The National Weather Service has issued an excessive heat watch in effect from Sunday afternoon through Wednesday evening.  Dangerously hot conditions with heat index values up to 108 degrees are expected for portions of central, east central, and west central Illinois from Sunday afternoon through Wednesday evening.  Xtreme heat and humidity will significantly increase the potential for heat-related illnesses, particularly for those working or participating in outdoor activities. Illinoisans are urged to drink plenty of water, stay in air-conditioned buildings, limit time outdoors, and check up on relatives and neighbors. Continue to monitor the latest forecasts and stick to Regional Radio News for updates.