(Wines&Vines) - Just six months ago, growers in Washington state were discussing vintage variation with respect to cool years. Today, with wildfires ripping through tinder-dry swaths of Eastern Washington and growing degree-days outpacing the long-term average, growers are wondering how grapes will fare post-véraison.

While drought conditions in many parts of the state have been of little direct concern to growers, the early accumulation of growing degree-days underscores reports that estimate the vintage at three or more weeks ahead of schedule.

Prior to April 1, the weather station at Washington State University in Prosser racked up 91 growing degree-days—four times the long-term average of 23.

The trend has continued since then, with 1,103 growing degree-days on the books versus 882 in 2014 (the benchmark for a warm year) and the long-term average of 791.

The phenomenon was spurred not only by an unusually warm, dry winter that saw some growers sending pruning crews into vineyards in early February, but blasts of temperatures above 100° F in early June and again this week.

Vines have grown wildly, but with cluster formation taking place, the question for Michelle Moyer, an assistant professor and extension viticulturist at WSU in Prosser, is the timing of véraison.

“We have no idea when véraison is, “ she told Wines & Vines this week. “If it’s super-hot like this, plant development will slow down, and it may just sit there and then start the normal development process in August again.”