Winter outlook for New York CityPosted: Updated:
- The 2017-2018 winter season is driven by a persistent, yet weak, La Nina pattern which favors an overall slightly warmer-than-normal overall season with near normal snowfall.
- ‘Clippers’ will be the primary sources for cold air and any snowfall. These storms originate from the Canadian provinces of British Columbia, Alberta, Manitoba, Saskatchewan, and sometimes western Ontario. They are commonly called “Alberta Clippers”, but storms that form in Manitoba are less commonly known as “Manitoba Maulers”, and Saskatchewan storms are referred to “Saskatchewan Screamers”. For our purposes, we will just call them ‘clipper systems’.
- Coastal storms will not be as frequent as clipper systems. For any coastal storms, we could expect more rainy and icy scenarios than blockbuster snow. Although blockbuster snow cannot be fully ruled out, the chances are in favor for the rainy and icy scenarios for the city. Areas north and west that traditionally see snow when we see rain would likely still see some snow impacts by coastal systems. Every year we usually see an intimidating coastal storm move along the coast, and we will probably see a similar scenario this year, but on occasion and not often.
- La Nina will be responsible for large temperature swings through the season, despite an overall warmer-than-normal trend. Cold blasts (or dips in the jet stream) will arrive frequently, and they can arrive with clouds and showers. Depending on the bitterness these cold shots, snow showers and squalls are possible, but would be short-lived only lasting 6-12 hours. With the cold lasting for a day or two after the initial blast, the air between these cold shots would then begin to moderate to warmer than normal.
Justification for bitterly cold can be related to, in part, to the current snowpack that
exists across the Canadian frontier. At this time last year, there was no snowpack, but
this year features an already healthy snowpack existing across the majority of the
provinces. Air above the snowpack will typically trend cooler by several degrees, thus
moderating a colder air mass above the Canadian provinces. Combine this with a La
Nina, the jet stream will be in favor of sending this cold air toward the Midwest and
northeast. This year will be good for skiers/snowboarders along the northeast slopes.
Chart of Normal DJF temps
- Regarding snowfall: This season is forecast to be near normal or slightly above given the limited chances for coastal storms, increased warmth, and enhanced clipper-system frequency.
Snowfall Forecast DJF