Arctic Blast Set-Up
Low pressure is moving through the Mid-Atlantic region this morning and is about to move out over the open waters of the Atlantic. As expected, precipitation overnight primarily stayed south of the Finger Lakes.
This low should strengthen as it gets out over the open water as it lifts northeast towards far eastern Canada.
Meanwhile, an impressively strong area of high pressure over Central Canada will expand southeast into the United States. An extremely cold air mass to the east of this high will be pushed southward on north winds between these two weather systems.
Unfortunately for the Finger Lakes, the core of this cold air mass is situated just south of the Hudson Bay and has a direct path into our region.
Accompanying this blast of arctic air will be gusty winds and lake effect snow Friday, Saturday, and lingering into Sunday.
Lake Effect Snow
Lake effect snow is already developing off the Upper Great Lakes in Michigan and southern Ontario as that cold air begins to work in. Some disorganized snow showers may develop this morning and into the afternoon across the Finger Lakes. For the most part, though, these will be fairly insignificant.
The lake effect should begin to get better organized tonight. Locally heavy squalls will start across the northern and eastern Finger Lakes before multiple bands set up across most of the region.
These snow bands will be transient, so most areas should see at least a coating of snow overnight, but no one place should see a huge dumping of snow. Highest accumulations will be over the northern and eastern Finger Lakes, where the snow will start soonest.
The snow may consolidate some on Saturday morning and afternoon with a spray of snow showers over the northern and eastern Finger Lakes with some embedded squalls. By the evening, a wider range may see snow once again as the wind direction continues to wobble.
Snow should begin to taper off on Sunday, but some areas could hold onto at least light snow showers well into Sunday afternoon. This would be most likely across the eastern Finger Lakes.
Snow totals this weekend will vary greatly by location. Producing a snow accumulation map for this type of event, where the bands are constantly on the move, is practically futile and would give a false impression of the nature of the event.
Instead, prepare for on and off bursts of snow throughout Friday night, Saturday and early Sunday. Accumulations will range from a coating to a few inches. What does fall will be blown all around, though, leaving some areas bare while others see deeper snowdrifts.
Cold and Windy
Winds will increase during the day Friday as the coastal storm strengthens and high pressure builds in. Wind is driven by differences in air pressure, so as the two systems draw closer to each other, the wind will increase.
For today, wind gusts will be on the order of 30-45 mph. The highest gusts will be over the higher elevations of the Southern Tier and eastern Finger Lakes. With daytime highs near 30 degrees, the wind chill will make it feel more like the teens and single digits.
The wind chill will drop below zero tonight and early Saturday morning. Temperatures will fall back into the low teens while wind gusts will generally be under 35 mph overnight.
Stronger winds and colder temperatures are expected on Saturday, making it a bone-chilling day. High temperatures will top out near 20 degrees. The wind will increase in the morning and remain strong through the day. Top gusts of 40-50 mph will be commonplace, with the highest gusts near Lake Ontario in Wayne and Cayuga counties and over the higher elevations between Syracuse and Ithaca.
The combination of those strong winds and cold temperatures will keep the wind chill between -5 and +5 throughout the day.
Saturday night will see temperatures in the single digits and teens with wind gusts of 25 to 35 mph. More subzero wind chills are likely. Sunday’s winds will remain in the 25-35 mph range, which will result in wind chills mostly above zero with high temperatures again near 20 degrees.
Early Hype for Tuesday/Wednesday
The hype machine is cranking up with mainstream media weather sources jumping all over a potential storm next Tuesday and Wednesday.
While the potential certainly exists for a significant weather event, there are numerous plausible scenarios where the set up does not quite come together. Making a storm requires everything to come together perfectly, and more often than not, it does not, especially in a case like this.
A weak system will move from the Midwest into the Ohio Valley towards the middle of next week. A second, stronger system will move through the Deep South and turn up the coast.
The key will be the speed of the two systems and how quickly they can merge. A quicker merger will result in a storm track inland and could bring significant snow to parts of the northeast, possibly including the Finger Lakes. A later merger, or no merger at all, would keep the storm right along the coast or out to sea altogether.
Storm mergers are extremely complex and computer models often struggle with the process, even just 12-24 hours in advance. There is no accurate way to predict actual storm impacts this far out.
The European model ensembles show this quite clearly, with a huge range of possibilities for next week in the Finger Lakes. It will be a few days yet before there is any chance of making an accurate forecast so don’t buy into the hype just yet.