The temperature could hit the triple digits in the Tri-Cities for the first time this year on Monday.
The National Weather Service is forecasting a high of 99 for Sunday and 101 on Monday.
Normal highs for late June in the Tri-Cities are about 85 degrees, according to the weather service.
The coming heat wave should be a short one. By Tuesday the high could be back in the high 80s in the Tri-Cities.