Ugly...
63, 73, 54 and 49...those are the high temps for Boston over the last four days. You see the trend...going down! A coldfront lies just south of New England and winds are now out of the NE blowing in cool, moist air off the water...temps will fall through the 40s because of that. Unfortunately they won't stop there...strong high pressure located in Central Canada is building SE towards New England...cold surface air in the 30s is working into Northern New England now and will continue to drain south through the night. There is also some very dry air located a couple thousand feet above the ground and when precip falls through that layer, it will cool below freezing. This sets the stage for a messy Winter-like storm here in the Northeast late tonight and tomorrow.
Most locals in Southern New England will be just mild enough to prevent significant frozen precip...cold rain mixed with sleet will be the rule of thumb. But in Northern MA and elevated areas and certainly Northern New England, sleet, freezing rain and even some snow will hang on longer and will accumulate. A coating of sleet is likely in Worcester County and near the NH border with a few inches of snow and sleet accumulating up north. While the rest of us get mostly rain, I do expect sleet pellets to mix in during the morning hours...even in Boston! Wind will also be increasing through the day out of the ENE...rain will blow sideways too...fun!
The storm will lift out Friday night as the rain tapers off and partial sunshine is expected over the weekend with more seasonable temps in the 50s. While it will be mainly dry, a brief passing shower can't be ruled out either day.
Marathon Monday still looks very pleasant...after a chilly start in the 30s temps will warm to around 60 under a mostly sunny sky. There is still a chance of a seabreeze slowing some of the later runners to cross the finish line.
