An Excessive Heat Warning, which we've discussing all week, comes to fruition today at 10 a.m. and continues until Monday evening at 8. Highs will threaten existing records throughout the weekend.
The culprit: High pressure over the Great Basin, generating record heat for much of the Desert Southwest through Tuesday before breaking down and moving eastward.
Air quality under the ridge of high pressure has been in the moderate range, but we're watching for deteriorating conditions as pollutants build up.
Some positive news, the dew points are relatively dry, and will dry out further this weekend. Fire danger will increase because of the drying conditions and potential for Santa Ana winds developing.
Highs will be near record levels until Tuesday, with a cool down through the middle of next week.