June has been exceptionally hot in the Southwest.
Las Vegas went eleven consecutive days with a temperature of 110 degrees or greater and a total of 17 days in the month. Phoenix has been 110 or higher all but three days, including 119 on June 20. Death Valley has been as hot as 127 twice.
All of this is much warmer than average at a time when the Desert Southwest usually has its hottest temperatures of the year. The extreme heat this June is due to a persistent upper-level high pressure area which causes clear skies very hut surface air temperatures due to a process called compressional heating, in which downward-moving air is compressed near the ground.
These sorts of southwestern heat waves have been known to move into the Great Plains, bringing hot weather but not usually as hot as 127 degrees! There is potential for some very warm days in our region next week from the remnants of this weather system.
