* WHAT. Heat index values up to 109 expected. * WHERE. Portions of central, northern, northwest, southwest, and western Oklahoma and northern Texas. * WHEN. From 11 AM this morning to 9 PM CDT this evening. * IMPACTS. Hot temperatures and high humidity may cause heat illnesses.

* WHAT. Dangerously hot conditions with heat index values of 110 to 115 degrees expected. * WHERE. Portions of central, east central, northern, southeast, and southern Oklahoma. * WHEN. From 11 AM this morning to 9 PM CDT this evening. * IMPACTS. Heat related illnesses increase significantly during extreme heat and high humidity events.

* WHAT. Dangerously hot conditions with heat index values up to 115 expected. * WHERE. In Oklahoma, Canadian, Grady, Kingfisher, Garfield, and Grant Counties. In Texas, Archer and Clay Counties. * WHEN. For the first Excessive Heat Warning, until 9 PM CDT this evening. For the second Excessive Heat Warning, from 11 AM to 9 PM CDT Saturday. * IMPACTS. Heat related illnesses increase significantly during extreme heat and high humidity events.

* WHAT. For the first Heat Advisory, heat index values up to 108. For the second Heat Advisory, heat index values up to 107 expected. * WHERE. Portions of northwest, southwest, and western Oklahoma and northern Texas. * WHEN. For the first Heat Advisory, until 9 PM CDT this evening. For the second Heat Advisory, from 11 AM to 9 PM CDT Saturday. * IMPACTS. Hot temperatures and high humidity may cause heat illnesses.

* WHAT. Dangerously hot conditions with heat index values of 110 to 115 degrees expected. * WHERE. Portions of central, east central, northern, southeast, and southern Oklahoma. * WHEN. For the first Excessive Heat Warning, until 9 PM CDT this evening. For the second Excessive Heat Warning, from 11 AM to 9 PM CDT Saturday. * IMPACTS. Heat related illnesses increase significantly during extreme heat and high humidity events.

* WHAT. For the Heat Advisory, heat index values up to 109. For the Excessive Heat Warning, dangerously hot conditions with heat index values up to 110 expected. * WHERE. In Oklahoma, Caddo, Comanche, and Cotton Counties. In Texas, Wichita County. * WHEN. For the Heat Advisory, until 9 PM CDT this evening. For the Excessive Heat Warning, from 11 AM to 9 PM CDT Saturday. * IMPACTS. Heat related illnesses increase significantly during extreme heat and high humidity events.