Some regions of the southwest saw record-high temperatures on Friday. Readings at the Hollywood Burbank Airport in Los Angeles matched the all-time high when temperatures hit 114 degrees Fahrenheit on Friday, according to the National Weather Service in Oxnard, California.
Downtown Los Angeles also recorded tying its previous high heat record when it logged 111-degree temperatures the same day. Records were set in Santa Anna, Newport Beach, and Ramona when they recorded 113, 95, and 114-degree temperatures, respectively, according to the NWS.
In Phoenix, Sky Harbor International Airport recorded the warmest day of any September with a 93-degree low temperature. That's 12 degrees warmer than the typical temperature for that region during early September.
Yuma, Arizona, recorded a 109-degree day on Friday. The desert town has had a 100-day streak of triple-digit temperatures this summer, NBC News reports.
In Death Valley -- which holds the record for the hottest ground temperature ever recorded on the planet -- temperatures reached 119 degrees on Friday.
Initial heat reports from forecasters showed the heatwave lasting until Friday, but new forecast data suggests some parts of the region will continue to see brutal temperatures through the weekend and potentially into Monday.
Forecasters at NBC News say 50 million people will be affected by heat alerts throughout the weekend.
Those warnings cover areas from Long Beach California to nearly San Luis Obispo County, according to the NWS. Much of Southern California will be under excessive heat warnings until at least Sunday.
"Temperatures should decrease across the West Sunday into Monday as the ridge shifts east over the Central United States, and scattered light showers and storms will be possible as a weak upper-level wave moves across the region," the NWS said in a forecast discussion on Friday.
Southern Californians may finally get to cool off come midweek, according to the NWS. If onshore winds return with cool Pacific air, temperatures may drop to slightly below normal by Wednesday, according to the NWS.
Elsewhere in the country, those living along the Gulf Coast may experience lingering thunderstorms throughout the weekend. Approximately five million people from east Texas to northern Florida have been placed under flood alerts, according to NBC News forecasters.