DALLAS >> Wintry weather is forecast for much of the U.S. today, with freezing temperatures expected to dip as snow falls as far south as Texas’ Gulf Coast.

“Typically, we just don’t have quite this much cold air in place that far south,” said Marc Chenard, a meteorologist with the National Weather Service’s Weather Prediction Center.

The storm has prompted officials in Houston, where temperatures were in the 70s Fahrenheit earlier this week, to advise residents to prepare for power outages and hazardous roads that could be similar to those experienced in the wake of a Category 5 hurricane. Temperatures were expected to drop to below freezing there by tonight.

He said significant ice and up to 12 inches of snow were expected across parts of the southern Plains today and into Monday, with the most snowfall expected near the Oklahoma-Texas border.

Winter weather conditions are affecting large portions of the U.S., but it is rare for them to extend so far south, Chenard said.

The Dallas area had a covering of snow by Sunday morning, with flakes still falling, and as much as 6 inches was forecast.

Chenard said sleet and freezing rain could hit further south.

“We’re looking at potentially over a quarter inch of freezing rain, and that will cause significant impact,” Chenard said. “We may even see some freezing rain get as far as New Orleans by early Monday.”

Texas Gov. Greg Abbott, who issued a disaster declaration for all of the state’s 254 counties, warned on Saturday: “All of Texas is facing an extremely dangerous winter storm.”

Abbott, Oklahoma Gov. Kevin Stitt and Arkansas Gov. Asa Hutchinson have each activated National Guard units to assist state agencies, such as rescuing stranded drivers.