Could it actually snow in NYC next week?

Forecast model data suggests that a coastal storm will pass south of the area on Tuesday, with cold air pushing in during the storm and leading to the potential for winter weather. Inconsistencies on model guidance with the track and intensity of the storm are leading to an unusually low confidence forecast. 

After all of this time, and with temperatures in the lower 50s this afternoon, it may seem surprising that we’re discussing a winter storm threat now. The airmass in place across the area today is quite warm, but the pattern is changing around us and colder air will begin to press towards the area this weekend. The coldest air will still be well north of the area in Canada and New England, but there’s just enough present for us to pay attention. 

Forecast guidance is keying in on a disturbance developing through the Mississippi River Valley early next week, eventually tracking northeastward towards the region. This disturbance will lead to the development of a surface low pressure along the Mid-Atlantic coast by late Monday and Tuesday. Lift and moisture from this system will bring precipitation into the area by Tuesday. 

Initially, the airmass is still somewhat stale. It isn’t necessarily warmer or colder than normal, just stale. The storm approaching our area is being driven by a process called warm air advection, which is exactly what it sounds like – the advection of warm air. This leads to concerns for mixed precipitation or rain with the initial sequence of the storm system on Tuesday.

As time goes on Tuesday and Tuesday evening, guidance suggests the low pressure to our south will strengthen. This will start to pull colder air into the system from the north via the opposite process – cold air advection. As a result, there is the potential for mixed precipitation to change to accumulating snowfall as the system moves past the area on Tuesday night. 

How much cold air comes into play will depend heavily on the strength of faster, confluent air flow to our north over Canada. This helps to suppress the storm south of us and pushes colder air into the area faster, leading to a more rapid change from mixed precipitation or rain to snow. 

As you can imagine, the timing and intricacies of the system will determine just how this plays out in our area. Everything is still on the table – from mostly rain to a mixed precipitation event or even mostly snow. A middle ground scenario would favor rain and mixed precipitation changing to a light accumulating snowfall on the back end of the storm. 

For now, our expectations are that we’ll see a wintry mixed precipitation event transitioning to snow at some point. When that transition occurs will determine if we see accumulating snow and how much. Interior and higher elevation areas have a better chance of seeing accumulating snow than the city.

Updates will continue from tonight into the weekend as confidence begins to increase on the intricacies of the storm. 

Have a great Friday evening!