La Niña is strengthening in the Pacific waters

It’s been one of the warmest and driest starts to October in recorded history across the Inland Northwest. There were four days in a row with high temperatures at or above 80 degrees at Cliff’s station in northwestern Coeur d’Alene. We came close to tying a record last week as the high was 80 degrees on Oct. 5, only two degrees below the record for the date. The warmest afternoon was on Oct. 4, with a high of 81 degrees. At the Spokane International Airport, there were only two days this month with highs in the 80s.

For the first week of October, our average high temperature in Coeur d’Alene has been 79 degrees, which is 13 degrees above-normal. The normal high temperature in the middle of October is about 60 degrees. It’s now looking like we’re going to see at least a few days with readings in the 70s during that time.

After a long stretch of mostly dry weather this summer, 0.99 inches of rain fell in Coeur d’Alene on Sept. 29, which was a record for the date. For the summer season from June 21 through Sept. 22, Coeur d’Alene had only 1.09 inches of rain. With the additional 0.05 inches received the next day taking the storm total to 1.04 inches, we picked up almost the entire total of our summer rainfall within 24 hours. Since that date, it has turned very dry and warm with very little rainfall expected until at least the end of the month.

It was looking like we were going to see some light-to-moderate rain in the middle of October during the full moon lunar phase, but the ridge of high pressure is very strong and taking its time to break down. At the end of this month, we’ll be in the new moon lunar phase, which is often wetter and cooler.

During this period of extreme weather, the dry and warm pattern we’re seeing now will eventually flip to the colder and wetter side. With an expanding La Niña sea-surface temperature pattern in the waters of the south-central Pacific Ocean, we should start to see an increase in moisture either late this month or in November. Cliff and I are already seeing conditions in the Sea of Japan and the Gulf of Alaska becoming more active. Eventually, these active weather patterns will migrate into the Northwestern U.S. giving us a good chance of moisture.

Speaking of La Niña, over the last month, La Niña has been strengthening to the point where Australian forecasters have declared a third La Niña event in a row. Ocean temperatures in some locations along the Equator are about 2-4 degrees below average. The latest forecasts are calling for La Niña to peak over the next month or two, then we’ll return to “La Nada” conditions, the in-between La Niña and warmer El Niño, early next year. There are a few computer models that track sea-surface temperatures, and they are pointing to a slight chance of a warmer El Niño toward the end of 2023.

While ocean temperatures are still cooler-than-normal along the Equatorial regions, they are still warming north of Hawaii. The warmer waters also extend to the Gulf of Alaska and along the West Coast. The warmer-than-average sea-surface temperatures in the eastern Pacific Ocean could also play a part in determining how much snow we receive in North Idaho this upcoming winter. Right now, Cliff and I are forecasting for our region to experience slightly higher-than-average snowfall totals.

We’re also seeing moderate to extreme drought conditions, mainly west of Interstate 35 in the center of the U.S. Extreme to exceptional drought conditions are being reported in parts of Nebraska, southern Kansas, and much of Oklahoma and central Texas. There has also been some expansion of severe drought into northwestern Iowa. The western regions that include California, Oregon, Nevada and Utah are also experiencing severe to exceptional drought.

Here in the Northwest, most of northern Idaho is under the category of “abnormally dry,” according to the U.S. Drought Monitor. However, there is a “moderate drought” in eastern Washington and most of central and southern Idaho. The extreme southern portion of our state is experiencing “severe drought” conditions. The latest data does show that close to 70% of the U.S., including Hawaii, is currently experiencing conditions from abnormally dry to exceptional drought. The only portion of the country that has good moisture levels overall is east of the Mississippi River.

As far as the tropical storm and hurricane season, there have been 10 named storms as of late last week, including massive Hurricane Ian. Despite being past the peak of the season, there is the possibility of more tropical storm formation in the Atlantic over the next month due to the expanding La Niña. The tropical storm and hurricane season doesn’t end until Nov. 30, so we’ll have to wait and see.

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Contact Randy Mann at randy@longrangeweather.com