Dangerous early season extreme heat is on tap for parts of Texas this week in a prelude to what’s expected to be an abnormally hot summer nationwide.

Sweltering heat more commonly seen in the throes of summer than in the spring was making an unwelcome visit this week to a large portion of the U.S. – from the Dakotas to Texas and other parts of the South – prompting forecasters to tell residents to be cautious when being outside.

The main power system for the state of Texas is bracing for a surge in electricity demand as a heat wave is forecast to drive up temperatures across the middle of the state to above 100 degrees Fahrenheit (37.