As you have no doubt heard, its going to be cold Saturday night and Sunday morning! If the actual temp drops to -6 in Boston and -12 in Worcester, and that seems likely, we will set the record low for Valentine’s Day. Those records have stood since 1934 in Boston and 1979 in Worcester. Temps did drop a bit below zero around this time last year, but not that cold. In fact, -6 in Boston and -12 in Worcester would not only set records but both of those numbers would be the coldest at any point since January 2004. With winds around 20 mph sustained and gusts over 35 likely, it will feel even colder, more like -20 to -30!
Most of that you probably know. Here’s where the forecast gets interesting…there could be some ocean effect snow for the outer Cape! Normally to get ocean effect snow, you need the wind to be blowing over as much ocean as possible. A wind from the north is good. A wind from the northeast is better. Winds Saturday night will blow in from the northwest. That means the wind will only briefly blow over Cape Cod Bay before hitting the outer Cape. Not ideal. However, the winds will be plenty strong enough, and the temperatures are insane! The air temperature is unusually cold, even by New England standards! That means there will be about a 70 degree difference between the water surface temperature and the temperature a few thousand feet up in the atmosphere. That kind of energy in the summer would produce strong to severe thunderstorms!!! Ocean effect snow becomes likely when there is just a 30 degree difference between the water and the air a few thousand feet up. So the incredible instability should overcome the less than ideal wind direction. A coating to 2" of ocean effect snow seems likely for the outer Cape with a spot or two getting up to 4" by Sunday morning in the right circumstances.