The prolonged US heatwave continues to set uncomfortable records

Relentless extreme heat has broken records this summer in the U.S., and experts warn relief could still be some time coming.

Phoenix is at the epicenter of a heat dome that's baking the U.S., shattering countless records this month.

This week in Phoenix temperatures are forecast to remain above 110 degrees Fahrenheit, marking a heat streak going more than three weeks and counting and beating the all-time record set in 1974 by at least one week.

Across the country, the National Oceanic and Atmospheric Administration says, more than 5,000 heat and rainfall records have been broken over a 30-day period.

Like in Las Vegas, which saw 11 days in a row of temperatures 110 or above, smashing its 1961 record.

And El Paso, Texas, which has now endured more than 40 days of 100+ degree temperatures with no relief forecast until Saturday at least.

SEE MORE: Deaths at national parks underscore risk of hiking in extreme heat

Heat-associated deaths have been reported across the nation. Most recently, two women hiking in a Nevada state park were found dead where temperatures reached 114 degrees.

In Arizona's Maricopa County, officials confirm 18 heat-associated deaths since April. Sixty-nine more potential cases remain under investigation.

The National Weather Service doesn't expect relief anytime soon, predicting sizzling temperatures to scorch the Midwest and East Coast later this week.

SEE MORE: How can you save on your water bill amid the heat wave?