A significant winter storm will make for dangerous travel conditions around the Finger Lakes on Friday. This is a complex system and it is very important to read the forecast and understand its intricacies — simply looking at a snow map will not adequately prepare you for this system.
Precipitation will move into the Finger Lakes Thursday afternoon as a few rain showers which will transition to a steady rain Thursday evening as low pressure tracks into northwestern Pennsylvania.
Cold air will work in tonight as the low tracks across Pennsylvania. Rain will change to snow first over the higher elevations of the Southern Tier, then over the northern Finger Lakes towards midnight, over the eastern Finger Lakes after midnight, and lastly across the valleys of the central and eastern Southern Tier a bit before dawn on Friday.
A second low pressure will then develop off the coast of New Jersey, becoming the dominant system. Snow may come to an end for western areas of the Finger Lakes by noon Friday, but heavy snow will continue over the eastern Finger Lakes and Central New York.
The complexities of this system are immense, from timing the change over from rain to snow to determining where the heavy snow band will set up after noon on Friday. The result will be highly variable snow amounts throughout the region.
Additionally, winds will be strong from the northwest on Friday. Blowing and drifting snow will become problematic with near blizzard conditions possible at times. Poor travel conditions are likely even after the snow tapers off.
Phase 1- Thursday Evening & Friday Morning
The first part of this storm will begin Thursday evening and continue into Friday morning as the first low tracks across Pennsylvania.
Rain will move into the region from southwest to northeast, starting as some scattered showers and transitioning to a steadier rain.
Snow will begin to take over as the main precipitation type first over higher elevations in the western Southern Tier as early as 8 or 9 pm. Snow will gradually spread north towards Rochester, then east along I-90 around midnight.
After midnight, the change over to snow should begin across the central and eastern Finger Lakes. The last areas to turn over will be the valleys of the Southern Tier a couple hours before sunrise.
By dawn Friday morning, significant snow accumulations over the western Finger Lakes will have taken place. Several inches will have fallen further east, but with more to come.
The snow should taper off over the western Finger Lakes during the morning, possibly even coming to an end for some areas. Further east, heavy snow will persist throughout the morning.
During this phase, winds will also become strong, with gusts over 40 mph possible. This will create significant blowing and drifting, resulting in near blizzard conditions at times.[wp_ad_camp_1]
Phase 2- Friday Afternoon & Evening
As the second low takes over, a frontal-type boundary will extend northwest of the low somewhere into Central New York. Moderate to heavy snow will continue through the afternoon near this boundary.
This boundary will likely drift westward through the afternoon as it weakens, spreading light snow showers back into the central and western Finger Lakes, including for some areas that had seen the snow stop.
Additional significant accumulations are expected over the eastern Finger Lakes and especially Central New York during this time period while areas further west only see an additional inch or so.
The exact location of this boundary is uncertain and could have major impacts on the accuracy of the snow accumulation forecast over the eastern Finger Lakes and Central New York.
Strong winds will begin to focus over the eastern areas while tapering off some further west. Still, significant travel hazards will exist with blowing and drifting snow.
By Friday evening, the entire region should taper to lighter snow showers with little to no additional accumulation.[wp_ad_camp_1]
Despite its uncertainties, this storm is very likely to be a high-impact event. There is some bust potential, where temperatures remain just warm enough for mostly rain and only minor snow accumulations. There is also potential for the storm to overperform with widespread amounts over a foot.
The above forecast is not based on any single computer model, but a blend of data with a heavy dose of personal forecasting experience and represents my best shot at what will happen.
The geographic labels I use, such as “western Finger Lakes” are vague and intentional. They are meant to give a general sense of the overall storm patterns, not to nail down specifics on a town-by-town basis. For that, please check your zip-code forecast or ask me for clarification.
I plan to have a live video update and question-and-answer session Thursday evening at 8:15 PM-9:15 PM. Please feel free to message me or comment with your questions before then as well though.
I will also have a blog post update Friday morning.
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