Warmer early-season temps due to spring back to normal



Wikimedia Commons photo

Powdery mildew growing on grapes.

Your wandering weatherperson has returned from his pilgrimage to the East a few pounds heavier than he departed, with a renewed appreciation of his Maryland roots — particularly in the culinary realm. If there is anything better in this world than crab cakes and a hot corned beef sandwich on rye (with mustard, of course), your forecaster has yet to encounter them.

And speaking of the truly wondrous, he was absolutely stunned to deplane in Pasco on Saturday afternoon in bright sunshine and a temperature hovering close to the 70-degree mark. Spring has finally waved its magic wand over eastern Washington, and the result is totally enchanting!

In just a matter of eight or nine days since his departure, our part of the world has been transformed, and the drab grays and browns of a too-long winter have been miraculously replaced by a springtime riot of dazzling yellows, pinks, whites and greens that is an enormous treat for winter-weary eyes.

Buds have broken in many of our local vineyards, so the frost watch is on. Cutworms will be doing their nefarious nocturnal work on these mild April nights, additionally increasing the need for viticultural vigilance on the part of our vineyard managers — some of whom have already begun to treat for that annual scourge known as powdery mildew (Erysiphe necator).

This fungus lurks in all vineyards, and its overwintering structures, called chasmothecia, await only a splash of rain and temperatures exceeding 50 degrees to loose a barrage of spores which are dedicated solely to infecting any green grape tissue upon which they land.

These new infections will then go on to produce spores of their own within seven to 10 days under optimal temperatures — between 70 and 85 degrees. This makes it a season-long problem for grape growers, one that demands a great deal of a viticulturist’s time and effort — not to mention money — to control.

Fortunately, in the short term, neither frost nor rain appears to be a likely occurrence here in the Walla Walla Valley. The continuing influence of a broad area of high pressure, fair skies, light winds and mild to warm temperatures should be the rule for our area until the latter part of the week, when a couple of low pressure systems from the Pacific will begin to affect Washington state with increasing clouds and a chance for showers, beginning Thursday and continuing through the upcoming weekend. At that point, our afternoon readings will begin to cool back into the low- and mid-60s which is more congruent with our seasonal normals for early April.

According to the 16-day Global Forecast System outlook, the cooling trend should persist into next week, and it may be some time before the Valley sees 70-degree temperatures again, as a westerly flow brings a succession of systems through eastern Washington with varying amounts of cloudiness and periodic rain chances.

Regrettably, the best chance for rain appears to coincide with the weekend of April 13 and 14, when Feast Walla Walla will be in full swing downtown. Temperatures that weekend are forecast to cool even further, with highs possibly struggling to crack 60 degrees.

The return of warm weather brings with it a few time-honored traditions, like baseball, the backyard barbecue and lawn mowing — an activity which occupied part of your forecaster’s weekend. Each year, the battle gets tougher, and this year’s new grass seems to have been working out clandestinely in the off-season, prepping for the annual warfare that began on Sunday. Your weatherperson, still nursing a bum wheel, finds himself at a distinct disadvantage this year.

Unfortunately, the combination of recent precipitation and mild temperatures has provided the grass a surge of growth that may allow it to gain a temporary early-season upper hand, but with newly sharpened blades, and a keener sense of resolve in your weatherperson’s arsenal, that advantage may be as fleeting as the spring showers that will fall here at the end of the week.

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 jeffrey.popick@wwcc.edu.


Use the comment form below to begin a discussion about this content.

Sign in to comment

Click here to sign in
4 free views left!