* WHAT. Heat index values up to 109. * WHERE. Portions of north central, northeast, and south central Texas. * WHEN. Until 8 PM CDT Thursday. * IMPACTS. Hot temperatures and high humidity will increase the risk for heat-related illnesses to occur, particularly for those working or participating in outdoor activities.

* WHAT. Heat index values up to 109. * WHERE. Portions of North and Central Texas * WHEN. Until 8 PM CDT this evening. * IMPACTS. Hot temperatures and high humidity will increase the risk for heat-related illnesses to occur, particularly for those working or participating in outdoor activities.

The combination of warm temperatures and humid conditions will produce afternoon heat index values of 103 to 107 degrees. A few locations could briefly experience heat index up to 110 degrees. Those spending extended time outdoors could be susceptible to heat related illness if not taking proper heat precautions, such as drinking plenty of water and taking frequent breaks out of the sun and heat. Young children and pets should never be left unattended in vehicles.