We’ve enjoyed a mild spring in Washington, with just touches of heat here and there. But starting Sunday and persisting well into next week, we expect the most intense and longest-lasting heat wave of the year so far.

Computer models agree: High temperatures in the low to mid-90s are likely from Sunday to Wednesday, maybe even a little higher at times.

Tuesday may turn out to be the hottest day, with mid-90s possible. Some models are projecting a high of up to 97 degrees, which would break Washington’s record of 96 from 1954 on that date.

Rising humidity levels will only make it feel hotter.

At the onset of the heat wave on Sunday, humidity levels may be tolerable. But especially by Tuesday and Wednesday, they will become more oppressive, producing likely heat index values between 95 and 100, at least.

The National Weather Service projects that there is an 80 percent chance that the heat index reaches at least 95 on Tuesday and a 36 percent chance that it exceeds 100.

The predicted weather pattern is a textbook example of the kind supporting a heat wave in the Mid-Atlantic. An area of high pressure is forecast to develop off Bermuda, which will pump hot, humid air from the south into the region.

By late in the week, the high-pressure cell will move far enough away from the Mid-Atlantic for the heat wave to fade, but the pattern is still predicted to be a warm one — with highs in the 80s.

Enjoy the 70-degree days this week. They may be the last for a long time.