37 million people under alert for dangerous temperatures as October heat wave bakes California
Meanwhile, flood watches are in effect along the Gulf Coast and in Florida.
At least 37 million people are under heat alerts on Sunday as a dangerous multi-day October heat wave continues across nearly all of California.
Temperatures are expected to soar 20 degrees above normal for this time of year, into the 90s and 100s, from the San Francisco Bay Area to the Mexico border.
In some areas of California, especially urban areas, warm nights will provide little to no relief.
Heat alerts, advisories and excessive heat warnings are in effect for much of the Golden State.
An excessive heat warning has been issued across Southern California, including for the cities of Los Angeles, Riverside and Temecula, where highs are expected to be in the triple digits on Sunday. San Diego, also under an excessive heat warning, is expected to see temperatures reach the upper 90s.
The extreme heat warnings in Southern California will remain in effect until 8 p.m. local time on Thursday.
Over the next few days, the hot weather is forecast to expand east across the Great Basin, with high temperatures expected to be in the 80s and near 90s.
On Saturday, at least eight Southern California cities broke daily high-temperature marks, including Anaheim and San Diego, which both reached 105 degrees, and Santa Ana, which hit 107 degrees.
Meanwhile, Vista, Calif., north of San Diego, reached a high temperature of 108, breaking a daily temperature record and tying an all-time record high set on June 30, 1985.
Rounds of heavy rain across parts of the Gulf Coast and Southeast
Parts of the Gulf Coast and Southeast are facing more unsettled weather on Sunday, as multiple rounds of heavy rain and thunderstorms move through the area.
A flood watch is in effect on Sunday from parts of Louisiana to Florida and Georgia.
On Sunday, there is a level 2 of 4 risk for excessive rainfall and flash flooding stretching from New Orleans into the Carolinas.
The biggest rainfall totals will occur along portions of the Gulf Coast and the Florida panhandle, from Mobile, Ala., and Biloxi, Miss., to Pensacola and Panama City, Fla. In these areas, 2 to 6 inches of rain is forecast, with localized totals of 8-10 inches possible.
Along the Texas coast, there is a level 3 of 4 "significant" risk of excessive rainfall and flash flooding along the lower Texas coast on Sunday. Rainfall rates of 1 to 2 inches per hour are possible.