Confidence growing in slick and snowy Sunday-Monday

Wintry Scenario Setting Up

Winter weather has settled back into the Finger Lakes with cold temperatures and the threat for snow and ice later this Holiday weekend.

Before addressing the upcoming ice potential, be aware that area roads are slick this morning following Thanksgiving’s snow and rain. Pockets of freezing drizzle have only added to the slick roads. Conditions should slowly improve as roads are treated.

The remainder of today will just be a cloudy, quiet day. High pressure is building into eastern Canada but is still centered north of the Upper Great Lakes. This still has our winds from the north, causing lake effect cloud cover and the pockets of freezing drizzle.

High temperatures today will be near or just above 30 degrees.

This high pressure system will play a vital role in the evolution of our weather on Sunday. For Saturday though, the high will keep us dry with clouds and some sun. Morning lows will again range through the 20s with afternoon highs just above 30 degrees.

By Sunday, the high pressure will be entrenched over eastern Canada while a large, mature storm system tracks into the Midwest. The high pressure will not yield to the incoming low, setting up a messy Sunday for the Finger Lakes.

Snow & Ice Concerns

Precipitation will gradually work from southwest to northeast across the region in the hours before and after sunrise Sunday. This precipitation will be triggered by a warm front. However, with the high pressure continuing to supply cold surface air, any warming will take place above the surface.

This will result in a mix of snow, sleet, and freezing rain across the region. Snow is more likely the further north and east you go, while freezing rain is more likely to the south and west. Much of the region may end up with a prolonged period of sleet between the freezing rain and snow.

For reference, sleet falls as ice pellets, while freezing rain falls as liquid rain but then freezes on contact with the surface. Sleet is slick but can be shoveled and plowed while freezing rain turns into glazes or sheets of ice.

The biggest uncertainty is where the cut-offs between snow and sleet, and between sleet and freezing rain will end up. This is not likely to become certain before the event begins as this is a very complex scenario that will be highly sensitive to slight temperature variations well above the surface.

A secondary source of uncertainty is how much precipitation falls and how steady it will be. This should become clearer over the next 24-36 hours.

Travel Sunday anywhere in the region will be less than ideal, whether due to snow, sleet, or freezing rain. Plan for extra travel time if you are unable to make alternate plans, such as traveling on Saturday.

A secondary low pressure system will begin to develop off the coast of the Carolinas Sunday afternoon and evening. Combined with the high pressure system, this will cause the warm front to stall out and dissipate before it can move through the Finger Lakes.

This low will track north along the coast, pulling cold air back into the region at all levels of the atmosphere. Any precipitation that is still falling late Sunday afternoon and evening will turn back to snow.

The third uncertainty then becomes how far northwest this secondary low will spread snow. At least some snow should make it back into our region for the second half of Sunday night and early Monday. The Southern Tier and Central New York are most likely to see accumulations.

Snow amounts are still highly uncertain, and could range from a minor inconvenience to a significant disruption.

Snow should taper off later Monday as the low pressure system pulls away. Tuesday looks quiet before a quick moving system flies through the area late Wednesday with some snow. Lake effect will flare up behind this system for Thursday.

Weekend Update Plans

Here is when you can expect updates from Finger Lakes Weather this weekend:

• Saturday afternoon or evening (Snow/Ice Report for Sunday)
• Sunday morning (full blog post…this will be an important update as I analyze how the system is starting to unfold locally)
• Sunday evening (Snow Report for Sunday Night/Monday)
• Monday morning (full blog post)

Be sure you are on my email list for updates. Social Media is highly unreliable as their algorithms pick and choose what is “important” and may not show my updates…or will not show them until days later. You can easily sign up using the form below.

As I mentioned a couple weeks ago as well, your donations are extremely important to the funding of FLX Weather. I run this service completely on my own using entirely original forecasts that I make myself.

During large weather events on Holiday weekends especially, this takes a large amount of time and effort that goes unseen.

Many have generously signed up for monthly donations. If you are able to join them, even for just a few dollars a month, it would be greatly appreciated and will help me continue to give my all in your service!