Steady precipitation that has set records and caused minor flooding in some parts of the Northwest this spring bodes well for this summer's irrigation water supply forecast.
That's according to Scott Pattee, a water supply specialist with the U.S. Department of Agriculture.
Even so, he says the mix of heavy precipitation and warm temperatures this spring have made water forecasting a difficult proposition.
"Ode to the roller coaster ride called spring. One week it's record breaking sun and high temperatures, another it's record breaking rainfall and just for good measure let's throw in a few snow flurries as well," Pattee said.
He says cooler temperatures of late have slowed the snowpack's melting. As of June 1, the snowpack was 182 percent of average for the state, or nearly twice the levels typical for this time of year.
Closer to home, the snowpack is 161 percent of average in the Lower Yakima Basin and 156 percent of average in the Upper Yakima.
Pattee cautions the public those levels will soon drop based on predictions of abnormally warm and dry conditions for most of the Pacific Northwest this summer.
"Current percentages should be used cautiously as analysis using percentages this late in the season could cause bias in the outcome," he says.
Pattee and the USDA's best estimate for the Lower Valley is that the Yakima River's streamflow volume near Parker will most likely remain at about 102 percent of average through September.
The agency also estimates there's a 50/50 chance the Lower Yakima River will see streamflows at 119 percent of average, or about 20 percent more than the area typically sees.
Those figures are well below the percentages in play now, but still indicate local irrigators will enjoy a full water supply this summer.