This was a very windy period over parts of eastern Washington due to the large pressure differential over the Cascades (higher pressure in the west, lower pressure in the east).
Today’s maximum winds since midnight (see below) reached 51 mph near Ellensburg. Winds were mainly strong near and downstream of Ellensburg and east of the eastern terminus of the Columbia River Gorge.
A forecast model for this afternoon shows two main winds east of Washington. One east of Cle Elum and Ellensburg and the other downstream of the Columbia Gorge (stronger winds are shown in blue and green).
So why are the strong winds east of Washington local?
It concerns the variable heights of the Cascades and specifically the two lower zones in the north-south fence. Below is a topographic map of Washington and northern Oregon, with green representing lower elevations. Note that there are two lower areas across the Cascades: Columbia Gorge near sea level between Oregon and Washington and the “Stampede Gap” region of central Cascades (with the lowest elevation around 3000 ft), which also includes the Pass. Snoqualmie.
Both are indicated by red arrows.
As a high pressure develops over the Cascades, with higher pressure to the west and lower pressure to the east, winds will blow through these gaps, creating two large westerlies east of Washington. A slight wind may also be generated downstream (east) of Stevens Pass.
The winds escaping these Cascades strengthen in the evening after daytime temperatures in eastern Washington drop there (and thus increase the pressure differential across the Cascades0. To illustrate, below, below. is the wind forecast for this evening (in mph) ..more trees east of Washington, means stronger winds.
With high/cool pressure west of the Cascades over the past few days, the pressure pattern is very favorable for a steady westerly wind blowing through the wind turbines east of Washington, creating a high wind energy supply potential. continuous (see Bonneville stats below, wind plus solar shown with green line).
As noted in my previous blog, the total amount of wind and solar accounts for about a third of the demand
(red line). Hydropower production (blue line) has been allowed to decrease due to abundant wind power.
The latest projections suggest that the west will warm and therefore wind power will decrease significantly over the next few days.
