Wet and windy weather will continue in the Walla Walla Valley for the next couple of days before a calmer regime becomes established here for the end of the week and the coming weekend.
A chain of moist and mild Pacific storms has been directed into the Pacific Northwest from the southwest over the last several days by a screaming 140-knot jet stream overhead, whose blustery winds have occasionally mixed down to the surface to provide umbrella-inverting gusts that neared 40 miles per hour at times.
Locally, precipitation amounts have not been that impressive, with barely one-third of an inch of rain recorded at Walla Walla Regional Airport in the week ending Monday morning. But where that moisture-rich river of maritime air has butted up against the mountains, copious amounts of rain and snow have fallen, resulting in a wide assortment of National Weather Service watches and warnings for heavy snow, flooding, avalanches and rock- and mudslides for the Coastal Range and the Cascades of Washington and Oregon. Road closures in central and western Washington caused by these various perils, as well as snowmelt from previous snowfalls, were legion over the holiday weekend. With another strong storm knocking on the door for this afternoon and tonight, those threats will almost certainly continue.
Three feet or more of new snow above 3,500 feet in the Cascades has dramatically improved the state’s snowpack, but the new snow on top of unstable old snow, coupled with the very strong winds, has increased the threat of avalanches to an extreme level. Several of these have already proven fatal to those who had the misfortune of being in the wrong place at the wrong time in the high country of the West, where orographic lifting has enhanced the precipitation amounts falling in the high country. When a moist flow of air is forced to rise as it encounters elevation, cooling and condensation of that moisture leads to greatly increased amounts of precipitation where that occurs.
For a region that was suffering under the burden of a looming drought, this recent string of storms, which has brought a new round of rain and snow to the Pacific Northwest every 24-36 hours, has been a real godsend. Unfortunately, as happens with mind-boggling frequency, the “cure” sent to us by Mother Nature may end up as bad as the disease, with the balance now tipping strongly for some locations in the direction of too much too soon. Our Valley, however, could certainly use more rain and snow as we plod along through February toward the spring growing season.
The final chapter of this stormy saga will write itself tonight and tomorrow with a cold frontal passage that will eventually put an end to this round of inclement weather. Cooler air behind the front will ultimately shave off a good 10 to 15 degrees from our high temperatures, which have risen well into the 50s under the influence of the persistently strong southwesterly flow aloft. A fairer and drier period of weather under strengthening high pressure will commence on Thursday and last into the weekend, though the mountains may see occasional clouds and a bit of rain or snow as the flow backs toward a more northwesterly direction. Highs should reach the upper 30s and low 40s, which is just a little shy of the seasonal norms of around 45 degrees.
In the longer term, the 16-day Global Forecast calls for a continuation of mostly fair weather next week with no further precipitation expected until the very end of the month or the beginning of March. Last week’s dalliance with temperatures near 60 degrees, which had visions of golf and gardening dancing in peoples’ heads, might seem as if it all was dream at this point, but more days like that are just around the corner. Now, if we can just hang on for a few more weeks.
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.