...EXTREME HEAT WARNING IN EFFECT FROM 11 AM SUNDAY TO 8 PM EDT WEDNESDAY FOR THE LOWER SUSQUEHANNA VALLEY... * WHAT...Dangerously hot conditions with heat index values over 105 expected for the Lower Susquehanna Valley. * WHERE...Adams, Cumberland, Dauphin, Franklin, Lancaster, Lebanon, Perry, and York Counties. * WHEN...From 11 AM Sunday to 8 PM EDT Wednesday. * IMPACTS...Heat related illnesses increase significantly during extreme heat and high humidity events. * ADDITIONAL DETAILS...Heat index values and the associated risk of heat-related impacts will be highest on Monday and Tuesday. PRECAUTIONARY/PREPAREDNESS ACTIONS... Drink plenty of fluids, stay out of the sun, and stay in an air-conditioned room. Check up on relatives and neighbors, and provide pets with adequate water and shelter from the sun. Extreme Heat can be life-threatening among at-risk populations, such as children, the elderly, and those with pre-existing health conditions. In addition to the daytime heat, overnight low temperatures will also be very warm and oppressively muggy. &&