The Pacific Northwest wine industry won’t soon forget the snow and cold of February, and yet the 2019 vintage is off to a warm start, according to data gathered by climate researcher Greg Jones.
As the month of May began, growing degree days throughout the Northwest were ahead of the historically hot 2015 vintage, although bud break in Oregon and Washington has been slightly behind normal, about five to 10 days behind.
“Heat accumulation (GDD) amounts for four locations that I have tracked for many years in Oregon are all above the 1981-2010 normals for the month of April and are above the same time in 2018, which is similar to what was seen in 2015,” Jones wrote.
Jones, one of the wine world’s foremost figures in climate research, is director of the Evenstad Center for Wine Education and Evenstad Chair in Wine Studies at Linfield College in McMinnville, Ore
“The temperature forecast for May through July continues to indicate the likelihood of a warmer than average western U.S., while precipitation is forecast to be near average south and lower than average in the PNW,” Jones summarized May 3 in his latest Weather and Climate Summary and Forecast.
Soon after, the National Weather Service forecast a record-setting high of 82 degrees on Friday, May 10 in Seattle. That is 20 degrees above normal.
Walla Walla Valley station tracks ahead of 2015 vintage
Growing degree day charts in 2018 were headed in record territory on June 1, however conditions cooled.
In the Walla Walla Valley town of Milton-Freewater, Ore., there were 139 GDD through April 30. At the same stage in the record-hot vintage of 2015, there were 123 cumulative growing degree days.
Washington State University’s AgWeatherNet charts growing degree days via its 177 stations across the state as well as parts of Oregon
Through April 30, there were 147 growing degrees days recorded at the Wahluke Slope station. A year ago, it charted 132 GDD. During the 2015 vintage, it stood at 158 when May began.
At the Benton City station near Red Mountain, there were 177 GDD recorded. A year ago, it read 139 GDD. In 2015, there were 139 GDD.
On Snipes Mountain in the Yakima Valley, there were 142 GDD registered. A year ago, the accumulation stood at 118 GDD. During the blistering 2015 season, it was 133.
The Pullman school’s station in Woodinville collected 34 GDD, compared with 54 GDD last year. Back in 2015, it received 51.
In the Columbia Gorge, Skamania County’s Stevenson station notched 119 GDD. A year ago, it stood at 110, but in 2015 it stood at 107.
Frost fears pass with Mother’s Day
Mother’s Day serves as an anecdotal marker on the calendar in the Pacific Northwest as the end of frost concerns.
“The short-term forecast calls for a building high-pressure ridge over the eastern North Pacific and western North America, which should bring delightful May conditions; dry and warm with less than average frost potential except on the coldest sites,” Jones wrote.
His May report echoes the concern about the availability of water. Klamath County in Southern Oregon reported its first wildfire of the season, a 400-acre blaze called the Bray Mill Fire. Officially, wildfire season doesn’t begin until June 1, but memories of the Klondike Fire, which scorched more than 170,000 acres last year, remain fresh.
“Some concern for short to long-term drought still exists in the PNW as the May through July forecast shows,” Jones wrote.
Water year precipitation is moderately drier than average in northwestern Oregon and Washington, with the northern portions of Washington, Idaho and Montana running 60-85 percent of average. And the North Pacific remains a focal point for researchers
“The Pacific continues to remain much warmer than average,” Jones wrote. “Regional forecasting agencies are continuing to say that the overall warmth of the Pacific will likely to enhance the normal weather/climate patterns in the West during weak to moderate El Niño years. However, if coastal upwelling persists along the central California coast then there remains the potential for slightly cooler conditions into the summer.”