Much colder air on the way to NYC next week
A large ridge in Alaska and the development of a cross-polar flow will deliver the coldest air of the season (so far) to NYC next week.
For the last several weeks, NYC has been fortunate enough to enjoy a relatively warm weather pattern. Temperatures have averaged several degrees warmer than normal, leading to an unusual amount of pleasant weather days in both October and November. The fun ends this week.
The culprit is currently situated a cool 4,500 miles to our northwest. A large ridge of high pressure developing over Alaska is forecast to dislodge arctic air southward into the United States in the next few days.
The ridge is impressive in its own right, with forecast model guidance suggesting that atmospheric heights at 500hPa will reach 4 standard deviations higher than normal. This anomalous event is one of the main reasons why we’re so confident in the development of cold.
When anomalous ridging develops in this region, cold air which normally resides in the Arctic is dislodged southward. A cross-polar flow of air flows directly into Canada and the United States, leading to temperatures averaging several degrees below normal.
Forecast model guidance is in good agreement that this pattern will last a while. All ensembles agree that the temperature in NYC will average colder than normal for the next several days – at the very least into next weekend. High temperatures will likely average from the low to mid 40’s in the city and a bit cooler in the suburbs.
Some of the coldest air may arrive this weekend, when guidance suggests an arctic front will swing southward into the Central United States. While it’s a bit early for snow especially in the NYC Metro, colder than normal air is surrounding the area. Some form of winter weather is not out of the question, though there are no particular threats on the horizon yet.
For now, get ready to settle in to a colder than normal pattern. It’ll surely be a shock to the system after several weeks of warmth. Buckle up!