The National Weather Service in Flagstaff says strong high pressure will affect Arizona this week, with very hot temperatures for lower elevation areas. An Excessive Heat Warning is in effect until 7-PM Wednesday for the Grand Canyon below 4000 feet elevation. This includes the Colorado River and Phantom Ranch. Highs elsewhere will remain close to 10-degrees above seasonal averages into the weekend. Limited moisture will return to portions of northern Arizona by Wednesday and Thursday, bringing a slight chance of showers or thunderstorms and possibly some relief to the heat for a few higher elevation locations.
