For The Rest Of This Afternoon: Rain is expected throughout the rest of this afternoon and it is likely that the rain will be heavy at times. Temperatures this afternoon will gradually fall through the 40s.
Accumulating Snow Is Still Expected Tonight Into Friday Across All Of Western & Central Mass: We will be in a prime setup for a late season snowstorm across Western and Central Mass, especially in the higher terrain, tonight into Friday. With that said, this continues to be an extremely difficult forecast as the smallest differences in temperature, precipitation intensity and low pressure track will mean the difference between mostly all rain and a very significant snowstorm across much of, if not all of Western and Central Mass.
An upper level low pressure system now located over the eastern Great Lakes will track across southern New England during the day on Friday. The dynamics, energy and moisture with this upper level low pressure are quite strong and this will lead to the atmosphere to become colder tonight into Friday leading to a changeover from rain to snow. At the same time this is occurring an area of low pressure now taking shape off of the Mid-Atlantic coast will head for Nantucket on Friday. This will cause some extra energy and moisture to be pulled into this system.
Here Are My Latest Thoughts: A changeover from rain to snow looks to occur first across the Berkshires and across areas along and north of Route 2 between about 8 pm and midnight this evening.
By the period from midnight to 3 am or so tonight, a changeover from rain to snow is likely to occur in the Hilltowns of Western Mass, the upper Pioneer Valley of Western Mass and potentially across much of, if not ALL of Central Mass, including metro Worcester. Rain or a rain-snow mix is likely to be occurring across the lower Pioneer Valley, including the Springfield metro.
Turning to the period from about 4 am through sunrise Friday morning, a changeover from rain to snow will reach the lower Pioneer Valley, so that it will probably be snowing everywhere across Western and Central Mass by 7 to 8 am Friday morning.
During the day on Friday, snow is expected to continue across Western and Central Mass. The exception might be across the Pioneer Valley of Western Mass, where the snow will probably mix with rain at times.
The snow or the snow-rain mix will be heavy at times late tonight into Friday and this will lead to significant snow accumulations in areas that stay all snow.
All of the snow or rain-snow mix with this storm will come to an end between 9 pm and midnight Friday evening.
This is going to be a wet and heavy snowfall and therefore some power outages are possible in areas that see 4 to 5 inches or more of snow accumulation. In addition, roads will be snow covered and quite slippery tonight into Friday in the higher terrain.
In Summary, significant wet and heavy snow accumulations are expected across parts of Western and Central Mass (My latest forecast total snowfall map can be found below). Snow amounts are going to be highly dependent on how heavy the precipitation falls. Once again, I want to emphasize that this continues to be an extremely difficult forecast and the smallest changes in either the storm track, surface temperatures or moisture feed could mean the difference between mostly all rain for many and a widespread significant snowfall across much of the area.
One other thing to note is that there are some similarities of this storm to the March 31 to April 1, 1997 snowstorm and the October 29-30, 2011 snowstorm. Both storms and especially the 2011 storm brought much more snow than what was originally forecast. So, keep this in mind for tonight into Friday.
One final thing – I would greatly, greatly appreciate any reports tonight & Friday. This includes precipitation type and how much snow has accumulated at your location. This will make it easier for me to determine what is actually happening & will also help to facilitate the updating of the forecast, if necessary.
My Forecast Snow Total Map For Tonight Into Friday Can Be Found Below:
I continue to monitor this storm closely and will continue to keep you updated.