Phoenix about to shatter yet another heat record for big cities: "Intense and unrelenting"

Phoenix's relentless streak of dangerously hot days was poised to smash a record for major U.S. cities on Tuesday, the 19th straight day the desert city was to see temperatures soar to 110 degrees Fahrenheit or more.

Nighttime has offered little relief from the brutal temperatures. Phoenix's low of 95 degrees on Monday was its highest overnight low ever, topping the previous record of 93 degrees set in 2009. It was the eighth straight day of temperatures not falling below 90, another record.

It's "pretty miserable when you don't have any recovery overnight," said National Weather Service meteorologist Matt Salerno.