As of early Wednesday, I’m expecting a new weather pattern of showers and scattered thunderstorms across the Inland Northwest.
However, we’re not finished with the nice, warm weather just yet. High pressure is expected to rebuild across our region this weekend and hang around through much of next week. As we get toward the full moon on Sept. 19, it looks like we’ll have more showers and a few thunderstorms develop across the region.
It was a warm August, with an average temperature of 72.2 degrees at Spokane International Airport. That’s 2.9 degrees above normal. There were 8 days with highs at or above 90 degrees. The hottest afternoon was the 14th with a reading of 92 degrees. The coolest afternoon was Aug. 2, with a high of 61, thanks to a very chilly and wet Pacific storm system.
The rains on Aug. 2 helped to bring the monthly precipitation total to 0.68 inches. The normal for August rainfall is 0.59 inches. In Coeur d’Alene, 1.94 inches of rain fell thanks to numerous thunderstorms that missed the Spokane area.
As of early September, sea-surface temperatures near the west coast of South America are still 1 to 2 degrees below normal, indicating a very weak La Niña . However, temperature moderation near the South American coastline in recent weeks points to a weakening of this cooler than normal sea-surface temperature phenomenon. Many computer models predicted that our current La Niña would weaken during the fall.
During La Niña years, we often see average to above normal snowfalls across the Inland Northwest, especially over the mountain regions. During the record snowfall years in the late 2000s, we had a rather strong La Niña pattern in the south-central Pacific Ocean combined with very low sunspot activity.
If La Niña manages to hold on to life over the next several months, I am predicting a slightly colder and snowier winter season for the Inland Northwest.
Our upcoming fall weather looks wetter and cooler than normal beginning around the middle of October. However, if La Niña falls apart sooner than expected, then conditions may not be as wet later in October and November.