After a winter where we didn’t really have much snow, it does look like there is some more coming, for at least part of the region.
Some of you woke up to the ground being white this morning after a disturbance moved through with some snow and rain showers. Well, a similar occurrence is possible Saturday morning. A weak storm system will pass south of the region Friday night and Saturday. We’ll have some cold air (relative to mid-April) in place, with temperatures generally in the lower to middle 30s, especially north and west of Boston. As the system moves in, precipitation will develop late Friday night, and it will likely be in the form of snow north of the Massachusetts Turnpike. Light snow will fall through the early morning hours changing to rain across most of eastern Massachusetts, but possibly staying all snow from the Worcester Hills into the Monadnocks and maybe even southern New Hampshire before it ends during the afternoon.
It’s awfully tough to get accumulating snow in mid-April for a variety of reasons, but there are some things that will help this time. First of all, a lot of the snow will fall at night. Once the sun comes up, the sun angle is similar to late August, so it’s awfully tough to accumulate in the daytime. Second of all, temperatures will be close to freezing. Third, the snow may come down at a decent clip, which will help bring down a little bit of colder air from aloft. Working against accumulating snow is the fact that the ground is warm. There aren’t many sources for ground temperatures, and the nearest station is in Bennington County, Vermont, but even there, the latest reading shows a soil temperature of 37, which is 3 degrees above normal. On pavement, it will have an even tougher time accumulating, if it at all. Despite air temperatures in the 40s and lower 50s this afternoon, pavement temperatures are in the 60s and 70s, thanks to the sunshine. They’ll drop at night, but with air temperatures staying above freezing, the pavement temperatures will as well. Any snow that does accumulate should quickly melt Saturday afternoon and evening, as rain and milder temperatures eat away at it.
It’s also fairly rare to get accumulating snow in late April. The last time that Boston or Providence had 1″ or more in late April or May was on April 28, 1987! In Lowell, 1″ or more has been recorded after April 16 only 6 times in the past 92 years, and the last one was on May 18, 2002. This is why we never declare winter to be “over” in March or even early April. Having said that, we’re not convince this is the last time we’ll see any flakes this season either. Many members of the ECMWF Ensemble are signalling the potential for some flakes around April 28-29. Will it happen? We’ll see. For now, it’s something to keep in the back of our mind and pay attention to.
So, how much snow are we expecting? Not much. For those of you inside I-495, you’ll see some flakes, but there will be little to no accumulation. From the Merrimack Valley into Southern New Hampshire, a coating to an inch, mainly on grassy surfaces. As you get into the hills of Worcester County and the Monadnocks, some places could see 2-4 inches of accumulation.
We’re aware that many models are forecasting more snow than this, and over a wider area. However, the models are just tools, and knowledge an experience are a big factor in our forecasts. We explained why it’s tough to get accumulating snow at this time of year, and many of the models don’t factor that in. This is why you should always follow a trusted source for your forecasts. There are plenty of “Facebook Forecasters” out there who will just regurgitate the models, and gleefully tell you that 2-4″ or more is expected. Sure, it’s possible, but in reality, it’s not likely.
Another storm will pass south and east of New England on Monday, likely too far offshore to have much of an impact on us, but we’ll keep an eye on it anways. After that, as we mentioned earlier, we’ll keeping an eye on the period around April 28-29. Hopefully that doesn’t pan out and winter is truly over. However, this is New England, so who knows. For now, stay safe, and watch the snow fall Saturday morning.