FINAL CALL: Get your engines ready folks. We have got ourselves an old fashioned daytime snowstorm on our way for all day tomorrow. The model output this evening is really bullish for significant snows east of ORH-FIT. Oddly, eastern MASS will do appreciably better than western MASS because the cold air is draining in on a NNE flow and it gets to eastern sections before western sections. That is why by noon tomorrow it should be snowing moderately to heavily in the city of Boston, while Albany, NY may be raining or having a wintry mix. You may not think that a snowstorm is on the way with temperatures this evening near 50F in Boston and in the 40s in the suburbs. However, that cold air will advect by the time this gets going here in eastern MASS by sunrise. I wouldn't be surprised if this started as a little rain in many locations, but it will quickly transition to all snow in many areas NE of Worcester and north of say, Brockton. This is when it could come down at a pretty good clip, perhaps 1"/hour snows for a while tomorrow afternoon.
Snowfall amounts will be greatest the further north and east you go. For the Boston metro area, I'd guess that anywhere between 4-7" will be the rule with a few spot 8" amounts in SE NH. Down over SE MA and the Cape, it is more of a 1-3"/spot 4" amount of snow if that inverted trough squeezes out a couple more inches than projected, which is a known bias of this type of setup. That is why I would not be surprised if some towns come closer to the higher end of my ranges, but for now, to be safe, I'd go with the lower end of the ranges for snowfall amounts. This is going to be a changeable situation and it will turn into a nowcast event to see where that rain/snow line sets up and how long it takes to come through a given area. Here is a rule I am going to use. If it is snowing in the city of Boston with a temperature of 33F or lower, then you can bet your paycheck that Boston will see 3"+ tomorrow. One computer model has Boston getting around 7" of snow tomorrow, with its nearby NW suburbs (Burlington-Newton-Melrose-Wilmington-Reading) getting up to 8-9" of snow. I do not think this will happen, but it is a possibility that higher amounts are realized in the greatest area of convergence in NE MASS, where the inverted trough snows could be quite intense as this system wraps up and moves its precipitation offshore.
School delays/cancellations? There will not be any need for delays. It will be a closed call or no call. I'm going to side with SCHOOL IS SESSION for most as many news outlets are forecasts light amounts, not ready to pull the trigger on a real significant snowstorm after a weekend of mid 60s Saturday and 60 on Sunday. But it's New England! Some schools will realize their mistake tomorrow afternoon in say the North Shore of MASS and southern NH, looking out their windows to visibility under a 1/2 mile in moderate to heavy wet snow and then go "Shoot!" Then we will start to see early dismissals. That's my call. Our next chance of snow comes Tuesday night/Wed. AM as a warm front moves through and then the rest of the week looks chilly with highs in the mid 30s into the weekend. Winter is not over yet!