A quick glance at the National Weather Service's site this afternoon shows almost no weather going on across the country. It's a gorgeous, warm May afternoon for a huge chunk of the U.S. The only problem is that this lack of active weather is a breeding ground for wildfires.
The term "wildfires" is all-encompassing and covers everything from a small grass fire to acres upon acres of forest going up in flames. These dangerous events thrive when four conditions are present: dry fuel, dry air, gusty winds, and warm temperatures.
In all of the counties shaded in that fuchsia-ish color on the map above, all four fire weather conditions are present. The shading indicates a "red flag warning," which is issued by the National Weather Service when weather conditions are favorable for the formation of wildfires. In these areas, any fires that form also have a high risk of spreading rapidly and becoming out-of-control, threatening the lives and property of those in its path.
This model image shows the predicted relative humidity for 3PM CDT today, and values across a large part of the central and western United States are down in the single digits. It doesn't help that much of the region under fire danger today is already in a drought, but humidity values that low allow vegetation to dry out pretty quickly and become tinder.
The humidity is usually a bad measure of moisture because it's directly dependent on the air temperature — as the air gets warmer, humidity drops, and as it gets cooler the humidity rises. The humidity is pretty telling today, though, and here's why:
A very dry heat is baking the southwest and southern Plains this afternoon, with temperature readings between 95 and 100 degrees a common sight.
On top of the extremely low humidity and warm temperatures, winds gusts across the region are approaching 25-40 MPH at times this afternoon.
Thankfully, satellite imagery taken around 1PM CDT showed no areas of smoke across the warned areas, so hopefully it will stay that way throughout the rest of the day. Any fire that develops today in the warned areas has the potential to spread rapidly and threaten lives and property. All it takes is one careless flick of a cigarette or something equally careless to start a fire, so be careful.
[Images via TwisterData and the NWS]