CLARKSVILLE, TN (CLARKSVILLE NOW) – Montgomery and surrounding counties are under a Heat Advisory from the National Weather Service today, a heat index expected of up to 109 degrees.

The advisory is in effect from 11 a.m. to 7 p.m.

The high will be in the mid-90s in Clarksville today, with heat index readings of 105 to 109.

Hot temperatures and high humidity could 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 circumstances,” the NWS advisory said.

“Take extra precautions if you work or spend time outside. When possible reschedule strenuous activities to early morning or evening. Know the signs and symptoms of heat exhaustion and heat stroke. Wear lightweight and loose fitting clothing when possible. To reduce risk during outdoor work, the Occupational Safety and Health Administration recommends scheduling frequent rest breaks in shaded or air conditioned environments.

“Anyone overcome by heat should be moved to a cool and shaded location. Heat stroke is an emergency. Call 911.”

Clarksville forecast

Here’s the day-by-day outlook from the NWS.

Today: Mostly sunny. Highs in the mid 90s. West winds up to 10 mph. Heat index readings 105 to 109.

Tonight: Partly cloudy. Lows in the mid 70s. West winds around 5 mph. Heat index readings 98 to 103 early in the evening.

Friday: Partly cloudy with a 30 percent chance of showers and thunderstorms. Highs around 90. North winds 5 to 10 mph. Highest heat index readings around 105 in the afternoon.

Friday night: Partly cloudy. Lows in the mid 60s. Northeast winds up to 5 mph.

Saturday: Partly cloudy. A 20 percent chance of showers and thunderstorms in the afternoon. Highs around 90. Northeast winds up to 5 mph shifting to the northwest around 5 mph in the afternoon.

Saturday night: Partly cloudy with a chance of showers and thunderstorms in the evening, then mostly cloudy with showers likely and chance of thunderstorms after midnight. Lows in the upper 60s. Chance of precipitation 60 percent.

Sunday: Partly sunny. Showers likely and chance of thunderstorms in the morning, then a chance of showers and thunderstorms in the afternoon. Highs in the mid 80s. Chance of precipitation 70 percent.

Sunday night and Monday: Partly cloudy with a 20 percent chance of showers and thunderstorms. Lows in the mid 60s. Highs in the mid 80s.

Monday night through Wednesday: Mostly clear. Lows in the lower 60s. Highs in the upper 80s.