Good morning!
Here’s a look at our incoming storm. Note that amounts may shift a bit – read on for more details.
Hazards: Heavy snow causing travel disruptions. Gusty winds will cause a risk for isolated power outages, as well as potentially some periods of blizzard conditions.
Timing: Snow begins in the early morning hours Saturday before sunrise. The heaviest snow will occur from late morning/midday into the evening hours, winding down by late evening and ending completely by midnight.
Amounts: This is where the forecast gets interesting. As of now, my forecast is for 10-18″ of snow for much of eastern Massachusetts, with less to the west. This will be a very fluffy snow, so the snow totals will likely be a bit higher than the normal 10:1 snow ratios you may see on some model projections. I will discuss the model uncertainty in the next section, since these amounts may shift a bit.
Uncertainty: Where do I begin with this section?? The only truly certain thing is that we will (probably) see over 6 inches of snow as a coastal storm strengthens passing off the southeast coast of New England. One major model suite – the GFS and its ensembles – have a storm track further to the snow, which would give us less snow and a more run-of-the-mill snowstorm. (A run of the GFS last night had us getting almost nothing, with its ensembles having a similar idea).
However, every other model (and associated ensemble models) has us getting at least 9″ of snow. I don’t think the GFS is handling some of energy that will cause this storm very well, given the gulf between it and other models. It can’t be fully ruled out, of course, but I’m going with the model consensus of a more westerly track. However, some models are more to the west than others. Once you adjust for higher-ratio snowfall, some models project the potential for over 2 feet of snow, with others calling for a more modest but still sizable snow in the 10-15″ ballpark for the Lowell/Dracut area.
Still another point of uncertainty that follows this line of thinking is the western edge of the snowfall, and how sharp it will be. This likely won’t matter in eastern MA and southeast NH, but it may be an issue for the forecast in central/western MA and southwest NH. It’s possible that the western snowfall gradient could be a lot tighter than my forecast shows; this is a point of contention where there isn’t a consensus among models.
The long in the short here is that a massive snowstorm isn’t off the table and neither is a run-of-the-mill snowstorm, but right now I think a middle-of-the-road solution is more likely.
I’ll update this tonight as necessary.
-Nathan Coram
UML AMS Co-President