El Niño has arrived and will begin making impacts on weather around North America starting this summer. We highlighted the summer impacts in an article published last week that you can view here. While El Niño will impact the weather this summer, the El Niño–Southern Oscillation (ENSO) is notorious for affecting winter weather in North America. 

Typically, El Niño brings warmer temperatures and drier conditions to much of the Western United States because the Polar jet stream shifts north. As the Polar jet stream shifts north, the Subtropical jet stream can move into California and the Southwest. This brings atmospheric rivers, which create wetter than normal conditions and more snow for the higher terrain. 

Storms or atmospheric rivers that affect California and the Southwest move across the Southern US and can strengthen into Nor’easters, bringing snow to the East Coast. Additionally, the Polar jet stream can swing through the Great Lakes and cause cold air outbreaks. This can bring lake effect snow to the Upper Midwest and Northeast. 

How do we know El Niño will last through next winter?

El Niño patterns typically last 9-12 months so if we do the math from May 2023, that takes us into at least February 2024 (9 months). This is determined from a statistical measure since NOAA has been keeping track of ENSO patterns since 1950. Additionally, numerical models are used to predict ocean temperatures and weather patterns several months and even a year or more in advance. 

Some of the latest numerical model guidance from NOAA shows the probability of El Niño for next winter at a considerable amount (over 80%).

Graph showing Percent Chance (%) of El Niño for several three-month periods. (i.e., DJF - December, January, February). Image courtesy of NOAA. 

The graph above shows how likely El Niño will occur throughout the next year and into 2024. This is only for the minimum criteria of El Niño, which is ocean temperatures above (0.5 degrees C). Right now, the ocean temperatures around the Equator are 0.9 degrees C above normal. NOAA has forecasted El Niño to strengthen and has an 84% chance of ocean temperatures reaching above 1.0 degrees C next winter (moderate El Niño).

Graph showing several numerical models forecast of ENSO ocean temperatures anomaly for different three-month periods. (i.e., DJF - December, January, February). The average forecast is the green line (+1.5 degrees C). Image courtesy of NOAA. 

How will El Niño impact winter weather?

The impact of El Niño has different effects on weather around North America. The first image in this article highlights the typical winter weather patterns across North America. It is important to note that this is a “typical” pattern and is based on the statistical dataset since 1950. 

There are several recent winters that we can look at to see what this year's El Niño will bring (1991-92, 1994-95, 1997-98, 2002-03, 2004-05, 2009-10, 2014-15, 2015-16, and 2018-19). The following maps show the precipitation anomalies (top) and temperature anomalies (bottom) for these El Niño winters averaged out. 

These winters gave above average precipitation to California, the Southwest, and areas along the East Coast, as well as slightly below average temperatures to some areas in the Southwest and East Coast.

Will these conditions prevail for the 2023-24 winter?

The analog years highlighted above give some indication of what this next winter might be like. It is important to note though, that there can and will be exceptions to the “typical” El Niño winter weather pattern. Each El Niño event is different and unique.

This past winter (2022-23) was a notable exception to what ENSO, in this case La Niña usually brings. For example, California typically sees more snow during El Niño but this La Niña brought record-breaking snow to California as well as other areas in the West.

While we can look into past statistics to help infer what might happen next winter (from a large-scale perspective), the key to knowing when and where to find powder requires us to focus on forecasts made 1-10 days in advance.

Let’s hope for another good winter throughout North America, much like the El Niño of 2015-16 brought to many areas across the West. The OpenSnow team certainly took advantage of it.

We will continue to monitor the emerging El Niño as the summer progresses, and stay tuned later this summer for more deep dives into winter outlooks for 2023-2024. 

Also, be sure to use our Forecast Anywhere feature to view custom point forecasts for any location and elevation in the world as you plan your summer outdoor adventures.

Zach Butler