The following discussion and outlook covers metro Boston, North Shore and western suburbs: Areas of low pressure across the Ohio Valley extending to the East Coast will merge into one formidable ocean storm south of Nantucket Island by late tonight. As expected the area had a fresh coating of snow for the morning commute and the snowfall rate will be generally light throughout the day. It will be tonight and Friday morning when we start to get into the teeth of the storm as the gale center takes shape over the outer waters.
Not only should the snow remain light through the day it may actually become off and on again for a time. By evening a general 2 to 4 inches of snow should be on the ground. The action intensifies tonight into early Friday with windswept snow, heavy at times, drifting and blowing snow, gusty winds to perhaps 45 mph along the coastline and significantly reduced visibilities. Near blizzard conditions will likely exist later tonight toward Friday morning, making for difficult if not near impossible travel. This will be most significant along the coast where the highest winds and heaviest snow falls. An additional 4 to 8 inches of snowfall through the overnight hours. A Winter Storm Warning remains in effect until late Friday morning. When all is over with most will have 9 to 12 inches on the ground, with up to 14 inches possible along the coast, perhaps even locally higher amounts there.
Conditions improve Friday afternoon as the snow diminishes and comes to an end. Blowing and drifting snow will continue as this will be a very light powdery snow due to the very cold temperatures throughout the event.
Those temperatures do not get out of the upper teens today, fall to the single digits inland to around 10 on the coast tonight and don’t budge much on Friday. Highs in the low teens at best. With gusty winds through Friday we are going to be dealing with wind chills of 15 to perhaps 20 below zero into Saturday morning. The weather service states Wind Chill Advisories may be issued later today through early Saturday.
Coastal flooding is a major concern, especially for the high tides cycle around midnight tonight and midday on Friday. Although areas of usual susceptibility along the south shore are most likely to experience coastal flooding the threat remains along the north shore as well. The National Weather Service has a Coastal Flood Advisory in place for the midday high tide Thursday, with a Coastal Flood Warning for the following two high tides, around midnight and then midday Friday. Minor coastal flooding, with pockets of moderate flooding are possible. Again, areas south of Boston may see widespread moderate coastal flooding with Friday’s midday cycle being the biggest concern.
Saturday starts with sub zero temperatures just about everywhere, however with a southwest flow kicking in the thermometer recovers nicely into the 20s and with lighter winds it will actually feel comfortable in comparison to today, Friday and into early Saturday morning.
Updated Storm Outlook:
Thursday: Light snow through the day, could be intermittent for a time. Accumulations of 2 to 4 inches by evening. Cold, high temperatures upper teens. Increasing northeast winds may gust to near 35 mph this afternoon along the coast, 20 to 25 mph inland.
Tonight: Windblown snow creating blowing and drifting snow and reduced visibility. An additional 4 to 7 inches of snow likely, locally higher amounts right along the coast. Lows around 5 inland to 10 on the coast. Gusty north winds 40 to 45 mph likely.
Friday: Snow tapers off by midday and ends in the afternoon. Partial sunshine possible late across far interior. Windy and bitterly cold. Highs only in the low teens, close to 10 inland. North to northwest winds 20 to 40 mph, diminishing late.
Friday night: Partly cloudy, very cold and windy. Lows 5 to 10 below inland, zero to 5 below coast.