another seasonably cold, dry day, perhaps slightly warmer as a light southereasterly wind begins to build in as the high moves eastward. It will be partly cloudy with highs in the low 30s. Thursday night will be partly cloudy with lows in the mid to upper teens.
Friday will see a stronger southerly flow on the backside of the high, and temperatures will warm accordingly. Conditions will be dry, with partly cloudy skies and highs in the upper 30s. Friday night will be cloudier as a low pressure storm system begins to build in from the south, and so it will be mostly cloudy with lows in the mid 20s.
At present, it’s looking like the storm system will move off the coast of the Carolinas and track northeastward towards the Maine coast. With the high to its north, although we’d be on the cold side of the low, the high will maintain its broad circulation and funnel in milder air from the east, pumped up by the low. This will be moist, unstable air as well. It’s looking like Saturday will be an unsettled day, with mostly cloudy skies, scattered rain showers and a high in the low 40s. Saturday night will see a mix of rain and snow showers with lows in the low 30s, and Sunday will see more rain showers and a high in the low 40s.
Looking ahead into February, the large-scale environment suggests that a strong polar vortex up at the poles will keep the coldest Arctic air firmly bottled up at the polar latitudes, which isn’t much fun for Alaska, but it is what it is, and allows for milder air to dominate across the lower 48. Later in the period, there does to appear some weakening that could allow for cold air outbreaks by mid month, but at this point it’s too soon to precisely say just how cold and where – initial longer-range models suggest the upper Midwest and Pacific Northwest will be more vulnerable earlier in February, and the Northeast and Midwest may be more vulnerable later on. We’ll see how the situation gets resolved as we finish out the first month of 2020.