* WHAT...Temperatures up to 100 expected across the mountains and up to 115 degrees along the Rio Grande.
* WHERE...Central Brewster and Lower Brewster Counties, and Chinati Mountains, Chisos Basin, Davis Mountains, Davis Mountains Foothills, Marfa Plateau, and Presidio Valley.
* WHEN...From 1 PM to 9 PM CDT Friday.
* IMPACTS...Hot temperatures may cause heat illnesses. Extreme heat will significantly increase the potential for heat related illnesses, particularly for those working or participating in outdoor activities.