Model Disagreement

A pleasant, light snow fell for many hours today at the GSD office. Because of the temperatures above freezing, the snow mostly just stuck to the grass and trees and did not impact the day in a meaningful way.

With temperatures on the decline, black ice could be a concern tomorrow morning in the usual places.

Now all of our energy is focused on the big coastal storm. The good news is that plenty of cold air will be in place for snow. The typical snow-to-liquid ratio is 10:1 but for this storm forecasters are expecting 12 or 14:1 to rations. No matter how much snow we get, those higher ratios means we'll see a fluffy, light snow that should be relatively easy to shovel.

NWS-Albany's first crack at a snow map for Wednesday/Thursday.

The bad news is the models are all over the place. One North American model is predicting much lower precipitation amounts. Another is predicting a direct hit for the Berkshires (12-16"). The crowd-pleasing Euro has strong precipitation values but takes the track of the storm to our south. We've even checked in with the Canadian model and that one also keeps the storm slightly to our south.

Here's one North American Model...

...and here's the other. This is what happens when the models can't decide on the track.

So, what does this mean? 

We think that South County has a much higher chance of 6+ inches of snow. The NWS has already issued Winter Storm Watches for Litchfield (CT) and Duchess County (NY), and it's likely that Berkshire County will get a Watch at some point tomorrow.

Because there likely will be a strong cutoff line--where the cold air blocks the northward moving moisture--we could easily see a situation where Sheffield, Otis and Sandisfield see 10" and North Adams, Clarksburg, and Williamstown only get only 3". Pittsfield would split the middle. 

We are definitely trying to gather as much information as possible to help us better understand just how high that cut off line will be. If the line moves into southern Vermont, all of Berkshire County will be over 6 inches with 12 for towns closer to Connecticut. 

Hopefully by Tuesday night we will have more definitive information for you. The one aspect of the storm that is more certain at this point is the timing of the start of the snow: late Wednesday night.