Forecast discussion: A high pressure system over New Hampshire is helping to keep our weather dry, but just for a few more hours. Boston will be seeing a mix of wintry weather for about 12 hours, before we change back to plain rain. Due to the bad weather arriving, the National Weather Service issued a Winter Weather Advisory west of Boston from 11 p.m. Sunday evening until 1 p.m. Monday afternoon. This is going to make driving during the morning commute treacherous.
Right now, radar imagery shows a batch of snow showers just passing into southwest Rhode Island. By midnight, we should see the first snowflakes arrive. Light snow will continue to about 4 a.m., before mixing in with some sleet and freezing rain. We will changeover to showers and light rain by 9 a.m., and will continue before ending as showers later this evening.
We will remain overcast into Tuesday morning, as a weak cold front offshore will bring some moisture up into Southern New England. We will see some snow showers late Tuesday morning and continuing into the mid-evening hours. I am not expecting any heavy snowfall, but a coating is possible.
Once we get into Tuesday evening, our weather is going to change. We will see drier weather, thanks to a very strong high pressure system. However, it will also bring a cold dome of air from Canada over New England. Temperatures during the daytime hours after Wednesday will barely make it to freezing. Overnight lows will be in the middle teens to lower 20’s. The dry weather will last until the end of this week.
The computer models are unsure about how to handle the weather after Saturday night. The American model sees a low pressure system developing from eastern Texas, bringing moisture all the way into Southern New England by Sunday afternoon. With the very cold air above us, the precipitation would be snow. We could see some light snow by Sunday afternoon. However, some models feel the high that was protecting us will push the moisture back to the south. Right now, my overall confidence on the forecast after Saturday night is very low.
72 hour forecast:
Tonight: Light snow to begin around midnight, and continue into 4 a.m. By then, we will see a mix of snow/sleet/freezing rain. I’m expecting a low temperature of 28. We could see 1-2 inches of snow south of the Mass Pike before the changeover.
Monday: Sleet/snow/freezing mix changes to rain by 9 a.m. We will see plain rain by about 2 p.m. We will see a high of 40 with east-southeast winds of 11-14 mph.
Monday night: Showers end by around 10 p.m., but remaining mostly cloudy. We will see a low of 32 with winds shifting to the west-southwest at 10-13 mph.
Tuesday: Overcast skies during the morning with snow showers during the mid-morning to mid-evening hours and a high of 38. Accumulations will be a coating to a half-inch.
Tuesday night: Partly cloudy with a low of 25.
Wednesday: Mostly sunny with a high of 34.
Wednesday night: Clear skies with a low of 22.
Thursday: Mostly sunny. Highs 28-31, lows 17-20.
Friday: Mostly sunny. Highs 30-33, lows 17-20.
Saturday: Partly to mostly sunny. Highs 27-30, lows 18-21.
Sunday: Cloudy with possible light snow by the afternoon. Highs 31-34, lows 12-15.