As an unrelenting heat wave enters its 39th consecutive day, millions of people from California to Florida are asking: When will it end?

The long-term forecast looks bleak. For most, the extreme heat will continue for the foreseeable future, with no end in sight for the rest of the month, but there is a brief glimmer of hope for some parts of the country headed into the weekend.

An area from South Texas to Arizona to South Florida has had the worst of it and that will only continue. El Paso, Texas, has been in the triple digits for 32 consecutive days. In Miami, the record warm sea surface temperatures, combined with light winds are causing stifling heat: The heat index there topped 100 degrees or more for a record 37 consecutive days. Phoenix will break the record of 18 consecutive days at or above 110 degrees today and the streak will likely continue for at least another week or more.

That longevity combined with the dangerously low overnight temperatures in the 90s are taking a toll on human health and infrastructure there. There have been 12 confirmed heat-related deaths in Phoenix in the first week of July, and 55 heat-related deaths overall so far this year, according to data from the Maricopa County Department of Public Health.

"The heat is taking a major toll," Frank LoVecchio, an emergency room doctor at Valleywise Health Medical Center in Phoenix, told CNN. "The hospital has not been this busy with overflow since a few peaks in the COVID pandemic."

Heat is the number one killer of all extreme weather, National Weather Service data shows, and as temperatures continue to rise, scientists expect it to make even more people ill.

Historic heat dome to shift later this week

An enormous, relentless stubborn ridge of high pressure has trapped air inside in a "heat dome" resulting in extreme temperatures as the dome parks itself over areas.

The heat will remain until a shift in the weather pattern occurs and either breaks apart the heat dome or moves it out of the country completely. That's not expected anytime soon.

Instead, the dangerous heat will continue through this week, with more records broken each day. More than 1,500 heat records have already been broken this month and another 75-plus could fall by the end of the weekend.

The Desert Southwest and Texas will continue to see daytime highs in the triple digits this week. High temperatures along the Gulf Coast and mid-South will be in the upper 90s for the rest of the week, with heat indices as high as 115 degrees. Record-breaking warm low temperatures will provide little relief in what's typically the coolest time of the day.

Only the Southern Plains and Gulf Coast could see some relief in the coming days as the heat dome shifts back to the west and a cold front advances across the area. By the end of the week, numerous cities will at least temporarily get out of the most intense heat.

Little Rock, Arkansas, will go from a high of 101 today to a high of 87 on Friday. Oklahoma City will also go from triple digits today to the mid-80s on Friday.

No end in sight for hardest-hit areas

The heat streak will continue headed into August in the Desert Southwest and South Florida.

The only hope for the Southwest is that sporadic monsoonal rain will bring some temporary relief, however, the overall temperature pattern will remain hot. Areas that do see any rain could see higher heat indices because of additional moisture and higher humidity coming in from Mexico.

According to the Climate Prediction Center, temperatures in much of the South, including South Florida, and the Southwest will remain above normal, meaning the next two weeks should continue to be hot.

If that holds true, then the heat wave will be approaching two consecutive months, or more than 50 days, over these same areas.