The regional weather service office for Houston and Galveston typically issues an extreme heat warning when heat index values reach or exceed 113 degrees or an actual air temperature of at least 105 degrees is expected.
Under such excessive humidity and extreme heat, forecasters said, the public health risk for heat-related illnesses increases significantly. The weather service recommends that the public practice these heat safety measures:
The warning area includes a large portion of Texas, stretching from Waco, south to Galveston, then down to Palacios. Counties included in the extreme heat warning are Harris, Montgomery, Fort Bend, Wharton, Brazoria, Matagorda, Galveston, Liberty, Colorado, Jackson and Waller.
Some communities within the warning area include Houston, Conroe, Sealy, The Woodlands, Baytown, Galveston, Bryan, College Station, Crockett, Sugar Land and Freeport.
Compounding the extreme heat, the Texas Commission on Environmental Quality is also warning Houston residents of high concentrations of ground-level ozone on Wednesday.
An Ozone Action Day is in effect Wednesday for the Houston, Galveston and the Brazoria areas. Air quality may be unhealthy for sensitive groups with respiratory issues such as asthma.
Ground-level ozone is a pollutant often created by a mix of sunlight, heat and industrial emissions, particularly from gasoline-powered engines. The TCEQ recommends avoiding the use of gas engines to help reduce ozone pollution.
The public is encouraged to carpool, walk, ride a bicycle, take your lunch to work to avoid driving, and avoid drive-through lanes to keep your engine from idling and releasing emissions.