(Lincoln, IL) — Heat and humidity will start an upward trend today, with very warm conditions coming for Friday and Saturday. A chance for showers and thunderstorms will be in the forecast for southwestern Illinois into early afternoon today, mainly SW of a line from Springfield to Effingham. A relatively warm night is on tap tonight, with lows in the 70s. The National Weather Service is issuing either a Heat Advisory or Excessive Heat Watch for pretty much the entire state Thursday until Sunday. Temperatures will be in the upper 90s across the state, but the heat and humidity will make it feel like it’s anywhere between 100 and 110 degrees.