In a winter that's on-pace to provide one of the least snowy winters on record for the Boston area and much of Southern New England, any chance of significant snow gets folks excited, anxious or curious. As such, I'm receiving lots of questions about Saturday's snow potential.
In Wednesday night's weathercast on NECN, we looked at the players involved: an arctic front marking the leading edge of a strong surge of cold air crossing New England Saturday, an energetic disturbance lifting northeast from the center of the country, and an active subtropical feed of moisture and energy available to our south. If all three of these come together, you get a big storm. If two come together, you get accumulating snow. If they all come at you but don't link up, you get snow showers. At this point, some interaction of at least the northern cold air and Central US energy looks likely on Saturday. I can also tell you, however, that right now the timing on getting more southern moisture involved is just a little out of sync with the other two disturbances, meaning a big storm remains a low probability at this point. That said, a small change in timing on the arrival of these disturbances would make a significant storm more likely.
So...here's what I can tell you:
- High confidence that snow will fall
- Moderate confidence that road treatments/plows will be needed in much of New England Saturday
- Low confidence on exact amounts - early estimate map below
- Start time Saturday sunrise, end time around sunset
- Blast of cold air follows for Sunday
Interestingly, the method of precipitation and snowfall estimate that proved so successful from days in advance in several events last winter, is indicating at least six inches for most of the Hartford, Providence, Boston, Worcester, Portsmouth and Portland corridor. That said, this method is based upon computer guidance precipitation estimates, and though current forecasts are quite moist, I am unwilling to bite on more than 3"-6" given the inability for multiple stream phasing of disturbances to occur in the forecasts. If I see a trend toward multiple disturbances phasing, I'll be more inclined to believe estimates of as much as 10" in the Boston area. For now, my best estimate is in this map...highest amounts in Southern/Eastern New England, lowest in Northwestern New England.