The Walla Walla Valley received some sweet relief from the heat last week. An unusually potent area of low pressure pumped substantial amounts of moisture into many parts of Washington state, leading to a three-day reprieve from the unrelenting sun of summer 2013.
Clouds and showers on Thursday and Friday kept afternoon temperatures at levels not experienced here since the spring, and your weatherperson, for one, could not have been more pleased with the sudden change. Highs in the mid- and upper 70s both days were a good 12-15 degrees below normal for those dates. The dramatically cooler regime coupled with the absence of searing sunshine provided an absolutely delightful respite for those who had found the season’s abnormal warmth to be an increasingly enervating annoyance.
The clouds also furnished a bit of rainfall here in the form of thundershowers, with the airport receiving 0.12 inches during the inclement period. Locations to the west and north collected considerably more, and a couple of spots in the Cascades found themselves in the rather oxymoronic situation of being under a flash flood watch at the same time a red-flag fire warning was in effect. A few of those places logged over 2 inches of rain in less than an hour — a very impressive total indeed for the beginning of August, in what has been an uncharacteristically dry summer.
Walla Walla’s extremely meager two-hundredths of an inch for July fell considerably short of its normal total for the month of 0.57 inches, and was representative of the remainder of the state, which appears to have experienced one of its five driest Julys since such record-keeping began in 1895. Neither Sea-Tac nor Spokane collected any rainfall whatsoever this past month, and Paradise Ranger Station high up on the flanks of snowy Mount Rainier recorded a measly one-hundredth of an inch. The last time Sea-Tac experienced a rainless July was way back in 1951.
As might be expected, the cloudiness and moisture associated with the low did not linger long, and by the weekend, high pressure pushing in to southeastern Washington from the Four Corners region had restored things to their more usual climatological order. Saturday’s highs were 10 degrees above the previous day’s, and the warming continued into Sunday and Monday with afternoon maxima regaining the low and mid-90s under brilliant sunshine.
The heat’s return came just in time for Monday’s Food Truck Night, which offered a dunk tank for which a series of local winemakers were featured as the dunkees. Despite numerous requests for a comment, the organizers of the event declined to respond when queried about the unusually long and sinuous Disneyland-like line of would-be dunkers who had gathered for the scheduled 8 p.m. dunking.
The upcoming weekend — following several days of above-normal temperatures and fair skies — will begin to assume an aspect very similar to last week’s inclement interlude. Another low pressure system currently spinning off the coast of California will begin to make its way to the north and east, and with it will come increasing amounts of moisture and instability borne on the southerly flow ahead of it. By Friday, it appears as if enough of those two ingredients will be in place to favor the development of showers and thunderstorms beginning in central Oregon. These will gradually migrate north and east into the Blue Mountains and out over the Walla Walla Valley by Saturday and Sunday.
If the 16-day Global Forecast System prediction has any credibility, the unsettled weather may continue into the first half of next week as the low will be rather slow to move off to the east. As a matter of fact, that outlook indicated a total of as much as four-tenths of an inch of rain occurring locally by next Tuesday or Wednesday from this incoming system. Lightning associated with this event may pose a multiday fire threat for both Oregon and Washington.
A lifelong fan of both the weather and the Baltimore Orioles, Jeff Popick is an instructor at the Center for Enology and Viticulture at Walla Walla Community College and manages the school’s teaching vineyard. Send your questions and comments to him at firstname.lastname@example.org.