LANCASTER – A heat advisory is in effect for the area until 8 p.m. today. Heat index values of above 100 are expected. The excessive heat can be life threatening for at risk populations, including children, the elderly, and those with pre-existing health conditions. Drink plenty of fluids, stay out of the sun if you can, and stay in air conditioned rooms. Check up on elderly relatives and neighbors and make sure pets have sufficient water and protection from the sun. If you go outside, wear lightweight, light-colored, loose fitting clothes and if you work outside, take frequent breaks. Also, know the signs and symptoms of heat exhaustion and heat stroke.