Northwest wildfires take 'shine' out of Midwestern sunshine
The photos above show just how the skies have changed in the past week. The photo on the left showing a deep, blue sky was taken on July 6 before the big wildfires erupted. The one on the right was taken on July 17. (The puffy clouds in there are routine afternoon cumulus clouds, not related in any way to the fires.)
The upper air pattern shows winds were blowing out of the west across the Northwest, then took a dip to the south around an upper level trough then (not pictured as it's off the screen) pulled north back into the Minnesota/Wisconsin/Illinois/Michigan areas.
You can see the progression of the wildfire smoke across the northern tier of the U.S. using the high-resolution MODIS satellite:
Here it is on July 17 for the Pacific Northwest, showing where the wildfires are burning and pointing out the smoke drifting east (the hazy smudges on the satellite image):
Unfortunately, the MODIS didn't capture full scans that day for much of the rest of the region, but I was able to piece-meal these two. Here is just east of the Rockies:
And here is the Upper Midwest. Minneapolis is tough to see amid the satellite scan lines but I've highlighted it. You can see the white haze around the region there -- looks like Chicago also had a hazy, smoky day there as well.
An approaching trough Tuesday into Wednesday will shift the upper air winds more southerly where the smoke will likely soon be carried into southern B.C., Alberta and Saskatchewan.
We're hoping that trough will bring some badly-needed rain to the wildfire regions as well, but the rain may come with a price of more lightning with strong, erratic winds near storms and heavy rain that could trigger flooding in burned out areas.
(Here is KSTP's story on the wildfire smoke in Minneapolis:)