I will be the first to tell you that this storm is killing me. I don't know what to expect. This setup should send us a mostly rainstorm, but that is not what the models are showing. In fact, temperatures just outside of Boston may never get up over 32 degrees. This Arctic air that moved in early this morning means business. My high today was 21 degrees. Right now, I'm sitting at 16. This cold air is really going to help us in regards to snow. Once the precipitation starts, evaporational cooling will take effect and everyone will start as an initial burst of heavy snow. By 3AM the snow should start here in eastern New England and by 5-7AM the snow will be falling heavily. Snowfall rates early Sunday will be on the order of 1-2"/hr. This will allow the Cape and Islands to maybe see that 1-2" on the first hour of snow. Winter weather advisories are up for the entire state south of the Pike, including Boston and the coastline for a general 2-5" near Boston to 1-3" south. North of the Pike, a winter storm warning is in effect for a general 4-8". The mountains will do well with over a foot.
I pushed the snow lines further SE from my earlier thinking. It will now be going into nowcasting mode and watching observations. It will be a tough forecast. Lets get through this one and then next week will be much more quiet. Beware of the flash freeze tomorrow night. Whatever slush is on your driveway tomorrow night will be there for quite a while.
Updates tomorrow with observations and radars. Its going to be a wild ride. Oh yeah, winds up to 60mph tomorrow afternoon with heavy wet snow could lead to power outages north of the Pike. Keep that in mind. Have your generator on standby for the 1PM kickoff of the Pats and Jets.