Moderate

* WHAT...Heat index values up to 108. * WHERE...In Illinois, Madison IL, Monroe IL, and Saint Clair IL Counties. In Missouri, Jefferson MO, Saint Charles MO, Saint Louis City MO, and Saint Louis MO Counties. * WHEN...Until 8 PM CDT Friday. * IMPACTS...Hot temperatures and high humidity may cause heat illnesses. Drink plenty of fluids, stay in an air-conditioned room, stay out of the sun, and check up on relatives and neighbors. Young children and pets should never be left unattended in vehicles under any

* WHAT...Heat index values up to 100-103 degrees. * WHERE...Portions of central and south central Iowa, including the Des Moines metro. * WHEN...Until 7 PM CDT Wednesday. * IMPACTS...Hot temperatures and high humidity may cause heat illnesses. * ADDITIONAL DETAILS...While heat index values may not reach 105 degrees each day, the combination of the longevity of the heat and little or limited relief during the overnight periods with warm lows have prompted the multi-day Heat Advisory.

* WHAT...Visibility one quarter mile or less in dense fog. * WHERE...Central Chippewa, Eastern Mackinac, Southeast Chippewa, Western Chippewa, and Western Mackinac Counties, and Mackinac Island/Bois Blanc Island and Beaver Island and surrounding islands. * WHEN...Until 9 AM EDT this morning. * IMPACTS...Low visibility could make driving conditions hazardous. If driving, slow down, use your low-beam headlights, and leave plenty of distance ahead of you.

* WHAT...Heat index values between 100 and 107 for at least three successive days. Limited nighttime relief as low temperatures are only expected to fall into the low-to-mid 70s. * WHERE...Portions of south central Indiana and north central, northwest, and south central Kentucky. * WHEN...From 1 PM EDT /noon CDT/ this afternoon to 8 PM EDT /7 PM CDT/ Thursday. * IMPACTS...Prolonged hot temperatures and high humidity may cause heat illnesses. Drink plenty of fluids, stay in an air-conditioned room, stay out of

* WHAT...Peak heat index values ranging from the upper 90s to lower 100s Tuesday and Wednesday afternoons. Overnight lows in the low to mid 70s will provide for limited nighttime relief from the heat. * WHERE...Portions of north central, northeast, and northwest Ohio. * WHEN...From 2 PM this afternoon to 8 PM EDT Wednesday. * IMPACTS...Hot temperatures and high humidity may cause heat illnesses. * ADDITIONAL DETAILS...Hot and humid conditions will continue on Thursday, and portions of the Heat Advisory may need to be

* WHAT...Afternoon Heat index values up to 105, only falling into the mid to upper 70s at night. * WHERE...Portions of central, east central, southeast, and west central Illinois. * WHEN...Until 7 PM CDT Thursday. * IMPACTS...Hot temperatures and high humidity may cause heat illnesses. Take extra precautions when outside. Wear lightweight and loose fitting clothing. Try to limit strenuous activities to early morning or evening. Take action when you see symptoms of heat exhaustion and heat stroke.

* WHAT...Afternoon Heat index values up to 105 expected, only falling into the mid to upper 70s at night. * WHERE...Marshall, McLean, Woodford, Champaign, Edgar, and Vermilion Counties. * WHEN...From 1 PM this afternoon to 7 PM CDT Thursday. * IMPACTS...Hot temperatures and high humidity may cause heat illnesses. Take extra precautions when outside. Wear lightweight and loose fitting clothing. Try to limit strenuous activities to early morning

AREAS OF DENSE FOG THIS MORNING... Areas of dense fog this morning are reducing visibilities to 1 mile or less...and in some cases, 1/4 to 1/2 mile or less. This could make driving conditions hazardous this morning. Visibilities are expected to improve with time after sunrise. Leave extra time for travel and slow down on the roads this morning; be alert for school buses. Use low-beam headlights so that others can see you and your taillights.

* WHAT...Heat index values up to 101 expected. * WHERE...Bureau and Putnam Counties. * WHEN...From 1 PM this afternoon to 7 PM CDT Thursday. * IMPACTS...Hot temperatures and high humidity may cause heat illnesses. Drink plenty of fluids, stay in an air-conditioned room, stay out of the sun, and check up on relatives and neighbors. To reduce risk during outdoor work, the Occupational Safety and Health Administration recommends scheduling frequent rest breaks in

* WHAT...Heat index values up to 101. * WHERE...In Illinois, Carroll and Whiteside Counties. In Iowa, Clinton County. * WHEN...Until 7 PM CDT Thursday. * IMPACTS...Hot temperatures and high humidity may cause heat illnesses. Drink plenty of fluids, stay in an air-conditioned room, stay out of the sun, and check up on relatives and neighbors. To reduce risk during outdoor work, the Occupational Safety and Health Administration recommends scheduling frequent rest breaks in