Another cold front is approaching southern New England today. High pressure is positioned to the south of us. Ahead of the front we can enjoy a milder southwest flow today and tonight, although temperatures will still be running below normal. Sun and high clouds will share the sky today before the clouds win out overnight.
The front moves through here Sunday morning and may trigger snow showers or flurries as it does so. Behind the front comes another blast of cold arctic air for Sunday night, Monday and Tuesday. Also, the front slows and stalls south of New England Sunday night and Monday. Low pressure will develop along the frontal boundary well to our southwest, across the Tennessee Valley, on Sunday and is expected to be positioned in Virginia Sunday evening. It will then move rapidly northeastward to the southeast of Nantucket by Monday evening.
Although this is not expected to be a significant storm the further south of Boston you go the higher snowfall amounts will be. Light snow should overspread our local area early Sunday night and be with us through the night. But, the heavier snow falls over southeast Massachusetts and especially Cape Cod. With the storm track well south of us we expect the northern edge of the precipitation shield to move out early Monday morning north of the city, although snow continues into the afternoon toward Cape Cod. Arctic high pressure comes out of Canada and overspreads the region later Monday night and Tuesday.
For our forecast area, that is metro Boston and the northern and western suburbs, the further north you go the less snow there is going to be. It is likely there will be very little snow across northern Middlesex County and along the Merrimack Valley. Early thoughts on snow accumulations are 2 to 3 inches in the immediate Boston area, 1 to 2 inches north and west of the city. Perhaps only a coating along the New Hampshire border through the Merrimack Valley.
Behind the departing storm comes more cold air for Monday night and Tuesday.
72 Hour Outlook:
Saturday: Partly sunny and not as cold. High temperatures in the low 30s. South to southwest winds increasing to 10 to 20 mph this afternoon.
Saturday night: Mainly cloudy skies and not so cold. Lows in the mid 20s. Southwest winds may gust 20 to 25 mph, especially along the coastal plain.
Sunday: Mostly cloudy with a chance of snow showers or flurries, especially in the morning. Highs in the low 30s. Winds becoming northwest 10 to 15 mph.
Sunday night: Cloudy and colder. Chance of light snow developing. Lows in the teens. Winds turn north and stay light.
Monday: Chance of light snow early, otherwise becoming partly cloudy. Much colder. Highs only near 20 degrees.
Monday night: Bitter cold returns. Fair skies, lows in the single digits, near 10 along the seashore to low teens in Boston.