Our pattern of wide weather extremes continues not only in Eastern Washington and North Idaho, but everywhere else, too. After experiencing record and near-record snows during the winter and early spring, temperatures finally rose to summerlike conditions last weekend.
Average temperatures at Spokane International Airport were well below normal until highs near 90 degrees hit last Saturday and Sunday. March’s mean temperature was 3.2 degrees below normal. April was colder with an average reading of 4.5 degrees below normal. May also started off cooler than usual, but the recent heat wave pushed our average reading to nearly 3 degrees above normal as of Tuesday morning.
As temperatures were generally cooler during the spring, mountain snowpack melted slowly. As of early May, reports of up to 10 feet of snow were observed in the higher elevations. But with the recent heat wave, many area rivers and streams, especially the Spokane, Coeur d’Alene and St. Joe, rose to near or above flood stage, causing some flooding as highs soared to near-record levels.
The big rise in temperature late last week and early this week was caused by a massive ridge of high pressure. Record heat was reported in Washington, Oregon, Idaho and California. Highs surpassed the 100-degree mark in the Central Valley of California. In San Francisco, where air-conditioning is typically not needed, the mercury soared to a record 97 on May 15.
As the high pressure ridge breaks down this month into early to mid-June, we should see the return of the former stormy weather patterns. There will likely be several strong thunderstorms accompanied by lightning, heavy downpours, damaging winds and pea-size hail. Up until now, thunderstorm activity has been less than normal, but should pick up a bit over the next several months.
From the end of June through at least mid-September, there should be generally warmer than normal temperatures throughout the Inland Northwest, with a bit less precipitation than usual for this 75-day period.
Despite a few, mainly afternoon or evening, thunderstorms at times, outdoor activities should not be substantially affected by these scattered rains that, in many cases, will last mere minutes. Overall, our upcoming summer season should be dry, but not as dry as last year.
The hottest temperatures should occur sometime around the July 18-25 full moon cycle, with readings approaching or exceeding triple-digit levels. It should also be quite hot during the first week to 10 days of August with temperatures in the mid- to upper 90s. The mid- to late June period should also see a period of warm to hot weather. In a previous article, I mentioned that our coldest weather each month often occurs near a full moon. During the summer, it’s the opposite as we usually have the hottest weather near that full moon, as was the case last weekend.
The cold winter was caused by La Niña, the cooler than normal sea-surface temperature event in the south-central Pacific. Assuming La Niña continues to weaken, our fall weather pattern should turn cooler and wetter than normal. Stay tuned.
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