By James M. Arnold, Weather Specialist
Our storm continues to move toward us and will be here in full force tonight.? The light snow that has been falling for some time now is not directly from our approaching storm, but is from atmospheric upward motion related to the arctic front that lies just to our north. The front will slowly move to the south and bring its steadier snow along with it during the balance of the afternoon.? It looks like we will have from 2 to 4 inches of snow on the ground by the evening commute, when the snow shield from the storm itself will overspread the area.? There are still a number of wildcards at play as we try to figure out exactly how much snow will fall in this storm.? Some recent modelling is depicting two centers of low pressure; one that will pass out to sea southeast of the benchmark but still influence our weather.? The second one will likely come a bit closer to our area as it is considerably to the west of the first one and the trough related steering currents are hinting at a turn more to the north as the trough takes on a slightly negative tilt.? There is also the question of how much and how far inland will ocean enhancement of the snow extend and lastly, where does the coastal front set up.
Once under the snow shield of our storm we can expect snow to increase in intensity during the early evening hours, but likely after most of the evening commute is finished.? Overnight, snow will occasionally become moderate to heavy into Friday morning before tapering off during the mid- morning hours and ending by about noon.? I think we could be looking at another 6 to 10 inches overnight and another inch or two before the snow ends late tomorrow morning to around noon.?? A snowfall range of 10 to 15 inches looks to be pretty good from this event, but it will be hard to measure because to the powdery nature of the snow and the strength and duration of the wind.? I am comfortable with the wind ideas, that sustained speeds of 15 to 25 mph and gusts to 35 or 40 mph will occur overnight and early tomorrow morning, causing considerable blowing and drifting of the snow and possibly periods of whiteout conditions.? Travel will become very difficult overnight and tomorrow morning.
As emphasized in earlier statements, perhaps the most serious hazard over the next 48 hours is the cold.? Right now it is 9 degrees at Worcester airport and 11 degrees at my home and the temperature is falling slowly.? It will grow colder during the afternoon and overnight hours, with air temperatures likely nearing zero degrees by dawn tomorrow.? Temperatures will rise little tomorrow and will begin to fall again during the afternoon and overnight hours, reaching as low as -15 degrees in area cold spots by Saturday morning.? Most of us will see temperatures of -6 to -12 though.? These temperatures, driven by a brisk wind, can cause frostbite in less than a half hour and freeze unprotected extremities in a relatively short period of time.? Here is a link to some good cold weather information:
http://www.healthunit.org/hazards/Cold%20Weather%20Response%20Plan.pdf
James M. Arnold is a Weather Specialist working with Shrewsbury Emergency Management Agency; town of Princeton; Worcester Emergency Communications and Emergency Management Agency; Southborough Emergency Management Agency; town of Grafton and Wachusett M