What a terrific Thursday it was one week ago . Puffs of white clouds floated against sapphire skies as the mercury rose to the warmest temperatures of 2021.
It was May 6, and Spokane and Coeur d’Alene reached 83 degrees, and Lewiston-Clarkston notched a record-tying high temperature of 92 for that date.
Then, early that evening, foreboding clouds and wind gusts began sweeping eastward across much of Washington, Oregon and Idaho. When we awoke the next morning, we discovered the burst of summerlike warmth had taken a nosedive. A surge of cool air, lots of clouds and breeziness overtook the region.
Driving the abrupt weather change was a large cold front that arrived the night before. In 24 hours, locations across the Inland Northwest saw temperatures drop 20-30 degrees, with Spokane dipping from a high of 83 degrees last Thursday to a struggling high of 59 on Friday. Even more remarkable was the 30-degree temperature plunge of 92 to 62 that occurred in Lewiston.
In addition to much-cooler temperatures and windiness, small pockets of brief showers and lightning strikes were reported in parts of Washington and southern Idaho, along with blowing dust that reduced visibility on stretches of highways.
And talk about a coincidence. Exactly one year earlier, a cold front similarly altered our region’s weather. On May 5, 2020, the sun was shining and temperatures ran in the 70s across the Inland Northwest. Then, on May 6, we experienced a steep temperature drop accompanied by high winds, dark clouds, rain and even some errant snowflakes.
So just what are these cold fronts that so abruptly interrupt our tranquil weather? And are they more common this time of year?
A cold front marks the leading edge of a cold air mass as it approaches a warm air mass. Not only does the cold air move faster than the warm air, but it’s also denser, or heavier, giving it plenty of heft to overtake the warmer mass. Like an atmospheric plow, the cold air lifts the warm air out of the way, creating changes in air pressure and temperature that typically usher in winds, clouds and cooler weather. Rain and other forms of precipitation are often part of the mix as well.
It’s not that cold fronts occur more often this time of year; it’s that they’re more noticeable. One day people are clad in shorts and T-shirts and dipping a toe in lakes and rivers. The next day, those same people are wearing coats and clutching their hats as they walk into a brisk wind. The difference triggers a bigger jolt than a cold front sliding through in December when many of us are accustomed to wearing winter clothes and spending more time indoors.
Keep in mind that “cold” is a relative term. We still get cold fronts in summer, but it might mean a temperature drop from 90 degrees to 80. Noticeable, yes, but not nearly as much as the 24-degree drop Spokane experienced last week.
Last week’s cold front gave way to several days of cooler, blustery weather that didn’t let up until Tuesday. Unfortunately, we didn’t get widespread rains needed to offset the growing drought conditions caused by an unusually dry spring. What we got instead were some chilly mornings, with temperatures dipping to a low of 36 degrees in Spokane, Coeur d’Alene and Pullman on Saturday. Just north of Spokane, Deer Park dropped to 32.
But it is May, after all, and warm weather was destined to return. The temperature reached 70 degrees in Spokane on Tuesday, inching upward through the workweek. Temperatures are expected to run in the mid-70s with a mix of sun and scattered clouds throughout this weekend.
Nic Loyd is a meteorologist in Washington state. Linda Weiford is a writer in Moscow, Idaho, who’s also a weather geek. Contact: email@example.com
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