Could we see a strong El Nino this year?

We currently have a weak, cooler than average sea-surface temperature event, La Nina, in the waters of the south-central Pacific Ocean. According to the U.S. Climate Prediction Center, the La Nina is expected to weaken in April to a neutral, or La Nada, which is the in-between cooler La Nina and warmer El Nino. Forecasters are also saying that a new El Nino is likely to form during the summer season and continue through the end of the year. There is also a good chance that this new El Nino could be very strong at the end of 2026. While La Ninas and El Ninos usually span across two calendar years, it is not uncommon for one phase to end and the other to begin within the same 12-month period.

A strong El Niño occurs when unusually warm ocean temperatures develop in the central and eastern Pacific Ocean, altering atmospheric circulation and weather patterns across the globe. In the United States, these changes are especially noticeable during the winter months and can bring both benefits and hazards depending on the region.

One of the most consistent impacts of a strong El Niño in the U.S. is a shift in the upper-level jet stream. The subtropical jet stream tends to strengthen and move northward, bringing increased storm activity across the southern tier of the country, including California, Texas, and regions along the Gulf Coast. This can be beneficial in drought-stricken areas, particularly in California, where increased rainfall and snowfall in the Sierra Nevada help replenish reservoirs and snowpack. However, excessive precipitation can also lead to flooding, landslides, and infrastructure damage, especially when storms are intense or prolonged.

By contrast, the northern United States, including the Pacific Northwest, northern Plains, and parts of the Midwest, typically experiences warmer and drier conditions during a strong El Niño as the northern polar jet stream, the one that has a high influence on our weather, will often weaken and move northward. The winter seasons in these regions are often milder than usual with reduced snowfall.

A strong El Niño will also tend to suppress Atlantic hurricane activity due to increased wind shear over the Atlantic Ocean but enhance storminess in the Pacific Ocean. As a result, the southern U.S. may see an increased risk of severe weather events, including thunderstorms and tornadoes. With the El Nino expected to form late in the year, the 2026 tropical storm and hurricane season is forecast, at least at this time, to have close to the normal 14 named storms. I’ll have more updates on this forecast in the coming weeks.

The most intense El Nino events in recent history occurred in 1982-83, 1997-98 and 2015-16. During these years, the effects along the west coast of South America, particularly in Peru and Ecuador, were disastrous as warm ocean waters suppressed the usual upwelling of vital nutrients. This resulted in the devastation of area fisheries and caused massive declines in anchovy populations. At the same time, these regions also experienced intense rainfall that led to severe flooding, landslides, and infrastructure damage.

In other parts of the world, countries like Australia and Indonesia suffered extreme drought conditions. These dry conditions contributed to crop failures, water shortages, and widespread wildfires. In India, the monsoon weakened, reducing agricultural productivity and affecting food supply.

The United States also experienced unusual weather from the strong El Nino events. The southern states often experienced heavy rainfall and flooding, while parts of the northern regions had milder winters than usual.

The event in 1997-98 was one of the strongest El Ninos ever recorded in the 20th Century. During that time, precipitation totals for 1997 and 1998 were slightly above average across the Inland Northwest.

However, the El Nino event in 2015-16 is widely considered to be the strongest ever observed, just surpassing the big 1997-98 El Nino. It had the highest sea-surface temperature anomaly with readings higher than normal by approximately 5 degrees Fahrenheit. During the 2015-16 season, snowfall was below normal and rain and melted snow was a little higher than normal in Coeur d’Alene and surrounding regions. At Cliff Harris’s station for the 2015-16 snowfall season, a total of 56.2 inches of snow was measured with 34.2 inches at the Spokane International Airport. However, once the big El Nino weakened, snowfall dramatically increased across the region in late 2016. In fact, the 2016-17 season had over 115 inches of snow in parts of Coeur d’Alene.

In terms of our local weather, more moisture is expected across the Inland Northwest this week. Most of what falls is expected to be in the form of rain in the lower elevations, but there is still the chance of some snow during the overnight and early morning hours. After this week, the odds of any measurable snow in the lowlands are extremely low.

The latest spring forecast from NOAA calls for a drier than normal weather pattern across the Inland Northwest. The upcoming summer season also looks to be drier than average as well with temperatures near seasonal averages. Stay tuned.

• • • 

Contact Randy Mann at [email protected].