Dramatic Temperature Swing brings NYC Another Bout of Winter

With unseasonably warm temperatures causing trees and flowers to bloom early across New York City, it has felt like spring here for more than a few weeks. But now, as April begins, winter has come fighting back for an encore performance.

The high temperature in Central Park on Friday was a balmy 79°F.  Today, it was only 45°F and even colder conditions are expected as the week goes on. So, what’s causing this dramatic cool down? The answer lies in the changeable pattern of the jet stream.

A persistent area of high pressure had been sitting off the eastern seaboard recently, creating a ridge in the jet stream and blocking any cold air from moving southward. Now, the pattern has shifted and a trough in the jet stream is allowing cold air to spill out of Canada and across the northeast.

The first wave of chilly air moved through on Sunday and caused powerful winds to whip through the area. The NWS reported winds gusts of 45 mph in Central Park and 64 mph at JFK airport.

Another wave of arctic air is expected tonight. With the temperature projected to plummet into the 20’s, the NWS has issued a freeze warning for the city and surrounding area – bad news for all the early blooming plants and trees. The forecast high for Tuesday is only 39°F. The city’s normal high for this time of year is 57°F and the normal low is 41°F.

As spring is a transitional season, temperature swings between warm and cold are not uncommon. But, after the city’s second warmest winter and fourth warmest March on record, many folks are finding this spring cold snap more than bit jarring.

NYC Monthly Summary: March 2016

March 2016 was more like a lamb than a lion in New York City this year. With an average temperature of 48.9°F in Central Park, which is a staggering 6.4°F above average, it was the city’s 4th warmest March on record.

Overall, we had 23 out of 31 days with above average temperatures. Five of those days posted readings in the 70s and two set new daily high temperature records. Historically, our average temperature for the month is 42.5°F.

While a few warm days in March is not that uncommon, this extended pattern of sustained warmth was unusual. Driven primarily by El Niño, a persistent ridge in the jet stream over the eastern US allowed warm southern air to flow further north than it normally would at this time of year.

Given this unseasonable warmth, it is not surprising that only 0.9 inches of snow was measured in Central Park this March. On average, NYC usually receives 3.90 inches of snow for the month.  Rainfall was also scarce.  In all, the city received a mere 1.17 inches of rain. That is 3.19 inches below normal.

March_Temps

23 out of 31 days posted above average temperatures this March in NYC. Credit: The Weather Gamut