Friday, May 1, 2015

Continued warm, dry weather increases drought concerns across Washington

By Camille St. Onge, Communications Manager, Climate Change and Air Quality

The weekly drought report released by the Office of the Washington State Climatologist and the Washington Department of Ecology showed that Washington had very little precipitation over the last week.

Although northern Puget Sound and parts of the Olympic Peninsula and central Sound received normal- to above-normal precipitation between April 22 and April 29, nearly the entire state is lacking normal amounts of precipitation. And, Washington is forecast to see above-normal temperatures and below-normal precipitation in the next two weeks.

Regional weather conditions April 22 – 29, 2015

Olympic Mountains and Peninsula

The northern Olympic Peninsula had near-normal temperatures and precipitation over the last week. Though precipitation was near normal, it’s important to note that we’re getting to the direr time of year.  That means those normal precipitation amounts are significantly less than the rain and snow we receive in the winter months. Thus, “normal” precipitation does not provide much drought relief.

The chart below shows monthly accumulated snowpack for the last few water years (October to September) compared to normal in the Olympic Mountains. This information reveals how serious the lack of snowpack is.

The region has not had any snowpack accumulate since January, and remains far below average. 

Western Slopes of the Northern Cascades

Whatcom and Skagit counties received above-normal precipitation over the last week (150-200 percent of normal) with temperatures on the cooler side. Bellingham Airport, for example, received 0.59 inches in the last week, 0.04 inches above normal.

Despite these short-term wetter conditions, in the last 30 days there has only been between 50 and 90 percent of normal precipitation in the area. The precipitation is shown in the hydrograph from the Nooksack River near Deming in the chart [below?]. It illustrates the streamflow in the last few days has been closer to normal than at any other time in the last two weeks.

Chelan/Kittitas/Yakima Region, Walla Walla Watershed, and Okanogan

These three regions were all drier than normal over the last week. 

These warm and dry conditions were part of the reasoning to extend the area of “severe drought” into Walla Walla and the Lower Columbia Basin in the U.S. Drought Monitor shown

The Yakima Bureau of Reclamation reservoirs are now being tapped into. This is evidence that impacts from the low snowpack are starting to be felt.  Both snowpack monitoring stations in the Walla Walla basin measured no snowpack in the last few days. That is approximately a month earlier than usual. 

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