The morning commute looks ugly. There’s really no other way to describe how the weather looks early Wednesday with heavy snow changing to sleet and freezing rain. Our forecast really hasn’t changed since Sunday night – we’ve managed to stay remarkably consistent. Now let’s hope that consistency will pay off!
This is a classic Schwartz-Ekster SWFE (southwest flow event) with a deep layer of southwesterly flow in the mid troposphere with weak redevelopment at the surface just offshore to lock in the cold in the boundary layer. As always the issue is timing the arrival of the warmer mid level punch which will dictate the changeover from snow to sleet to freezing rain.
Synoptically, these storms aren’t particularly complex. A strong jet streak over southern Quebec puts New England in the right entrance region. Indeed, quasi-geostrophic forcing from differential cyclonic vorticity advection and strong warm advection in the lower troposphere will lead to strong synoptic-scale ascent across the region. Heavy precip is a lock!
These events generally don’t surprise a whole lot and have a pretty steady gradient in snow totals based on latitude. I do think one area where this may overperform (relative to SWFE climatology) is in the Route 2 corridor of Massachusetts up into southern Vermont and New Hampshire thanks to a bit of extra frontogenesis/deformation on the backside of an 850mb low that closes off.
Here in Connecticut – latitude will play a role in terms of snow amounts with areas to the north staying colder AND having better snow growth through the first portion of the storm.
Interestingly, the CIPS analog guidance shows a number of systems that have been decent snow and freezing rain producers. Take a look at the median snowfall and probability of >6 hours of freezing rain based off the 15 most similar analogs to tomorrow’s storm.