By James M. Arnold, Weather Specialist
Region – Here is an update as of Monday afternoon, Nov. 24, regarding a possible Thanksgiving Eve snowstorm:
Now it is just a waiting game as the storm approaches us from the southwest. It is hard to believe that after 3 straight days of temperatures in the high 50s and low 60s we would be looking at a major snowstorm. Only in New England.
There are just some minor changes to the recent string of forecasts, as the storm continues to behave pretty much as expected and The National Weather Service has extended the area for their Winter Storm Warning to the south and east to now include all of Worcester County and much of the adjacent counties further to the east. Rain and snow should begin about dawn tomorrow and with the relatively warm pavements, driving should be O.K. to start, but as snow continues it could become slippery toward the end of the morning commute. Visibility will also become an issue for drivers. Snow will pick up in intensity by noon and continue to fall at a moderate to heavy clip for the rest of the day and into the night, likely tapering off just before midnight and ending shortly after that, probably in the 1:00 to 3:00 A.M. period of Thursday morning. I think the estimated accumulations from the email of yesterday are good, and this storm will still be somewhat dependent on elevation for snow. The higher ground areas to the north and west of Shrewsbury, such as Paxton, Rutland, Holden, Princeton and points to the north and west will see the deepest accumulations as snow will fall for a longer period of time, perhaps for the entirety of the storm. Accumulations could be in the range of 10 to 15 inches in portions of this area and there could be a few isolated pockets of 18 inches reported, especially if the coastal front sets up in our area. In the Shrewsbury, Worcester, Leicester, and West Boylston areas, accumulations will likely be in the 8 to 12 inch range. Further to the east toward the Route 495 corridor, accumulations will taper off to 4 to 8 inches in the Southborough area and the same holds true for the areas to the south of the Mass Pike, where Northbridge and vicinity should be looking at 4 to 8 inches as well. One common theme throughout our area is that the snow will be of the wet and heavy variety, clinging to everything it falls on.
The coastal plain, Cape and Islands will see only a slushy accumulation if anything, as rain will make up the most of the storm. The NWS has issued a “High Wind Advisory” for the coastal plain, Cape and Islands for northeast winds potentially gusting to 55 mph. In addition a “Storm Warning has been issued for the offshore waters and a “Gale Warning” has been issued for the coastal waters. The reason for this is that as the storm moves up the coast it will continue to intensify, building a strong pressure gradient between it and high pressure to its north. With fairly high astronomical tides there is the threat of some significant east facing beach erosion at the time of high tide early Thursday morning.
There is little change in our wind expectations from yesterday. Though winds here will not be nearly as strong as they will along the coast, it could be windy enough over inland areas to cause damage to trees. Winds will increase during Wednesday afternoon and evening to 15 to 20 mph with occasional gusts into the 30 to 35 mph range throughout the night. This could be enough to break large, heavily snow laden branches off trees if not bring whole trees down with the potential to create scattered power outages and interrupt travel should they fall into area roadways.
The expected temperatures with this storm will begin in the mid to high 30s early Wednesday as the precipitation begins, but will begin to fall as the storm draws colder air in with intensification. In addition, these storms can create their own supply of cold air as the heavy precipitation pulls colder air from higher levels of the atmosphere into the circulation. These factors will serve to offset the lack of cold air in advance of the storm and help to cause a heavier snowfall in many areas. By early afternoon Wednesday our temperatures will sink into the low 30s and should stay there throughout Wednesday night. Thursday will likely see temperatures hold in the 30s as well, with partly to mostly cloudy skies and quite breezy conditions.
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 Mountain Ski Area