Metro Boston, North Shore and Metro West: Don’t let the mild temperatures and rain fool you this evening because weather conditions will change abruptly tonight as very cold air starts to overspread the region on strong northerly winds. The changeover from rain to snow will transition from northwest to southeast later tonight through the early morning hours reaching the coast before dawn. There could be a period of sleet and freezing rain during the transition to snow.
Temperatures in the 40s this afternoon are expected to plunge into the teens and low 20s after midnight. A rapid drop in temperatures are expected as low pressure moves to our east and drags the colder air in behind it. While areas across central and especially northern New England received heavy snow today it was too mild locally for wintry precipitation. Spotty showers broke out during the afternoon with a few embedded heavier showers into the early evening. Rain should become steadier tonight before the transition to the wintry precipitation occurs. A coating of snow to an inch is possible in and around the immediate Boston area with 1 to 3 inches probable elsewhere through Thursday morning. A few spot 4 inch totals are not out of the question, especially along and west of Route 495. Lowest amounts closer to the coast.
Thursday mornings commute could be tricky since any standing water from the rain will have frozen solid with a coating of snow and some ice on top of that. Areas that are not treated could become very slick and will be hidden by the layer of snow and ice from tonight’s changeover. Snow showers are likely to continue through a good portion of the morning hours then taper off an end in the afternoon. Do not expect temperatures to climb much on Thursday. The mercury will not recover from the morning lows and most likely only top out in the low 20s. They may not get out of the upper teens for some. That is about 25 degrees below normal. And, strong northwest winds that could gust upwards of 40 mph to possibly near 50 mph will add insult by reducing wind chills to the single digits to as low as zero during the day. The cold only gets worse Thursday night as we could break the all time record low for March 14th on Friday morning. That record was set in 1896 and is 12 degrees, which is just about where the lows are currently forecast for Boston. So, we take a giant step backwards Thursday to January or February. Take your pick.
The good news is that after a very cold start on Friday the mercury recovers into the low 30s during the afternoon. Although that remains some 10 to 12 degrees below normal it will be one heck of an improvement from Thursday and Thursday nights brutal cold.
Short Term Outlook:
Tonight: Rain will transition to sleet and snow around and after midnight from northwest to southeast. Areas of freezing rain are possible for a time. Early night temperatures in the low 40s will slowly fall through the 30s later tonight, then quickly drop into the mid teens to around 20 degrees during the early morning hours. Strong northerly winds will increase to 20 to 30 mph with gusts over 40 mph after midnight.
Thursday: Early snow to snow showers, tapering off an ending by afternoon. Very cold and windy. Near steady temperatures hovering near 20 degrees. Northwest winds gusting to over 40 mph.
Thursday night: Bitterly cold and windy. Record lows possible as the mercury crashes to the upper single digits to low teens. Strong northwest winds will drag wind chills well below zero overnight.