With more than 59 million people under various heat warnings Saturday, the hot weather was expected to simmer unabated for the next few days.

The sweltering weekend conditions impacted cities including Los Angeles, Seattle and Las Vegas in the West, and in Raleigh, North Carolina, Washington, D.C., and New York City in the East.

“A staunch upper ridge” has brought a “widespread and long duration heat wave” to the West, where temperature records may be tied or broken over the weekend,…