After last week’s sojourn into the “Ithaca Icebox”, we’ll get somewhat of a reprieve this week, though it won’t by any means be enjoyable. Temperatures should be above freezing during the daylight hours, but with frequent bouts of rain and some snow in the forecast, you’ll want to stay indoors much of the time anyway.
There’s no doubts about it – Thanksgiving Day was freakishly cold. In fact, the night of Thanksgiving was the coldest temperature ever recorded in Ithaca in the month of November. As first reported by Finger Lakes Weather, the -5 °F reported at the Ithaca Game Farm Road weather station at varying times between 3am and 7am Black Friday morning (the 23rd) marked the coldest November observation in 125 years of local record-keeping. According to the Northeast Regional Climate Center, only one other subzero November temperature has been observed in Ithaca in the month of November: a -4 °F reading on November 30th, 1976. In fact, Friday morning’s reading is the earliest subzero recording ever recorded in Ithaca for a winter season.
As much as we’d like to put that all too cold temperature far behind us, there is some evidence that unseasonably early cold and snow portends an unusually cold and snow winter ahead. This is due to a combination of factors. For one, the large-scale conditions that led to the early cold and snow don’t tend to change all that fast. For instance, El Niño develops and wanes over a period of nine months to two years, so it’s impacts tend to be fairly consistent over a shorter period of several weeks to a few months. Secondly, when there’s a lot of fresh snow on the ground, it limits heat radiation back into the atmosphere thanks to its higher reflectivity (albedo) and the fact that, hey, snow is cold. That cools the air above it and imparts a cooling effect on the atmosphere. This cooling can reinforce troughs in the jet stream, which allow cold air to seep down from the Arctic. The long story short – cold temperatures helps support more cold temperatures; warm temperatures helps support more warm temperatures.
Anyway, with that chilly thought, this next week isn’t looking nearly so cold, with temperatures near to slightly below average. However, the week ahead will also be very unsettled, with periods of rain and some snow showers in the mix.
Your Weekly Weather
We’ll start off with a fairly common refrain since mid-October – a storm system entering into the region. In this case, it’s an area of low pressure sliding in from the Ohio River Valley, shifting northeastward into Southern Ontario by Monday night. This is the same storm that brought blizzard conditions to the Chicago and Kansas City areas on Sunday. However, this time, we stay on the warm side of the low – its counterclockwise rotation is pumping milder air to the east of the system. So instead of a blizzard, we get rain. In the meanwhile, a secondary low will develop off the Delmarva Coast and move into Southern New England, which will only add to the unstable conditions aloft, but most likely be too far west to drag down cold air and create snow.
For your Monday, leave the parka at home, but grab an umbrella. Rain will quickly overtake the region by mid-morning, a little closer to sunrise in locations southwest of Ithaca. It will be a rainy, cloudy day, with highs in the mid 40s and a quarter to half an inch of rain, which should start to taper off after sunset. Temperatures will slide back into the mid 30s overnight as the storm circulation passes to the north and cold air begins to come in around the back of the low pressure area, and while you may see a few flakes mixed in with the rain showers, little if any accumulating snow is expected.
Tuesday will be a little cooler as the two low pressure centers merge over northern New England, their combine, larger circulation now tapping into and drawing down colder air from Canada. It will be cloudy with scattered rain and snow showers, and highs in the mid 30s (outlying towns) to upper 30s (urban Ithaca). As the system lingers, we’ll switch over to snow showers Tuesday night, but excluding the usual lake effect areas to the north, any snowfall will be light in intensity and quantity, with a low in the upper 20s and no more than a dusting.
Wednesday will be cold and cloudy as the system slowly moves eastward, with scattered snow showers and a high in the mid 30s. Accumulations of new snow will be an inch or less, much of it dependent on the wind angle and corresponding lake effect snow bands stirred up by the fetch over the lake. Wednesday night will also be cloudy with a decreasing number of showers, and with those clouds, we’ll only fall back to the low 30s for lows.
Thursday will introduce blue skies back into the region, as a high pressure area heads up the Atlantic coast. However, it will remain on the chilly side, with temperatures only making into the mid and upper 30s. Thursday night will be mostly cloudy with lows in the upper 20s. As the high pressure passes nearby, Friday will be more of the same, partly to mostly cloudy skies, dry conditions, and highs in the upper 30s and lows in the upper 20s Friday night.
Another low pressure system is looking to make its way into the region this weekend, and with it, the renewed threat of rain and snow showers. Temperatures will be in the upper 30s to near 40 °F Saturday with mostly cloudy skies and scattered showers, with snow showers Saturday night as lows fall into the low 30s. With stronger southwest flow Sunday, temperatures are looking to be above average for a change, with highs in the upper 40s.
For the first half of December, things are looking to be near or slightly above normal temperature-wise, as a trough in the jet stream settles on the Western United States early in the period, and shifting eastward into the Great Plains in the middle of the month. While this comes with milder temperatures, it also potential comes with storm systems coming in from the southwest, so chances for rain (or snow, depending on timing) will be above normal. Beyond that, early forecasts are showing a cold trend returning for Christmas, but we’ll need to get closer to Santa’s big day before making any firm forecasts.