La Niña and comets

A new La Niña has arrived, according to forecasters at the Climate Prediction Center. Sea-surface temperatures near the West Coast of South America and along the equatorial regions are now cooler than normal as La Niña conditions were indicated beginning last month. Based on the current predictions, this new La Niña is expected to persist at least through February 2026.

As ocean waters cool in the south-central Pacific Ocean, this may have an impact on the end of the Atlantic and Caribbean tropical storm and hurricane season. The season officially ends Nov. 30, and it has already passed the peak of the season, which was around Sept. 10. However, activity may start to increase once again later this month and into early November.

The average number of named storms is 14. Out of those named storms, there are an average of seven hurricanes, with three of them becoming major. As of the weekend, there have been 11 named storms and four hurricanes. The damage from these storms has been approximately $110 million.

This is a very different scenario when compared to last year. For the 2024 season, there were 18 named storms with 11 hurricanes. There were also six major hurricanes that were Category 3 or higher. The total damage in 2025 was a whopping $130.4 billion, which was the third costliest season in recorded history.

Despite the onset of a new, cooler La Niña event, ocean waters across the rest of the globe are near to above normal levels. The chart shows that the warmest regions are from eastern Asia to much of the U.S. West Coast. Some ocean regions near the equatorial regions in the North Pacific are over 4 degrees above average. It’s difficult to say at this time, but the warmer waters near the West Coast could bring in warmer air into the northern U.S. and lead to more rain than snow this winter season.

During La Niña events, moisture totals will often increase across the northern U.S., especially here in North Idaho. Despite the warmer waters in the eastern Pacific Ocean, we still have a better chance of higher snowfalls during the winter season. Some of the forecasts are predicting above-average snowfalls across the inland portions of the Pacific Northwest, the Great Lakes region and across parts of the southern Midwest.

By contrast, below normal snowfalls are forecast across the mountains in the southwestern U.S. This may also include California’s Sierra Nevada mountains. Cliff and I will have our detailed city and town snowfall outlooks for North Idaho and eastern Washington next week.

This new La Niña may already be having an influence on the weather in California. Rainfall has been increasing across the northern portions of the Golden State this month. In fact, Sacramento has reported more moisture than Coeur d’Alene through the first 11 days of the month.

However, with the new La Niña, conditions are starting to change. Much-needed rainfall was reported over the weekend, with snow in the mountains across the region. As of this writing, there was even the chance of some snow in the lower elevations early in the week.

According to the long-range computer models, after the wet weather in the early part of the week, the next chance of shower activity is at the end of this week. It looks like we’ll have a better chance of additional moisture toward the end of the month. There’s also the possibility we may see some snow during that time, but as always, it’s a temperature thing in this part of the country. Stay tuned.

On another note, stargazers may be able to view two comets that were recently discovered. Comets are made of ice, rock and frozen gases. As they travel near the sun, the heat will cause them to release the gas that creates their tail.

Comet SWAN and Lemmon are making their appearance this month, and they have their closest approach to Earth on Oct. 20 and 21. The best way to view them will be with binoculars or telescopes and away from city lights. Scientists say that both comets can be observed in the early evening shortly after sunset when conditions become dark. Comet SWAN is expected to be within 24 million miles of Earth on Oct. 20, and Lemmon will be within 55 million miles Oct. 21. And in case you miss these two comets, there are more comets expected to pass by our planet late this year and into early 2026.

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Contact Randy Mann at [email protected].