Despite coolness, temperatures still above normal
Mother Nature couldn’t decide whether to shift into fall or hang onto summer this past week.
Chilly morning temperatures resulted in frosty and freezing conditions in many areas of the Inland Northwest last Monday. Temperatures fell to the freezing mark across a few spots within Coeur d’Alene and dipped as low as 32 degrees in Sandpoint, 34 in the Pullman/Moscow area, and 26 in Deer Park.
Low temperatures in Spokane had a wide range, from a chilly 30 degrees at the National Weather Service Office to a mild 42 degrees at the nearby Spokane airport and a cooler 37 degrees in Spokane Valley.
And you wonder why it’s difficult to forecast temps around here with such extreme variation within relatively short distances!
Weather quickly did a 180, however, with record to near-record highs in the upper 80s and lower 90s across the region on Wednesday. Temperatures have cooled off but still remain 5 to 10 degrees above normal for this time of year.
One of the changes we’ll start to see, now that we are “officially” in the fall season and moving into the month of October, is a more active weather pattern due to the southward progression of the polar jet stream. During the summer, the polar jet spends most of its time north of the Canadian border. This fast-moving current of air (which during the winter can contain wind speeds of 200 to 300 mph) plays a part in our weather by supplying energy to the circulation of surface storms as well as directing their paths. Though the jet stream resides high in the atmosphere at altitudes of 25,000 feet above sea level and higher, it is a reflection of a strong temperature gradient at the surface. Surface fronts are situated at the leading edge of these tight temperature gradients, and the progression of these fronts often bring unsettled weather to the areas as they sweep past.
Our shift into a cooler, more unsettled weather pattern will be slightly tempered by the intensifying El Niño which is expected to be of moderate strength. Warmer- and drier-than-average weather is expected for much of the Northwest through at least October. Signs continue to point to below-average snow for the valleys this winter.
Another statistic that remains well below average is the number of Atlantic hurricanes this season. Peak hurricane season usually runs from early to mid-September. As of Sept. 23, all was quiet in the tropical Atlantic. The only storms reported for the month have been weak Tropical Storm Erika, and Category 3 Hurricane Fred, which fortunately was not responsible for any fatalities.