New England Daily Snow

Short Term Forecast

It's been a pretty tame month so far in New England with our last drop of decent precipitation for most areas back on January 2nd. The snow stake on the top of Mt. Mansfield in Vermont is certainly showing just how snow-less this winter has been so far with a meager 14" -- almost the lowest for mid-January in the last five decades.

Fortunately, the weather hasn't been too warm during this stretch with daytime high temperatures in the upper 20s, overnight low temperatures dropping back into the 10s and low 20s, and a fair bit of cloud cover. This has allowed resorts to crank their snow machines nearly non-stop for two weeks. There's lots of corduroy out there.... and with shots like these, it's not all bad:

That all changes tonight and into Saturday with a beast of a storm moving into the eastern U.S. We won't get the blizzard conditions they got in the Midwest, but we will pick up some rain (south) and snow (north and at elevation) out of this storm. Most ski resorts in central and Northern New England will see a net gain of snow come Sunday morning, with lingering snow showers.

Here's how I see the storm shaking out:

• It should be snowing across southern Vermont and the Berkshires by daybreak on Saturday morning.
• Snow should overtake the rest of Vermont and central/northern New Hampshire through morning with heaviest snow falling late morning through early afternoon in these locations.
• Snow will be heaviest in Maine later in the afternoon.
• Snow will mix with rain all the way up to the foothills in New Hampshire (up through exit 26-28 on I-93 and likely all the way to Conway on Rt. 16), within the Connecticut River Valley (up through the I-89 interchange on I-91), all of the Champlain Valley, and locations within ~25-50 miles north of I-95 in Maine.
• Precipitation should remain snow north of these regions and especially at elevations >2000', including most of the Green Mountains, White Mountains, and Longfellow Mountains.
• Everywhere changes back over to snow and snow showers overnight into Sunday with upslope snow continuing across Vermont and northern New Hampshire through Sunday.

This forecast is nicely summarized by the NAM below:

NAM forecast animation of sea-level pressure and precipitation type for Saturday from http://www.pivotalweather.com.

Snow-to-liquid ratios with this storm will be low, meaning that snow will be on the denser side and not exactly powder. The best shot at powder will be at higher elevations where temperatures will remain coldest throughout the event. Interested in knowing the details? Here you go: For example, in Vermont at ~12PM the best lift in the atmosphere will likely remain below the "dendritic growth zone" (where temperatures are conducive to formation of dendrites -- snowflaky snowflakes). Because of this, snowflakes will form at slightly warmer temperatures and take on ice crystal shapes that will pack more closely together as they accumulate, or even melt if the temperatures gets too close to 32F. As the storm pulls away and colder temperatures move back into the region, this changes the ice crystal formation back to fluffier snow. 

Accumulations will be tricky because of spatial variability in snow-to-liquid ratios driven by temperatures and elevation. Highest snow accumulations, and highest confidence in snow totals, will be north and at elevation, whereas any forecast for snow accumulation in the foothills and resort bases (say <2000') will be tricky. Here's a summary of how I think it will accumulate:

• Valley locations <1000': 1-2", change to rain, then back over to snow.
• Elevations 1000-2000': 2-3", mix with rain, then back over to snow
• Elevations 2000-3000': 6-8", mostly all snow
• Elevations >3000': >8", all snow
• Elevations >4000': >12", all snow

Below is the OpenSnow forecast snow totals using propriety blends of models and snow-to-liquid ratios for our New England resorts over the next five days through Tuesday (includes both storm snowfall and any upslope snows). Highest totals will be in the highest elevations of the White Mountains and in western Maine with a sharp cutoff to southern, easter, and lower-elevation resorts.

Extended Forecast

Snow showers will linger across Vermont and New Hampshire through Monday before backing off Monday night. Tuesday is a weak transition day where we'll see high pressure and some sunshine before clouding back over Tuesday night for another round of light snow on Wednesday morning.

ECMWF forecast animation of sea-level pressure and precipitation type for Wednesday from http://www.pivotalweather.com.

We then will likely get another break early on Thursday before a second round of light snow possible on Thursday night of next week.

NAM forecast animation of sea-level pressure and precipitation type for next Thursday night from http://www.pivotalweather.com.

Should the forecast hold and not dry up, each of these light snow events next week will be capable of dropping ~2-4" of snow with higher amounts (at least as of today) coming from the Thursday night storm. That would push our 7-10-day forecast snowfall amounts well over 1 foot almost everywhere across central and Northern New England, with some spots pushing 2 feet:

I'll close the forecast today by saying that the GFS model is less bullish on snow for next week than the ECMWF, shown above. The GFS still produces pretty good odds of light snow next week, but doesn't have the same energy that the ECMWF has and thus lighter snows.

I'll most likely have an update on Sunday with a storm round up -- which should also be a great day for skiing in the Greens and Whites (just head to the top half of the mountains). If the forecast changes significantly throughout the day Friday, I'll push another update on Saturday morning.

-Dr. Jay | New England Daily Snow