Winter outlook for New York City
This year’s winter is expected to be starkly different from last year’s. In fact, a completely different atmospheric pattern will control our 2018-2019 winter weather pattern which favors different impacts.
It was relatively quiet in 2017 with few cold shots and near normal snowfall – until spring season snow amped up the totals in March.
Unlike last year’s La Nina weather pattern, this winter’s pattern is dominated by a weak El Nino that will favor a stronger southern jet stream – allowing more moisture to ride along the southern tier of the United States.
El Nino occurs when the sea temperatures in the equatorial Pacific undergo a warming – typically due to the slowing of the trade winds in the atmosphere directly above it. This warmer water allows more storms to convect into the atmosphere and flow along a stronger sub-tropic jet stream across the southern tier of the United States.
Weak El Nino patterns typically correspond with elevated precipitation across the Deep South. This often allows storms to enter the Atlantic and move up along the east coast as a nor’easter. Nor’easters can form in primarily two ways – one, over the Midwest, and two, from the Gulf of Mexico. El Nino weather patterns create a higher favorability for the second method of nor’easter.
Fun Fact: Nor’easters that originate from the Gulf of Mexico are called “Miller A” nor’easters in the meteorological community. Nor’easters that originate in the Midwest are called “Miller B” nor’easters.
Since El Nino is fairly weak for this upcoming season, the temperature forecast is quite challenging – thus creating an unpredictability in regard to whether it will be a warmer or cooler than normal season. El Nino patterns typically produce a warmer than normal temperatures over our area. There are other factors that point to negate or balance this effect.
For one, there is another abnormal occurrence with water temperatures in the Pacific Ocean. Not only are the equatorial waters warmer than normal (El Nino), the Pacific Northwest is experiencing a similar phenomenon.
This warmer than normal water temperature over the Pacific Northwest is called the Northern Pacific Oscillation – another irregular yet short-term climatological pattern that influences the way the atmosphere behaves.
In this particular pattern, the polar jet stream is forced farther north than usual over the Pacific Northwest. This is what we call ridging. This ridging forces cold air back toward the poles – or eastward, which in turn may favor large dips in the jet stream toward the eastern United States.
The dip in the jet stream, known as a trough, allows cold air to shoot into our local area, thus creating cold and arctic-like temperature outbreaks.
As one can see, these two patterns occurring simultaneously create a conflict.
Will it be warmer or cooler?
We can safely say that there will likely be cold outbreaks due to this northern Pacific pattern – especially with the current snowpack that is currently over Canada – which is pretty healthy.
A larger snowpack means that polar temperatures will be relatively colder due to the influences of the ice and snow. This means a stronger polar vortex. Some of that air will likely move toward us with dips in the jet stream.
So what’s the verdict?
From our analysis, we can expect to see a lot of close calls with nor’easters/coastal storms. These storms can produce a lot of snow if they come at the time of a cold air outbreak. However, if this pattern changes mid-season, this could allow El Nino’s warmer than normal temperatures to creep up the coast, too. Ultimately, we expect a big battle of temperatures over the next three months, with frequent cold/arctic shots and otherwise near normal temperatures.
We don’t see anything extreme for December aside from the temperature swings and near normal conditions.
January leans a little colder than normal since colder air is becoming more available with the situation over the Pacific Northwest and Canada.
With aforementioned higher availability of cold air and forecast shapes of the jet stream due to La Nina and the Pacific Oscillation, February this year looks snowier with a greater risk of higher impact nor’easters that can dump a lot of snow and even ice over our area.
Since we all want to know “how much snow is forecast?”…We say more than normal. Admittedly, it is nearly impossible to forecast exact amounts, but we can take a guess to say, "here’s what we’re thinking…"
Overall, the snow forecast is calling for slightly above normal to well above normal snowfall.
Always Be Prepared…
It doesn’t matter whether it will be an intense or weak winter, it is always important to be prepared to face all kinds of winter weather. It shouldn’t matter if its 2 inches or 2 feet – plan to have a full tank of gas, a shovel, ice scraper, and an emergency kit in your car. Winterizing your car can save your life if caught in an unpredictable and hazardous situation.
Nor’easters can be challenging to forecast, so always plan with safety in mind with every storm that comes our way. News 12 will always keep you informed with the latest developments and changes to a storm on our weather page.
Click here for the News 12 Weather Center.