WFAA-TV

All of North Texas is under a National Weather Service Heat Advisory through Monday evening; Dallas, Tarrant, Denton, Collin and the other counties in the center of the map not highlighted in orange are under an Excessive Heat Warning.

Saturday's high hit 107, and North Texans were sweltering through another day of record-breaking heat on Sunday.

"It is going to be a scorcher out there," said WFAA-TV meteorologist Nancy Snell. "Our heat index values [will be] close to 110."

Snell forecasted that the high temperature at Dallas/Fort Worth International Airport will reach 107 degrees on Sunday afternoon, which tops the record of 105.

The National Weather Service reported that the D/FW temperature hit 105 at 3 p.m. Sunday, and the mercury was in the triple-digits at all other major North Texas weather stations except Mesquite, where a 99-degree reading was measured.

The National Weather Service issued a Heat Advisory for all of North Texas until 7 p.m. Monday.

In addition, an Excessive Heat Warning is in efffect through the same period for Dallas, Tarrant, Denton, Collin, Rockwall, Kaufman, Grayson, Fannin, Lamar, Hunt, Delta, Hopkins, Van Zandt and Rains counties. The warning signals a prolonged period of dangerously hot temperatures.

The weather service said highs between 103 and 107 degrees coupled with moderate humidity levels will make it feel like it's 110. The agency suggests that anyone taking part in outdoor activities take frequent breaks and drink plenty of water. Wear loose-fitting, light-colored clothing.

Check on the elderly and people with health problems, because they are the most likely to suffer from heat exhaustion and heat stroke, the weather service said. Don't leave children or pets in a vehicle, even for a short period of time.

"Triple-digit heat continues Tuesday under mostly sunny skies," Snell said, "then we'll be a little less hot Wednesday through Saturday ... highs in the upper 90s."

North Texas hit its 22nd day of triple-digit temperatures on Friday. Friday and Saturday temperatures topped out at a blistering 104.

The Texas Forest Service, meanwhile, warned that the intense heat and lack of moisture are a recipe for outdoor disaster

"It doesn't take much for a wildfire to ignite," said Mark Stanford, fire operations chief for the Forest Service.

"In this drought condition, fires will happen. It is up to people to practice caution and to be aware of how their everyday actions can accidentally start a fire."

WFAA.com staff and Dallas Morning News staff writers Michael E. Young and Dan X. McGraw contributed to this report.