* WHAT. A prolonged period of hot conditions with heat index values around 100 degrees. * WHERE. Portions of east central and southeast Indiana, northeast and northern Kentucky, and central, south central, southwest, and west central Ohio. * WHEN. Until 8 PM EDT Saturday. * IMPACTS. Hot temperatures and high humidity may cause heat illnesses.

* WHAT. Heat index values in the upper 90s to around 100 degrees. * WHERE. Portions of east central and southeast Indiana, northeast and northern Kentucky, and central, south central, southwest, and west central Ohio. * WHEN. Until 8 PM EDT this evening. * IMPACTS. Hot temperatures may cause heat illnesses.

The Miami Valley Regional Planning Commission and the Regional Air Pollution Control Agency have issued an Air Quality Alert for Montgomery, Miami, Greene, Clark, Preble and Darke counties in the Miami Valley Region, until midnight EDT tonight. Levels of ozone within the region may approach or exceed unhealthy standards. On Alert days, help reduce ozone by taking the following actions: * Carpool, if possible, bike, walk or take the bus instead of driving alone. * Refuel your vehicle after 8 pm. * Do not idle your vehicle, exhaust contributes to air pollution. * Mow your lawn in the evening hours and avoid the use of gas-powered lawn equipment. For additional actions and information, visit miamivalleyair.org or call 937-223-6323

The Indiana Department of Environmental Management has declared an Air Action Day, until midnight EDT tonight. Levels of ozone within the region may approach or exceed unhealthy standards. On Alert days, help reduce ozone by taking the following actions: * Carpool, if possible, bike, walk or take the bus instead of driving alone. * Refuel your vehicle after 8 pm. * Do not idle your vehicle, exhaust contributes to air pollution. * Mow your lawn in the evening hours and avoid the use of gas-powered lawn equipment. For additional actions and information, please visit the IDEM Smog page at: https://www.apps.idem.in.gov/smogwatch.

The Miami Valley Regional Planning Commission and the Regional Air Pollution Control Agency have issued an Air Quality Alert for Montgomery, Miami, Greene, Clark, Preble and Darke counties in the Miami Valley Region, until midnight EDT Saturday night. Levels of ozone within the region may approach or exceed unhealthy standards. On Alert days, help reduce ozone by taking the following actions: * Carpool, if possible, bike, walk or take the bus instead of driving alone. * Refuel your vehicle after 8 pm. * Do not idle your vehicle, exhaust contributes to air pollution. * Mow your lawn in the evening hours and avoid the use of gas-powered lawn equipment. For additional actions and information, visit miamivalleyair.org or call 937-223-6323

* WHAT. Peak heat index values of 95 to 100 through Saturday. * WHERE. Portions of northern Indiana and southwest Michigan. * WHEN. Until 8 PM EDT /7 PM CDT/ Saturday. * IMPACTS. Hot temperatures and high humidity may cause heat illnesses to occur. * ADDITIONAL DETAILS. Heat stress increases with the number of consecutive hot days. The effects of heat are most impactful for more vulnerable urban populations.

* WHAT. Dangerously hot conditions with peak heat index values of 95 to 102 through Saturday. Low temperatures in the 70s at night will provide little relief from the heat. * WHERE. Portions of northern Indiana and northwest Ohio. * WHEN. Until 8 PM EDT Saturday. * IMPACTS. Extreme heat and humidity will significantly increase the potential for heat related illnesses, particularly for those working or participating in outdoor activities. * ADDITIONAL DETAILS. Heat stress increases with the number of consecutive hot days. The effects of heat are most impactful for more vulnerable urban populations.

An extended period of hot and humid conditions will continue across all of Central Indiana through the weekend. Daily high temperatures in the 90s with heat indices approaching 100 degrees may be hazardous for sensitive and vulnerable populations. Take extra precautions if spending time outside during peak heating of the day.

An extended period of hot and humid conditions will continue across all of Central Indiana through the weekend. Daily high temperatures in the 90s with heat indices approaching 100 degrees may be hazardous for sensitive and vulnerable populations. Take extra precautions if spending time outside during peak heating of the day.