A heat advisory is in effect through 7 p.m. Monday for St. Louis County and surrounding areas, followed by a severe thunderstorm watch in effect until 10 p.m.

The National Weather Service of St. Louis said that heat index values up to 107 degrees are anticipated.

Everyone in east central Missouri and southwestern Illinois is advised to drink plenty of fluids, stay in air conditioning, stay out of the sun and check on relatives and neighbors. Young children and pets should never be left unattended in vehicles under any circumstances.

Take extra precautions if you are working or spending time outside.

When possible, reschedule activities to early morning or evening, and be aware of the signs and symptoms of heat exhaustion and heatstroke. Schedule frequent breaks in shaded or air-conditioned environments.

Wear lightweight and loose-fitting clothing when possible.

Heatstroke is an emergency that requires a 911 call.

The counties affected by the heat advisory, in Missouri and Illinois, are St. Louis County, St. Louis City, Jefferson, Franklin, Monroe, St. Charles, St. Clair, Clinton, Madison and Washington. The severe thunderstorm watch affects 16 counties in Illinois and 20 counties in Missouri.

People in the St. Louis metropolitan area can get information about cooling centers or energy assistance related to the excessive heat by calling the United Way of Greater Saint Louis at 800-427-4626, or if calling from a land line phone dial 2-1-1. You can also call Cool Down St. Louis at 314-241-7668.