Very cold air is in place this morning with strong high pressure to our north. Temperatures this morning start out in the single digits to low teens throughout the forecast area. With a developing low pressure system to our south the stage is set for a major winter storm to impact us later today and especially through the overnight hours.
Light snow breaks out by early to mid afternoon, although a few flurries may fall earlier than that. The snow remains on the light side through the afternoon but then begins to increase in intensity during the early night with periods of moderate to heavy snow making travel difficult through the night. Several inches of snow will fall during the overnight hours, tapering off around midday Sunday. Very late Saturday night and or Sunday morning we may see a mix to sleet most everywhere with the possibility of a period of rain mixing in along the immediate coast. It could even change to all rain for a brief time Sunday morning right along the coast. By the time any mixing or changeover occurs the majority of the snow accumulation will have taken place as it is expected to be very snowy through Saturday night.
The National Weather Service has issued a Winter Storm Warning for our area from mid day today through mid day Sunday. Snow will most likely accumulate 6 to 10 inches west of Route 128/95, possibly up to a foot just west of Route 495 with 4 to 6 inches inside of Route 128/95 to the coastline.
Also, the weather service has issued a Coastal Flood Advisory for possible splash over and some flooding of low lying roads in the usual prone spots during Sunday mornings high tide.
The storm center is expected to be near Nantucket Island around daybreak Sunday and then move quickly toward the Canadian Maritimes. In its wake we can expect improving conditions Sunday night and Monday but with more well below normal temperatures and gusty winds.
Another system approaches Tuesday and may trigger snow showers or a period of light snow at that time. It will remain much colder than normal for mid December.
72 Hour Outlook:
Saturday: Light snow overspreads the area through the afternoon. Much below normal cold continues, highs 20 to 26, coldest inland. Northeast winds 5 to 10 mph.
Saturday night: Snow intensity increases, possibly heavy at times. Sleet may mix in late, chance of rain mixing in on the coast by morning. Slowly rising temperatures to 29 to 35 late night into Sunday morning, mildest along the coast. Brisk northeast winds may gust to 30 mph, possibly higher along the coast.
Sunday: Snow, rain and sleet along the coast, snow and sleet inland, all winds down around mid day. Chance of snow showers in the afternoon. Windy and cold. Highs 30 to 36 early, temperatures falling back into the 20s later in the day. Winds backing to the northwest with gusts to 35 mph possible.
Sunday night: Partly cloudy, windy and cold. Lows 12 to 20 degrees, interior to coast. West winds diminishing to less than 15 mph.
Monday: Windy and cold with mostly sunny skies. Highs 22 to 26.
Monday night: Increasing clouds and very cold. Lows 9 to 15, interior to coast.