It’s going to be a long, drawn out, painfully slow arrival. The primary low is super far south for a big snowstorm.
Indeed, the initial brush from this storm will be unimpressive. Minor coastal flooding, wind gusts over 40 m.p.h. and periods of light snow will be common. The snow likely will struggle to accumulate in the valleys but in the hills an inch or two may add up tonight.
By tomorrow evening, however, this storm is going to get interesting. The large cut-off way south is going to do a fujiwhara dance with a diving (and strengthening) low from the Great Lakes.
With the circulation from the existing low in place with a strong low level jet and TROWAL signature the low that dives south toward us is problematic. Strong quasi-geostrophic forcing will act to “pull” northwest the precipitation shield offshore (this won’t happen physically but it may look like it on radar). Decent snow growth per BUFKIT soundings may promote some big fluffy dendrites overnight.
At this point we’re expecting 2″-4″ of snow tomorrow night but this is the kind of event that can really surprise. Both up and down. While the deterministic forecast we’re showing tonight is the same as last night (3″-6″ total basically statewide) I’ve bumped up the probability forecast quite a bit. Much more confident tonight than last night. I’ve also included low end probabilities of a more substantial snow 8″+ or 12″+ in case tomorrow night’s snow has some banded surprises for us.