Relief from this week’s extreme heat is expected to arrive on Thursday. National Weather Service meteorologist Jeff Johnson says high temperatures will switch from the triple digits to more seasonable highs in the mid-to-upper 80s.

“It’s going to seem like jacket weather almost…and all we’re really going to do is knock the temperatures back down to normal,” Johnson said. Prior to Thursday, many areas of the state could post four consecutive days with temperatures climbing above 100.

A cold front should begin to push the heat out of the state Wednesday evening. “Equally or even more important to that is we have a decent chance of thunderstorm development along that frontal boundary as it moves southeast Wednesday afternoon and evening,” Johnson said.

“It’s going to be a little bit hit and miss, like it has been all year, but we do have a decent chance of seeing some thunderstorms. Those fortunate people who get those, as long as it’s not severe, may be looking at a half-inch of rain in spots.” This has been one of the driest, hottest summers in Iowa history.

Des Moines, for example, has received just 3.61 inches of rain since May 7. Johnson said it hasn’t been this dry in Iowa since 1894. Johnson notes July 2012 could close as the second hottest month ever, second only to July of 1936.

“In 1936, though, we had 15 days in a row of above 100. Obviously, we’re not going to touch that,” Johnson said. Although the cold front will bring cooler temperatures and the possibility of rain later this week, another wave of high heat is forecast for next week.