NYC Winter Forecast 2022-2023: Colder start, active and warmer finish
Highlights: The Winter of 2022-2023 is likely to begin with a somewhat cool, wintry pattern during the months of December and January. The second half of the winter will trend more volatile and could end warmer than normal in February. NYC’s 30 year average annual snowfall is 28.9″, and we expect slightly above normal snowfall this season.
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We say it every year, but it is worth repeating: Seasonal weather forecasting is one of the most challenging aspects of meteorology. It is the product of several months of intensive research, which often begins in the prior Spring. We have been piecing together ideas for this upcoming winter since then, and we are excited to finally have a finished product to share with you.
Within this forecast, we are going to try to paint a picture of the atmosphere and what it’ll be doing over the next few months based on several global and hemispheric oscillations, conditions, and phenomena. This will lead us to conclusions which we believe will be the guiding forces for us during the seasons ahead.
This forecast will be a bit more complex than our usual posts. Stick with it – we’ll do our best to explain what everything means and we have several videos coming in the next few days to break it all down, too.
The role of ENSO
Anticipated ENSO Conditions: Weakening La Niña
The El Niño-Southern Oscillation (ENSO) is an irregular periodic variation in winds and sea surface temperatures over the tropical eastern Pacific Ocean. ENSO conditions are one of they key drivers to the Winter pattern, and can often be broadly referenced as “tropical forcing”.
Tropical forcing more specifically refers to concentrated areas of showers and thunderstorms, otherwise referred to as convection, in meteorological regions of the tropics. This convection, most frequently observed in warm and moist climates, releases latent heat that then rises up into the atmosphere, forming ridges of higher atmospheric air pressure.
The equatorial waters of the Pacific Ocean that comprise the ENSO regions breed a great deal of thunderstorm activity, which then accordingly results in atmospheric ridging and subsequently moves downstream. This balances the atmospheric regime. In a general sense, the more anomalous the positive sea surface temperatures, the more convection that can then exert a stronger forcing mechanism on the adjacent regions of the atmosphere, reverberating throughout the globe.
Almost all forecast model guidance now agrees that we will experience weak La Nina conditions during the upcoming winter, but see weakening impacts from the La Niña overall as the winter goes on. La Nina conditions are observed when colder than normal temperature anomalies exist in the aforementioned tropical regions of the Pacific Ocean.
SSTA Analysis (Sea Surface Temperature Anomaly)
The ongoing La Nina event is expected to continue to remain in control through the first few months of the winter. Thereafter, weakening effects of the La Nina are gradually anticipated as we move through the winter months. Meanwhile, widespread warmer than normal sea surface temperatures exist in the North Pacific as well as the North Atlantic and Arctic. The combination of these factors leads to increasing confidence in a volatile pattern by mid to late winter with the possibility of high-latitude blocking episodes.
Using a weighted analog set with years featuring similar conditions from the past, we are able to compile an analog set of the SST anomalies in the Tropical Pacific. This analog set matches quite closely with ongoing and expected conditions.
This analog set is important. It helps us to understand where we are heading during the winter ahead and how global circulation patterns may behave. Having confidence in the orientation of SST anomalies in the Tropical Pacific is a key part of the winter forecast and serves as a foundational piece of the forecast as a whole.
The Quasi-Biennial Oscillation (QBO)
Prediction: Westerly QBO
The Quasi-Biennial Oscillation, or QBO, is a measure of zonal winds in the stratosphere (the level above the troposphere, where we experience most of our weather) that typically oscillate between westerly (positive) and easterly (negative) phases, every 12-24 months. The QBO in an easterly phase tends to promote a weaker polar vortex in the stratosphere, resulting in a propensity for more stratospheric warming events during the winter months (allowing high latitude blocking and -NAO episodes to flourish). The QBO in a westerly phase tends to allow a stronger polar vortex to form, limiting high latitude blocking and resulting in a more positive AO and NAO phase during the winter months.
The QBO is currently in a westerly phase, suggesting the possibility of some resistance to high latitude blocking events.
The North Atlantic Oscillation (NAO)
Prediction: Neutral to Negative (-) NAO on average, especially early in the winter
The North Atlantic Oscillation (NAO) is an index based on the surface sea-level pressure difference between the Subtropical (Azores) High and the Subpolar Low. The positive phase of the NAO reflects below-normal heights and pressure across the high latitudes of the North Atlantic and above-normal heights and pressure over the central North Atlantic, the eastern United States and western Europe. The negative phase reflects an opposite pattern of height and pressure anomalies over these regions.
A -NAO has historically been correlated to stormy and cooler weather in the Northeast United States and the NYC Metro region, especially during the winter months.
Despite the westerly QBO, European seasonal data has strongly indicated the presence of a -NAO during the months of November, December and January during several recent updates to its seasonal model data. This fits generally into the regime apparent on many of our SST and global pattern analogs.
A -NAO during the months of DJF would ensure an active and likely cooler than normal pattern across parts of North America.
Analog Analysis & Other Factors
The importance of analogs in a Winter Forecast has been long debated and discussed. How much should a forecaster weigh what happened in the past against what is happening currently? How can we utilize past events when the atmosphere is almost certain to behave differently each time, especially given the difference in global weather when compared with weather events from the 1950’s and 1960’s?
For us, each winter is different. This year in particular, the number of analog years that fit the set of conditions and the overall progression of the atmosphere is very slim. There are simply very few years that featured a third year La Niña, expected to weaken with similar stratospheric and tropospheric evolutions across the globe.
With that in mind, we decided to weight the analog years in our forecast very carefully, taking only the stronger year(s) and blending quickly downward toward the weaker analogs. We’re comfortable with our analog composites that were presented and have factored them into our forecast as we typically do. Think of them as a piece of a much larger forecast puzzle.
When we take the individual pieces of research and compile them into one organized forecast, we can begin to see the ebbs and flows of the winter ahead, as they should be, according to our very best analogs and subset of current and past conditions. This winter, we are confident in our month-to-month composites and have indicated moderate to high confidence on each month.
Below, we break down each month’s temperature and anticipated precipitation trends. While precipitation maps aren’t included (lower confidence), we do discuss precipitation patterns and potential within each individual month’s breakdown. Please keep in mind that this forecast is focused on NYC, but national trends are discussed as well.
December 2022
One of the more complex December forecasts in the last decade, our current forecast calls for a colder than normal pattern across the Northern Plains and Great Lakes with the possibility of substantially colder than normal conditions in the Dakotas, Minnesota and the Upper Midwest at times. Meanwhile, warmer than normal temperatures are expected from the Desert Southwest into the Southern Plains and Southeast States. An active storm track is forecast from the MS Valley into the Ohio Valley and Northeast states.
January 2023
The forecast for January features a volatile and cooler than normal pattern across the Great Lakes, Upper Midwest, Ohio Valley and Interior Northeast states as high latitude blocking continues to control the pattern across the Northern Hemisphere. Ridging is forecast to develop and expand in parts of the Four Corners and Western US which will also aid in pattern amplitude across the East. Overall, an active and volatile month is anticipated.
February 2023
The forecast in February is highly uncertain and will depend greatly on the evolution of ENSO conditions across the Tropical Pacific during the winter months. This is an exceptionally low-confidence forecast, even compared to usual. Still, the expectation is that warmer than normal temperatures will begin to expand again in the Southern Plains including the Southeast States with the return of some Southeast US ridging. Cold risks are highly uncertain at this time especially their placement, breadth and intensity and limited colder than normal regions were included in the map as a result.
NYC Forecast Review & Summary (December, January and February)
A near-normal temperature profile is expected this winter in NYC, with colder risks early and warmer risks later in the winter. Precipitation is forecast to average above normal for the winter months. Snowfall is expected to average slightly above normal.
It’s worth nothing that the current expectations are for a more wintry start than usual – but that’s not saying all that much. The last several Decembers have been quite warm and not very active in terms of snowfall in NYC. This December and January could be quite different.
Finally, I wanted to take the time to say thank you to everyone who continues to support us and read our content. It is not lost on me just how special it is that so many people take the time to read what we have to say. This is our tenth (!) year putting out a winter forecast. Thank you for being there.
