ITHACA, N.Y. — A glorified rodent in Pennsylvania may be predicting an early spring, and if you looked at this week in isolation, you might be tempted to believe him. Given that we’re at the climatologically coldest time of the year, we should be expecting temperatures in the low 30s, barely breaking freezing for highs and down into the mid teens for lows. However, much like January was, the week ahead is looking to be on the mild side, if wet and potentially stormy Wednesday night into Thursday morning.
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It’s a wintry scene outside at the moment as a warm front begins to push into the Northeast. With cold but not very moist air ahead of the front, some light snowfall is to be expected this afternoon and evening. In the warmer spots, what falls will melt thanks to temperatures being in the upper 30s, but in the higher elevations and more remote areas where the temperature is closer to 32 °F, a light coating is likely to stick to surfaces. The primary axis of instability will be from NW-SE, and currently is centered SW of Ithaca, but will migrate westward through the evening. Groton and Dryden may have some shovelable/plowable amounts, whereas everywhere else shouldn’t have more than an inch or two, an inch or less during the day today and another inch overnight.
The front should advance far enough westward that the snow showers will come to an end in the 2-4 AM timeframe in Ithaca, and a little earlier to the west and a little to the east; generally speaking, everyone should be dry by sunrise. Monday won’t be a bad day for mid-winter, as more stable air takes hold in the Southern Tier. It will be partly cloudy with highs in the mid 40s, so the snow that falls and sticks over the next several hours will largely melt off during the day Monday. Monday night will start off dry, but a few rain showers will work in by daybreak Tuesday as the next storm system begins to work its way in from the Ohio River Valley, a weak short wave pulse of instability along the edge of the jet stream ridge. Lows Monday night will be in the mid 30s.
It’s looking like during the day Tuesday will be all rain, as temperatures once again climb into the mid 40s under otherwise cloudy skies. The rain should be light and sporadic, with a tenth of an inch or less in most areas. As the low moves westward, we’ll shift into the cold side of its counterclockwise flow, and that with the loss of daytime heating will see the last rain showers transition to snow showers Tuesday night as lows drop into the upper 20s.
On Wednesday, a high pressure area building in from the upper Midwest and Northern Great Lakes will reinforce the cooler air with winds out of the northwest. The high will provide stable conditions and partly cloudy skies, but it will be a bit cooler, with highs in the mid 30s in Ithaca and low 30s in the surrounding hill towns. Yet another storm will begin to approach Tompkins County late Wednesday night as another low pressure storm system rides up and around the jet stream ridge now off the Atlantic Coast. It will be cloudy early with snow building in after midnight, and lows in the mid 20s.
This storm that comes through Wednesday night into Thursday could be a substantial event – Quantified Precipitation Forecasts (QPF) from the NOAA Weather Prediction Center estimate about an inch equivalent of precipitation, but the key is what proportion of that is snow (which is ballparked at 10″ of snow per 1″ of liquid equivalent) and what proportion of that is rain, since Thursday morning will see a transition from solid to liquid precipitation. It’s a little hard to be precise at the moment with that changeover in mind, but expect at least a couple inches of snow on the ground Thursday morning, changing over to a cold rain by late morning Thursday. Highs will be in the upper 30s with cloudy skies otherwise.
To make clear the uncertainty of that Wednesday night into Thursday morning forecast, this is from NWS Binghamton’s forecast discussion: “Very difficult forecast in the long term as significant model differences continue to cloud the forecast.” Pun not intentional. This is really one of those knife’s edge situations where a few miles and a degree or two either way could make the difference between a major snow event and a prolonged cold rain, and the models don’t agree which will happen. The ECMWF (European model) has a better track record and is leaning towards a warmer if wetter solution, and the GFS (American model) towards a colder, snowier solution. Keep an eye on the forecast for Thursday morning.
At the moment, the attempted model blend is suggesting this will fall as rain into Thursday night, as the temperatures should stay a few degrees above freezing on the edge of the warm sector of the low while it moves northeastward. Some snow could work its way in colder areas north of Ithaca, however. Lows will be in the mid 30s in the urban core and south/southeast of Ithaca, with temperatures closer to freezing to the north and west.
Friday is looking a bit complicated as way as the storm system begins to lift northeastward out of the region, but for now, expect a mix of rain and snow showers with cloudy skies in between, and highs in the upper 30s. Friday night will see a few lingering snow showers with mostly cloudy skies and lows in the upper 20s.
The weekend is looking aunsettled as a weak shortwave passes between two areas of high pressure, one over Canada and one over the Southeastern U.S. Not expecting anything significant, but plan for a few light rain and snow showers and highs in the upper 30s for both Saturday and Sunday, and lows in the upper 20s Saturday night.
Generally speaking, that ridge in the jet stream will hold fairly steady along the east coast for the next couple of weeks, and some long-range models are suggesting that may hold for the month. That would portend warmer if also wetter conditions for Tompkins County for much of February, as milder air makes its way into the region via the ridge, while storm systems ride along the jet stream at its perimeter, delivering round after round of rain, and potentially snow if the timing is right. The one biggest question mark is a cool down mid-month, though it looks to be a short-term event on the order of a few days if it pans out.