Stepping away from overt politics for a moment …. the header image is a portion of the Western U.S. view from by GOES-20 a couple of days ago. I’ve annotated it with phenomena of interest …. mostly the smoke from wildfires in California and Colorado. We have an eye-candy bonus from eastern Pacific Hurricane Genevieve, south of the tip of Baja California.
As of the 23d of August, the National Interagency Fire Center, was monitoring 29 “large fires”, which are defined:
- For statistical purposes, a fire burning more than a specified area of land, e.g. 300 acres, and/or
- A fire burning with a size and intensity such that its behavior is determined by interaction between its own convection column and weather conditions above the surface.”
The latter means that the fire is making its own wind circulation, including the fire tornados we’ve been seeing in videos in the last week or so, within the larger scale flow.
But large fires do more than burn; they create smoke that affect air quality in adverse ways, especially for people with asthma, COPD, and other respiratory disorders. More on that smoke below.
The smoke seen in the banner image, being moved around by the prevailing wind currents, isn’t necessarily at the surface. In this case, however, the surface effects are significant and widespread. The images below show the weather conditions over the southwestern U.S. and eastward into the Rockies and western Great Plains.
The “infinity” symbols to the left of the station location is for haze, while smoke is indicated by the stick figure smokestack, as shown below. Visibility in miles is shown to the left of the smoke or haze symbols. The lower the visibility, the greater the smoke or haze.
Visibilities in the central valley, and even near the coast, are restricted by haze and smoke to as low as 1 mile. Southern ID, from 500+ to 670 miles away from the fires, has visibilities as low as 3 miles.
The graphic below shows today’s (8/24/20) warnings over the U.S. I’ve highlighted the areas where wildfires are resulting in air quality alerts, and where red flag warnings have been issued. There is some overlap.
The forecasts call for conditions favorable for wildfires through Wednesday over much of the area currently being affected.