But there is problem. During just the days when the east-side offers the brightest contrast to the dreary west, westerly winds descend into the Kittitas Valley, causing the stretch from Cle Elum to Vantage to become a wind tunnel, with sustained winds of 20-30 mph and gusts that sometimes hit 50.
Some folks say that in Ellensburg there is only one four letter word best for cussing: WIND. And the Ellensburg Safeway has a unique wind measuring devise for their customers.
Now I have enjoyed the Suncadia resort in Cle Elum a few times, but it is sufficiently exposed to the westerly winds that the extensive golf courses are perhaps a bit more of a challenge than novice golfers might have reckoned with. The golf pro at Suncadia is highly in demand for this insightful lessons in avoiding wind-driven hooks or slices. Here is a sample (click on picture) that was sent to me by a local golf enthusiast. Listen to his detailed instructions on the proper swing for windy conditions:
Strong westerly winds are found in this region when there is a large pressure difference across the Cascades, with higher pressure to the west. Such a large pressure different in most prevalent in the spring and summer. Why? In spring high pressure builds northward in the eastern Pacific, while the warming of the interior of eastern Washington leads to pressure falls, since warm air is less dense than cold air. To illustrate this pressure pattern, here is a 12-h pressure forecast valid 5 PM last Friday, a day when the winds were quite strong in Ellensburg and vicinity:
Air looks for the easiest path across the Cascades, and the Snoqualmie/Stampede Pass complex is the lowest route across (roughly 3000ft) north of the Columbia Gorge. Cool, cloudy days with strong onshore flow are often associated with high pressure in the west---that can juice the pressure difference and the winds.
Spring and early summer are the best times for strong winds moving into the Kittitas Valley and thus the period of best wind energy potential for the many wind turbines in the area. Unfortunately, this is the period of greatest snowmelt, streamflow, and hydropower potential--leading to contention between these two sources of clean energy. Why contention? Lack of energy transmission capability. I wish some of the stimulus money could have been used to fix this deficiency.
The UW ultra-high resolution WRF forecasts do a pretty good job in simulating the strong winds along the eastern slopes of the Cascades...here is a sample (the shading shows the sustained wind speed) and the brown lines are sea level pressure. You will note that the region from Leavenworth to Wenatchee get some winds too..they are downwind of the Stevens Pass gap...a lesser one.
The strongest winds are often east of Ellensburg on Whiskey Dick mountain--the ridge on which Puget Sound Energy has placed their Wild Horse Wind farm. Very nice visitor center there if you want to visit. Want sun and no wind? No problem. Drive down to Vantage and head north towards Quincy....the winds are less there.
Let me end with a plot of the sustained winds at Ellensburg during the past six months...they can get strong winds any time of the year...but you see the increase around March 1 and the beginning of the spring pressure patterns.
Memorial Day Weekend Outlook
No major storms.Friday and Saturday will be sunny and seasonably warm (60s).Clouds and a few sprinkles on Sunday and Monday-highs around 60.
At 12:09 PM, the squall line was evident...see the line of red colors. My gutters were overflowing at that time! The line was more intense east of Puget Sound.
At 1:21 PM, the squall line had moved north of Everett, with moderate precipitation behind.
At 2:35 PM it was the turn of Bellingham and vicinity, while the rain was over in Seattle.
Although the forecast was for showers yesterday, the strength and timing of this particular feature was not well forecast...which is not surprising. Here is the UW model precipitation forecasts for Saturday (staring 5 AM Saturday morning)--it thought a fairly strong line would occurred...but the timing was hours too late. 
The yellows are moderate to heavy rain.
This is a VERY unusual situation. Here is the 500 hPa forecast for tomorrow (solid lines) and what is known as the standardized anomaly....in standard deviations. You see we are at least out four standard deviations...this pattern occurs only once in 
These are very hard situations to forecast well...yes, we knew it was going to rain, but correctly defining and timing these bands is extremely difficult more than 6 hours ahead of time. One day.
