Unveiling which regions may experience heavier snowfall this winter with the influence of a powerful El Niño

The National Oceanic and Atmospheric Administration (NOAA) has released maps predicting snow accumulation in the United States as the country prepares for a winter heavily influenced by a powerful El Niño event. This El Niño is projected to be the strongest since the 2015-2016 one, which resulted in the warmest winter on record across the contiguous US.

The pattern of El Niño winters typically brings wetter and cooler weather to the southern US, while the north experiences drier and warmer conditions. This is what is forecasted for this winter. However, it's important to note that increased rainfall does not always equate to more snow. Additionally, the amounts of snowfall can vary significantly from one location to another.

The new maps provide insight into the likelihood of snowfall during El Niño winters in comparison to average conditions. However, it is important to note that these maps serve as historical guides rather than accurate forecasts. A complete snowfall forecast would consider numerous atmospheric and climatological factors beyond just El Niño.

During all El Niño winters (January-March), snowfall is compared to the 1991-2020 average by removing the long-term trend. The color blue signifies above-average snowfall, while brown represents below-average snowfall.

The map above illustrates the deviation of snowfall from the average during all El Niño winters, irrespective of the intensity of El Niño. The dry trend, which is usually observed in the northern United States, is clearly indicated by the tan and brown shading, while the wetter and snowier trend in the southern United States is depicted by the blue shading.

This occurrence is a result of the southward shift of the jet stream, which directs storms towards the southern regions of the country, while reducing their occurrence in the north. Consequently, an increase in winter storms leads to a higher probability of snowfall.

The impact of an El Niño becomes more amplified as it grows stronger. The map below illustrates the data for winters with stronger El Niño events. The darker hues on the map indicate more extreme shifts in snowfall compared to an average El Niño event.

Snowfall during all stronger El Niño winters (January-March) compared to the average from 1991 to 2020 (after accounting for the long-term trend). The blue color represents above-average snowfall, while the brown color represents below-average snowfall.

NOAA Climate.gov

The regions that have emerged as the major beneficiaries of heavy snowfall include the mid-Atlantic, high elevations of the Southwest and California, and the southern states, with one crucial condition. In areas such as Texas and the Southeast, where temperatures often remain relatively warm, the likelihood of snow is lessened, as cold conditions are necessary for snowfall.

On December 28, 2022, in Buffalo, New York, an excavator (C, bottom) can be seen in this aerial photograph making its way up Richmond Avenue. The devastating winter storm that struck the US during the Christmas weekend wreaked havoc on New York state, leaving air travelers and residents alike grappling with its aftermath. Dubbed the "blizzard of the century," tragic stories emerged of families trapped for days, adding to the mounting death toll that exceeded 50. As the epicenter of the crisis, Erie County in western New York experienced three more confirmed fatalities, further highlighting the severity of the situation.

Joed Viera/AFP/Getty Images

A classic El Niño winter is expected this year, forecasters say. Heres what that means for snow and cold

The impact of El Niño on the jet stream is most evident in the western regions with elevated terrains, where cold weather and snowfall are typically abundant. The mountains in the Southwest and California flourish thanks to increased storm activity, while the Northwest experiences a decrease in precipitation due to fewer storms.

When it comes to snowfall prospects in the mid-Atlantic region, storms tend to follow a path along the Appalachian Mountains or veer towards the coast and transform into nor'easters.

During El Niño, these nor'easters can become more intense with the addition of abundant tropical moisture, resulting in an average of "two to three significant snowstorms," as stated by Jon Gottschalck, the chief of the Operational Prediction Branch of NOAAs Climate Prediction Center. As a result, cities like Washington, DC, and Baltimore, which experienced less than an inch of snow last winter, could potentially receive above-average snowfall.

Despite the Northeast typically experiencing less snow during a powerful El Niño winter, the entire season's snowfall can be significantly affected by a single massive storm, such as an intensified nor'easter.

Snow enthusiasts in the Northwest and Midwest must also join their counterparts in the Northeast and wish for a substantial storm, as stronger El Niños have historically resulted in below-average snow accumulation.

The chart depicts the occurrences of below-average snowfall during the January-March period in the 13 moderate-to-strong El Niño winters since 1959. Red indicates locations where more than half of the years experienced below-average snowfall, while gray represents areas where below-average snowfall occurred in less than half of the years studied.

NOAA Climate.gov

Removing snowfall totals from the map and focusing on the number of stronger El Niños with below-average snowfall helps suss out outlier storms.

The map above displays darker red areas, indicating regions that have had below-average snowfall for more years during moderate-to-strong El Niño winters. The typically snowy Midwest and Northeast regions, which already face snowfall deficits, prominently stand out, suggesting that these areas are often most affected by El Niño, resulting in significant snow loss.