Dense fog has moved in Sunday afternoon and evening as warm, moist air moves over the snow-covered ground. Temperatures are climbing, finally, into the 40s and 50s in southern New England. The fog is limiting the visibility at times to below a quarter of a mile. Where temperatures are near freezing or below, the low-level moisture is freezing on cold surfaces creating freezing fog and areas of black ice.
A cold front is pushing through New England Sunday night. This will help to trigger another round of showers with some locally-heavy downpours, especially across Connecticut, Rhode Island and southeastern Massachusetts. Gusty winds from the southwest could accompany the passage of this front, especially at the south coast. Once the front is offshore, temps will drop back into the 30s overnight. Lows will drop back into the 20s north overnight, with some partial clearing. Watch for black ice near dawn!
Monday will be a dry, cooler and blustery day. West-northwest wind gusts of 30 to 40 mph are expected throughout the region. A few snow showers or snow squalls will be possible in the northwest mountains, which could briefly reduce visibility and give some localized heavy snowfall - very isolated. The breezy northwest winds will usher in much colder air for Monday night into Tuesday.
Tuesday starts out cold and dry with lighter winds, with high pressure sitting near us. Highs on Tuesday will average in the lower 20s, which is quite cold for this time of year! We will also track an Alberta Clipper, which will bring accumulating snowfall south of the Great Lakes to the Mid-Atlantic and then track south of New England. It does not appear to be very impressive right now, but some deepening is expected off the coast. If it tracks close enough, we just may see a few inches of snow from this (one to three inches). The best chance of this would be right at the coast.
Wednesday is the day of the Arctic front! Winds start off light, but become gusty by afternoon from the northwest as this intense Arctic cold front will sweep across the region during the middle to late part afternoon of the afternoon. This is the leading edge of the coldest air of the winter, which will could help to trigger a few scattered snow squalls as it pushes through which could reduce visibility - hopefully not nearly as bad as what happened in New Hampshire on Friday, causing a 35-car pileup. Winds could gust 30-40 mph from the northwest by the end of the day, and temperatures will be dropping into the teens by sunset and falling below zero for most of New England Wednesday night.
Wednesday night through Thursday morning will be the time of the most extreme and dangerous cold. It is the kind of cold where limiting your exposure to the cold is a must. Too much time exposed to these extremes in temperatures can be life-threatening. It will be that cold. Northwest winds gusting to 25-35 mph all night Wednesday night will make temperatures feel -15 South to -40 in northern Maine! Exposed flesh can freeze in 30 minutes or less in these conditions.
An interesting fact from the National Weather Service says for Boston, a low of zero degrees will be the coldest reading in four years. It has only reached zero or colder twice in the past 10 years in Boston (2011 and 2005, when it was -2).
By Thursday, Arctic sunshine will be in place. Highs temperatures will be in the single digits - lower-mid teens in southern New England is all we will be able to reach. Another cold front will push through early Friday morning. This could come with a little light snow and help keep temperature running below normal into the weekend, but it will not be as cold as the bitter blast coming Wednesday night into Thursday.