Our mid-April weather has been peculiar, just as it was in 2016. But for completely different reasons.
Unless you’ve been vacationing on the beaches of Maui, you know how exceptionally chilly it was recently across the Inland Northwest and the entire Pacific Northwest, for that matter. Some locations are emerging from the coldest mid-April in the region’s history.
In the Spokane area, daily temperatures ran an average of 15 degrees below normal. From April 10-15, all but one day (April 13) set records for the coldest high temperature for those dates. Highs reached only 38 degrees on April 11 and 14 – a temperature more in line for an overnight low.
The region also saw remarkably colder low temperatures. On April 15, Wenatchee dropped to 23 degrees and Ephrata to 19, setting coldest low-temperature records for April, according to the National Weather Service in Spokane.
But cold air alone doesn’t produce snow, and man, did it snow.
“Snowing in Spokane… and it’s April 14. Insane…,” the Washington State Department of Transportation posted in a Tweet advising motorists to drive carefully.
Snowfall, which began that evening, measured 1.5 inches at Spokane International Airport, breaking the daily record for April 14 that was previously set in 1955 when 0.5 of an inch accumulated. Intermittent snow fell overnight into Friday, April 15, and then started up again later last Saturday . Hardest-hit areas included parts of the Palouse, Coeur d’Alene and Hayden, where up to 6.8 inches fell. Meanwhile, schools and businesses shut down for a day in Portland when the city experienced its first April snowfall in recorded history.
Why was springtime placed on hold? A deep trough of low pressure allowed cold air in the upper atmosphere to spill south from Canada over the Pacific Northwest. Once the cold snap was in place, snowfall was generated by moisture-packed clouds and an unstable air mass.
Which is the polar opposite of what happened six years ago. In mid-April 2016, we saw an unusually early heat wave. In fact, most of the month was freakishly warm. In Spokane, only the Dust Bowl year of 1934 was a warmer April than in 2016. The month recorded three straight days with temperatures above 80 degrees and six straight days with temperatures above 70 degrees.
Spokane’s hottest day occurred on April 20, when the mercury surged to 85 degrees and broke an all-time daily record for the city. Another record was shattered on April 21 when the low temperature topped out at 56 degrees.
During the month, two separate ridges of high pressure formed off the West Coast that kept storm systems away. At the same time, hot air flowed into the region from the Desert Southwest. As you can see, it was a much different weather pattern from what we’ve seen this month.
Speaking of which, we got a breather from the cold, snowy weather on Easter Sunday when the spring sun returned, temperatures increased to 48 degrees and snow melted away. While bouts of cool, damp weather are expected throughout April, conditions won’t be extreme like last week.
Furthermore, this weekend is shaping up to be fairly pleasant, with highs approaching 60 degrees.
In other words, winter appears to have taken its final breath.
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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