One of the oddities of Northwest meteorology is that westside fog/low clouds and eastside smoke are often directly related.
Yesterday was a good example. To illustrate, consider a series of visible satellite images from yesterday and this morning.
Yesterday morning at 9:45 AM there was lots of low clouds along the Washington coast and just a hint of smoke from the Pioneer Fire on northern Lake Chelan.
But by 7:45 PM yesterday evening, the smoke from the Pioneer fire had exploded, with the plume heading eastward. Clearly, strong westerly (from the west) winds were present.
To demonstrate that the Chelan fire was the only fire act in town, here is the satellite-based fire emission map from yesterday--lots of orange dots (fire locations) near Chelan indicate the fire.
So what happened? The west-east pressure difference increased (higher to the west) as cool/dense marine air pushed into western Washington. This is associated with the upper-level ridge of high pressure moving inland.
This westside push of marine air and increased pressure diffenence across the Cascades resulted a substantial strengthening of the winds above the eastern slopes of the Cascades.
To illustrate this, here are the winds at Ellensburg (times in PDT). Big surge of winds there yestergy, with gusts nearly getting to 40 mph.
Take a look at the max winds yesterday across the region (below). Pretty windy over the eastern slopes and downstream of the Columbia Gorge. No wonder wind energy is up.
This is turning out to be a very benign fire season so far, with burned acreage far below normal. Importantly, the latest model runs suggest no heatwaves over the next week.
Cliff, you may need to give us your definition of "heat wave". Maybe you don't call it a heat wave for the west side but in Wenatchee we have had temperatures near or over 100 for the past 10 days, with only one day since July 4th being below 100 (the average maximum for the past 10 days is 102 for the Tree Fruit Research Center). And it looks like we will be up near 100 or higher through this coming week. Yes we have had only one big fire so far (Chelan fire) but that one is getting quite large and will likely end up much larger before it is out. While fires so far may not be numerous, the potential for fire is now very high and if we get dry lightning or any type of ignition, we could have many more fires to deal with.
ReplyDeleteMy experiences with most fires in the Lake Chelan area are that once a fire starts and escapes initial attack, about your only option in the hot, dry windy weather conditions that usually occur, is to stand back and wait for either the weather to change or the fire to run out of fuel. It is too remote and rugged to attempt direct tactics. There are no roads anywhere near the Pioneer fire at this time, only hiking trails. The nearest roads down lake from the fire are below Safety Harbor creek, and the fire may get to that area before it is over. The possibility of dry lightning is of most concern now since these fires often start in more remote areas harder to access and there may be so many starts that it overwhelms the initial attack efforts A good example of this was the 1970 fires in the Wenatchee and Okanogan.
DeleteYup. In the last few frames of visible satellite tonight we are seeing exploding smoke plumes also from the Ashcroft complex of fires. Bye bye blue skies
ReplyDeleteWenatchee usually enjoys cooling from the Columbia River, which moderates the temperatures. So with unusual local weather patterns, that cooling can presumably be disrupted.
ReplyDeleteLooks like Seattle will break the record of consecutive 80+ days. I wonder how much hotter August will be since it is the hottest month of the year.
ReplyDeleteSummertime temperatures can be slightly cooler right next to the river in Wenatchee when the breeze comes off the river, however both main temperature observation points for Wenatchee, the Tree Fruit Research Center and Pangborn Field, are too far away from the river to be affected by it. The long term climatological site near downtown Wenatchee is fairly close to the river and may, at times when the wind is right, be slightly affected.
ReplyDelete