Feb 28, 2014

Sunday Night-Monday's Snow Threat

We're going to see snow during this time period, well at least some of us will. Latest data continues the trend of suppression of the area of precipitation toward the south. Cold arctic air is the reason why the area of wintry weather will more south versus north.

Right now most of the deterministic models bring measurable precipitation up to an approximate Buffalo-Saratoga Springs-Arlington, VT line. The image below is from the Weather Prediction Center's Winter Weather page. I tend to be in fair agreement with their forecast as it relates to the forecast probability of 1" snow fall by 7AM Monday morning 3 March. The area in green has a < than 30% chance of seeing 1" snow, the three blue bands are probabilities ranging from 40-50% across the CD, to 50-60% just to the south of the CD and 60% or better in the aqua blue across the central and southern Catskills Mid Hudson Valley east to the southern Berkshires.

What the above map also indicates is both the very sharp cutoff between accumulating snow and little or no accumulation and that areas to the south of Albany have a better chance of seeing more snow accumulation.

The snow probabilities for snow fall exceeding 4" range are shown below.
 The greatest probability for snow exceeding 4" is about 20% or so along the NYS Thruway-Mass Pike (I-90) increasing to 30%-50% across the Southern Catskills-Lower Hudson Valley- southern Litchfield County CT line.

Again any shift north or south of the lows track by as little as 30 miles will alter these above (threshold) probabilities either up (low tracks more north than forecast) or down (low tracks farther to our south than forecast so lesser snowfall).

While it is still way too early to come up with numbers, my confidence is growing that in terms of a general accumulation:

1)  areas now north of a Buffalo-Saratoga-Arlington line snow amounts will be very light and this area may not see anything at all.
2) Working south from this line at least a few inches will fall

3) with the potential for a moderate perhaps marginally heavy snow of  > 8" but less than a foot for the southern Catskills-Lower Hudson Valley, Southern Taconics

Needless to say things can change, regardless I and my colleagues will keep you posted on this system throughout the weekend.