* WHAT...For the Extreme Heat Warning, dangerously hot conditions with heat index values up to 109. For the Heat Advisory, heat index values up to 102 expected. * WHERE...Portions of central, north central, southwest, and west central Nebraska. * WHEN...For the Extreme Heat Warning, until 7 AM CDT Monday. For the Heat Advisory, from 7 AM to 10 PM CDT Monday. * IMPACTS...Heat related illnesses increase significantly during extreme heat and high humidity events. 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. Do not leave young children and pets in unattended vehicles. Car interiors will reach lethal temperatures in a matter of minutes. Stay cool, stay hydrated, stay informed. Monitor the latest forecasts and warnings for updates. 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.