September arrived Wednesday, marking the start of meteorological autumn. Even though it’s the fourth warmest month of the year, it’s also a stepping stone toward the coldest time of year.
Meaning that, it’s a good month to keep shorts and T-shirts handy but to bring out the jeans and sweaters, too.
The overall air mass remains warm, so afternoon high temperatures tend to run warm as well, especially during the first half of the month. Later in the month, we tend to see more dips in day and night temperatures as the days grow shorter and nighttime inversions strengthen.
Here’s a brief look at some Septembers in Spokane:
•September 2020 was notably warmer and drier than normal, with cooler nights and a few rainfalls arriving during the later half.
•It has only snowed twice in Spokane’s recorded history during September and if you were here in 2019, you remember the most recent event. On Sept. 28-29, the city received a surprising – and for motorists and gardeners, an infuriating – 1.9 inches of snow. An even earlier snowfall of 1.4 inches occurred on Sept. 23, 1926.
•On Sept. 25, 2001, drought conditions combined with recently-plowed fields and winds reaching 40 mph that triggered a widespread dust storm in much of Eastern Washington and North Idaho, drastically lowering visibility and causing large particulate matter concentrations in the Spokane area.
•The warmest September was in 1938, when the average temperature was 67.8 degrees – 8.2 degrees above normal.
•The coldest September stretches back to 1884, with an average temperature of 52.6 degrees – 7 degrees below normal.
Being that we just emerged from a multiple record-breaking hot and parched summer, it’s hard to imagine September 2021 having unseasonably cold temperatures or snow. On Sunday and Monday of this week, some of us were cooling off with fans and air conditioners.
Not surprisingly, there’s a good chance that summertime weather will linger. September’s outlook calls for “increased chances of above normal temperatures for the entire state,” according to the office of the Washington state climatologist, especially in Eastern Washington. Also projected in our half of the state is slightly below normal rainfall, the agency said.
Most likely, the weather transition from summer to fall will be gradual. This weekend, temperatures are expected to climb into the low 80s. During the latter part of the month, they’ll probably run in the upper 60s to low 70s. Crisp air more typical of autumn – along with much-needed precipitation – probably won’t settle in until sometime in October.
Nic Loyd is a meteorologist in Washington state. Linda Weiford is a writer in Moscow, Idaho, who’s also a weather geek. Contact: firstname.lastname@example.org
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