One of the oddities of Northwest weather is that fog/low clouds in the west and smoke in the east are often directly related.
Yesterday is a good example. To illustrate, consider a series of satellite images visible from yesterday and this morning.
Yesterday morning at 9:45am there were lots of low clouds along the Washington coast and just a little smoke from the Pioneer Fire north of Lake Chelan.
But by 7:45 pm last night, smoke from the Pioneer Fire had exploded, with the plume heading east. Apparently, strong westerly (westerly) winds had developed.
Low clouds have really crept into western Washington this morning and there is heavy smoke from the Pioneer Fire in northeastern Washington.
To prove that the Chelan fire is the only fire in town, here is a satellite-based fire emission map from yesterday – many orange dots (fire locations) near Chelan indicate the fire.
So what happened? The west-east pressure gradient increased (higher to the west) as cold/dense ocean air pushed into western Washington. This was related to the upper level high pressure ridge moving inland.
The westward flow of maritime air and the increased pressure gradient over the Cascades have greatly increased the winds over the eastern slopes of the Cascades.
To illustrate this, here’s the wind in Ellensburg (PDT). It was gusty there yesterday, with winds approaching 40 mph.
Take a look at yesterday’s maximum winds across the region (below). Winds were quite strong on the east and lower slopes of the Columbia Gorge. Not surprisingly, wind power increased.
So far, it has been a very benign fire season, with much lower-than-normal acreage burned. Importantly, the latest modelling suggests no heatwave in the coming week.
