ASHLAND, Ore. — Climate researcher Greg Jones confirmed Tuesday what many in the Pacific Northwest wine industry wondered — this corner has been the coldest region in the country in some respects. And that’s led to a slow start to the 2017 vintage.
“The general pattern in temperatures across the U.S. continued from January into February. The PNW remained the coldest area with temperatures 1-5°F below normal in eastern Washington and Oregon,” the Southern Oregon University professor wrote in his latest report to the wine industry.
Other parts of the nations have been warming more quickly as spring approaches. Areas of the Rockies reported temperatures 3-7 degrees Fahrenheit above normal.
“The rest of the country was much warmer than normal for the month with the bulk of the U.S. seeing 5-9°F above normal and widespread reports of very early spring phenology including cherry blossoms in D.C. peaking now through mid-March,” Jones wrote.
Precipitation experienced along the West Coast made headlines with Oroville Dam overflowing and prompting evacuations. Areas of the Pacific Northwest were among those with amounts as much as 400 percent above average snowfall.
“Winter precipitation amounts in the western U.S. continue to erode away at the drought zones of the past few years,” Jones wrote. “The most recent Drought Monitor shows that drought conditions continue in central to southern California, but have been moved to mostly moderate status. Drought conditions have developed further in Oklahoma, across New England and the Southeast, but the overall extent and intensity of the drought conditions as lessened in each area.”
Accumulations of snow also delayed pruning of vines in many areas of the Pacific Northwest.
La Niña turns to neutral
Jones points to the large pool of cooler-than-average ocean temperatures across the North Pacific as the key reason for cool start to 2017.
A year ago, the 2016 vintage was off to a record start. On Feb. 8, 2016, the Paradise Jackson Visitor Center at Mount Rainier National Park reported a high of 71 degrees.
“Sea surface temperatures (SST) in this area are running 4-5°F cooler than average and 7-10°F cooler than last year at this time,” Jones reported.
Meanwhile, waters in tropical region of the Pacific are warming.
“Colder than average waters in the tropical Pacific have waned and La Niña conditions are no longer present (termed neutral),” Jones wrote. “Most models predict the continuation of neutral conditions through the Northern Hemisphere summer.”
Frost looms as threat to 2017 vintage
For the Pacific Northwest, La Niña conditions led to the wet and cool start to the 2017 vintage.
“Unless something else develops, the cooler SST off the West Coast and out into the North Pacific would point to a greater chance for a cooler and later spring than we have experienced in a while,” Jones wrote. “Statistical and dynamical analogs have this year currently looking like what we experienced in 2012.”
According to the 90-day projections, the rest of the country is expected to be warmer than normal, but Pacific Northwest growers might need to remain vigilant longer regarding frost protection leading up to Mother’s Day — the traditional yet unofficial last weekend to worry.
“Or in other words, this region will likely see close to normal spring temperatures with a normal spring frost season, which is quite a difference from the last few years when there was little to no spring frost at all,” Jones wrote.
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