The focal point of the blistering heat will fall mostly in Arizona, California, and New Mexico, with peak intensity expected later in the week, according to regional offices of the National Weather Service (NWS).

The forecasts came at the tail end of a week that hit an average global record high temperature, according to the University of Maine's Climate Reanalyzer project.

Arizona

In Phoenix, there have been eight consecutive 110-plus-degree days amid a growing likelihood of temperatures breaking records.

Even though models updated on July 8 are showing slightly cooler temperatures for next week than previous projections did, the current heat wave will probably continue as the high pressure system strengthens into next week, NWS Phoenix said in its latest forecast discussion.

"The atmospheric set up for the latter half of next week also looks to have similarities to the conditions on July 28, 1995 that led to Phoenix reaching 121 degrees and Yuma hit 124 degrees," NWS Phoenix said in an earlier July 7 weather discussion note.

"Even if we do not get quite that hot during this current heat wave, this should go down as one of the longest, if not the longest duration heat wave this area has ever seen," it added.

Excessive heat warnings are currently in effect across south-central Arizona through at least July 16, with an excessive heat watch going into effect on Tuesday and lasting until Sunday as well.

"By next weekend, there is a greater chance for even hotter temperatures," NWS Phoenix said, which will likely cause a further extension of various excessive heat products such as warnings and watches.

"Very hot temperatures will continue through all of next week with the worst of the heat starting the middle of next week. Make sure to practice heat safety when heading outdoors," NWS Phoenix said in a statement on Twitter.