All-time record highs may fall in the Desert Southwest

KMSP - While many around here constantly tout that the hot weather in the Southwest U.S. isn’t that bad because it’s a “dry heat”, have clearly never lived there.  As a former Phoenician, I can tell you that while it may be a dry heat this time of year, 120°+ is far from comfortable.  You can find the “dry heat” in a fireplace too, but you don’t choose to stand in it do you?  Well, same goes for the extreme heat in the Desert.  While some may argue that it’s more bearable than the humidity, I can tell you that it still feels like you’ve suddenly been transported to the surface of the sun.

That’s where temperatures are headed in parts of California and Arizona this week.  Widespread 110°+ temperatures are expected from Tucson Arizona to Redding California with all-time record highs in jeopardy.  The mercury has only hit 120° 3 times in Phoenix since the late 1800s, Tuesday could be the 4th.  Flagstaff has never hit 100°, but they will be pretty close.  While one of the hottest places on Earth, Death Valley, will likely stay shy of the all-time record, 130° is certainly attainable. Temperatures have only cracked that mark about a dozen or so times in its century of record keeping.

While the heat can be dangerous in obvious ways like dehydration and heat stroke, it can be equally as dangerous for those headed to the airport.  Hot air is less dense than cold air.  The hotter it becomes, the less mass the air has with it.  An airplane needs a certain amount of mass moving at a certain speed to be able to create lift under the wings and allow the plane to fly.  Well, the warmer it gets, the faster that plane has to go to get the amount of lift it needs to soar.  But runways at our nation’s airports are only so long, and can’t be lengthened for the really warm days.  So when the temperature gets roughly to 120°, runways aren’t long enough to allow aircraft to take off safely, so they are grounded until temperatures cool.  For places like Phoenix, this could be a solid 2-4 hour chunk of the afternoon.  American Airlines has already set up travel waivers for those flying Monday – Wednesday afternoon if flights are cancelled because of the heat.  Other airlines will likely follow suit if it becomes an issue.