Washington’s hottest August on record worsened precipitation deficits, leading to more than half the state being classified Thursday as in “moderate drought,” according to climatologists.
California and Oregon also sweltered through record-hot Augusts, but they were wet compared to Washington. An unusual and persistent atmospheric condition off the coast has blocked the Evergreen state from getting its normal summer splash of moist and cool air, Washington State Climatologist Nick Bond said.
“I think we’re seeing it kind of fade away. I say that with some hesitancy because the atmosphere has a lot of tricks up its sleeves and doesn’t always play fair,” he said.
The National Oceanic and Atmospheric Administration on Thursday released its August review of U.S. weather, while the U.S. Drought Monitor issued its weekly report on drought conditions.
Washington’s average temperature for the month was 5.2 degrees above normal, while Oregon’s was 5.9 degrees. California’s average temperature was 4.1 degrees above normal, tying August temperatures from 1967 and 2012. Idaho saw its 11th hottest August on record.
Some 19 percent of Idaho and 8 percent of California were in drought, little changed from the week before.
In Oregon, drought conditions were noted for the first time this summer. The northwest corner, making up 13 percent of the state, was in moderate drought.
Among all Western states, change was most dramatic in Washington. Moderate drought covered 55 percent of the state, up from 2 percent the week before. Drought touched all or portions of 34 of Washington’s 39 counties, leaving a swath of “abnormally dry” conditions over Central Washington and southeast Washington.
Assistant State Climatologist Karin Bumbaco, who contributes data to the drought monitor, said precipitation deficits are higher in Western Washington and northeast Washington than in the middle of the state, which receives little summer rain anyway.
“The change this week has been driven mostly by a lack of precipitation,” she said.
Washington had its 18th driest August on record, receiving about one-quarter the normal amount of precipitation. Oregon and Idaho received roughly half their normal rainfall. California was actually slightly wetter than average. National weather records date back to 1895.
Spring rains and melting snow swelled water supplies at the beginning of the irrigation season in Washington. The state Department of Ecology sent cut-off notices to more than 100 water-right holders in two watersheds in August, but none in the past week, an agency official said Thursday.
Most streams in Washington were at or above normal levels, the U.S. Geological Survey reported Thursday.
Yakima River Basin reservoirs, filled last spring by melting snow, held more water than usual for this time of year, according to the U.S. Bureau of Reclamation.
“If we had this summer on the heels of a dry, warm winter, it would be terrible,” Bond said.
The U.S. Climate Prediction forecast, with an unusually high degree of probability, that Washington, Oregon, Idaho and Northern California will have higher than normal temperatures for the rest of September.
Bond said the hot summer may be a “taste of the weather that will tend to be more common in future decades,” but it’s “not the new normal.”