For the upcoming 2023-2024 winter season, a moderate to strong El Niño is expected.

In this article, we will review what El Niño is, its historical impact on winter weather in Japan, and review the Japan Meteorological Agency’s 2023-2024 winter forecast. 

Before we get into the details, it's important to remember that long-range forecasts are challenging and the skill level is low. While these forecasts can give you an idea of what may happen during the season, OpenSnow All-Access has all the tools to help you maximize your weekend trip or destination ski vacation.

What is El Niño?

To recap, El Niño means that water temperatures in the Tropical Pacific Ocean are warmer than average, and this change in water temperatures can change weather patterns around the world. 

As sea-surface temperatures in the equatorial Pacific warm and cool, the atmospheric circulation undergoes changes that bring various impacts during Winter. Below is the typical SST pattern for El Nino.

(Image courtesy of NOAA)

As the circulation of the air above the tropical Pacific Ocean responds to the redistribution of heat due to the warmer waters, the balance of atmospheric pressure across the entire region is altered.

(Image courtesy of NOAA)

(Above: Air circulation patterns over the tropical Pacific Ocean during neutral and El Nino conditions. The regions of rising and sinking motion shift during El Nino. The orange in the lower figure shows warmer than normal SSTs)

As a result, the wind and rainfall patterns in this region have changed. Ultimately, these patterns over the tropical Pacific are transmitted to regions away from the tropics via disruptions to the jet stream. 

The typical global Winter El Niño impacts are shown below. During El Niño years, above-normal temperatures are common across the southern part of Japan. This region is typically wetter than normal during El Niño years as well. 

(Image courtesy of the JMA)

JMA 2023-2024 Winter Forecast

Overall, the JMA winter forecasts predict above-normal temperatures, most likely in the southern half of the country, a slight chance for above-normal snowfall on the Japan Sea side of the southern half of the country, and a slight chance for below-normal snowfall on the Japan Sea side of the northern part of the country (Hokkaido).

However, the percentages in these products can be a bit tricky to make sense of. It is important to understand that these are probabilistic outlooks that only tell us which way the odds tilt.

JMA 2023-2024 Winter Temperature Forecast

(Image courtesy of the JMA)

The odds are tilted toward above-normal temperatures in the south, with a slight tilt towards above-normal temperatures in the northern half of the country as well.

The JMA is predicting above-normal temperatures for all of Japan, with the best chance in the southern half of the country (60% probability). This also contains a 30% chance for near-normal temperatures and a 10% chance of below-normal temperatures. In the northern part of the country, the JMA predicts a 40% chance for above-normal temperatures, with a 40% chance for near-normal temperatures and a 20 percent chance for below-normal temperatures. 

JMA 2023-2024 Winter Precipitation Forecast

(Image courtesy of the JMA)

The odds are slightly tilted toward above-normal precipitation in the southern part of the country, and a slight tilt towards above-below-normal precipitation in the north. 

Most of the southern half of Japan falls in the 40% chance for above-normal precipitation category. This means that there's a 40% chance for above-normal precipitation, a 40% chance for near-normal precipitation, and a 20% chance for below-normal precipitation. 

For the Japan Sea side of the northern half of the country, the JMA predicts a 40% chance of below-normal precipitation, with a 30% chance for near-normal or above-normal precipitation. Meanwhile, on the eastern side of the northern half of the country, the JMA is predicting a 40% chance of near-normal precipitation, with a 30% chance for above or below normal.

Overall, the JMA doesn’t believe there are strong indicators of either below or above-normal precipitation for most of the country, but if one scenario is more likely to happen, it would be below-normal precipitation in the southern half and above-normal precipitation in the northern half of the country.

JMA 2023-2024 Winter Snow Forecast

(Image courtesy of the JMA)

Finally, let’s take a look at the snowfall forecast from the JMA. Despite the slight chance for above-normal precipitation in much of southern Japan, the odds are somewhat tilted toward below-normal snowfall in the western part of the country including the southern half. The JMA has a 50% probability for below-normal snowfall along the Japan Sea side of the southern half of the country, with a 30% chance of near normal and a 20% chance of above-normal snowfall. Farther north along the coast, the chances for below-normal and near-normal snowfall are 40%, with a 20% chance of above-normal snowfall.

Finally, along the west coast of Hokkaido, the probability for below-normal snow is slightly less, with a 40% below-normal snowfall, and a 30% chance for both near-normal or above-normal snowfall. 

Overall, the northern island of Hokkaido has the best odds for a cool and snowy winter. 

Keep in mind that one or more of these climate patterns have occurred during many El Niño events in the past, but that doesn’t mean that all of these impacts happen during every El Niño.

Final Thoughts

If you want to give yourself the best chance for powder, book a trip 7-10 days in advance for a general area that looks stormy. 

If you're ready to level up your weather app for the upcoming winter season, consider upgrading to OpenSnow All-Access. Whether you’re chasing powder, searching for sunny days, or something in between, our 10-day snow forecasts, expert "Daily Snow" forecasters, and high-resolution weather maps have you covered.

But don't just take my word for it ... "Any weather app can give a mediocre forecast for a mountain town, but only OpenSnow provides a good idea of actual mountain conditions. It's a small price to pay ($29.99/year) for the best weather forecasts." – Real App Review

Download the free OpenSnow app for the most accurate snow forecast and snow report information and stay tuned to our weather forecasts for the latest updates.

Luke Stone
Forecaster, OpenSnow