Extreme heatwave in SW United States

That's not far short of 50C

Dangerous heatwave settles over U.S. Southwest- temps to hit 120 F in Arizona

A ridge of high pressure will cause elevated temperatures across most of the Western United States, from Arizona and California, northward to the US/Canada border. This also may bring the first monsoon storms to the region as this abnormally large ridge of high pressure takes hold.

Space Weather

26 June, 2013

It’s that time of the year again, where a hot desert meets the Summer.  Temperatures in the 100s across Phoenix will turn to 115+, with 120+ along the Colorado River Valley as a ridge of high pressure builds in the area.

This ridge will be very large, bringing temperatures 15-20 degrees higher than normal for Arizona, California, Oregon, Washington, Idaho, New Mexico, and Utah.  Other areas like Montana, and Wyoming may also be in the outer fridges of the heatwave ridge.

With that heat will bring monsoonal moisture into play, California, Nevada, Arizona, New Mexico, and Utah may see the first monsoonal thunderstorms of the season with this event.

More information will be given as the data is compiled, but if in these regions, prepare for increased heat and humidity by the end of the week and into this weekend.  There are indications this lasts through next week as well.