Winter Storm Watches issued, but storm details remain highly uncertain

But First, Lake Effect Snow Update

Confidence is growing in a significant winter weather event for the Finger Lakes Thursday into Friday, but lake effect snow is also ongoing today, Wednesday.

A shift in the wind over Lake Ontario has sent the lake effect snow band to the south earlier than expected this morning. A spray of new flurries and squalls is developing behind the primary band which will continue to move southeast out of the region.

Flurries and squalls will continue from Rochester to Ithaca and in surrounding areas throughout the day, but the heaviest and most widespread lake effect snow will be this morning.

A couple of inches may fall in more persistent snow bands with a general inch or so elsewhere.

Outside of the lake effect, it will be a breezy cold day with partial sunshine.

High temperatures will struggle into the low 30s. With wind gusts over 30 mph, it will feel like the 20s.

An area of high pressure will move in overnight, ending the lake effect. Winds will reverse course and come from the southeast as the major coastal storm begins to take shape.

Difficult Forecast for Significant Storm

However, there remains a great deal of uncertainty in the details that will ultimately have a large say in what our region expects.

First, here is what I can say with a fair amount of confidence:

A strong coastal storm will develop. Precipitation will be widespread across the Finger Lakes as early as Thursday afternoon and evening. A lull in the precipitation will then be followed by a second round that will continue into at least early Friday morning.

The two main details that remain fuzzy are how the temperatures set up throughout the lower atmosphere and where a band of heavy snow will develop on the backside of the storm Friday.

I will take a great deal of time and effort today to resolve these uncertainties.

At this time, I would expect an inch or two of snow Thursday afternoon and early evening. This will then be followed by a period of light sleet, snow, and freezing drizzle Thursday during the late evening and early overnight. Several hours of moderate to heavy snow will then fall early Friday morning.

In a low-impact scenario, snow totals top out in the 2-4 inch range with some icy spots Thursday night.

In a high-impact scenario, the precipitation stays mostly snow and a heavy band sets up over the central and eastern Finger Lakes Friday morning. Some areas could approach or even exceed a foot of snow with this set up. This scenario is favored by the usually trust-worthy European by varying degrees.

I will hold off on a snow accumulation map this morning with the anticipation of releasing one tonight.

Stay tuned and be wary of weather hype! Watch for tonight’s update.