It’s already been a record-shattering weekend, weather-wise, in much of Iowa.

“How quickly we went from a rather wintry April to a very summer-like May,” Cory Martin of the National Weather Service office in Johnston, said early Sunday evening.

Heat advisories were issued for central and northwest Iowa on Sunday.

“It’s just a strong ridge of high pressure that’s right now pretty much parked over the central tier of the country and that’s brought some unseasonably hot conditions,” Martin said, “a pretty early season heat wave.”

Several locations in Iowa reported record highs on Sunday. The temperature reached 97 in Davenport, Ottumwa and Waterloo. It was 98 in Mason City. Fort Dodge and Des Moines reached 99 degrees. Carroll and Spencer reached the 100 degree mark. Sioux City was the hottest spot — topping out at 101 degrees.

“Definitely an unusual heat event to see this early in the season,” Martin said.

It may be a degree or two cooler today, but the temperatures are likely to still reach into record high territory, according to Martin.

“Through the middle of the week, looks like temperatures are going to fall back a little bit. We’re looking at highs Wednesday maybe in the mid-to-upper 80s,” Martin said. “That’s still a few degrees above normal for this time of year, but as we get back into Thursday and Friday, it looks like we’re going to warm right back up into the 90s and then we’ll be watching another system coming our way this weekend which may bring us some relief, but that’s still a little ways out, so it’s kind of tough to tell what to expect out of that at the moment.”

Temperatures in Iowa are unusually in the mid-to-upper 70s this time of year. With all the heat and humidity in Iowa right now, Martin said there’s plenty of instability in the atmosphere right now to fuel some thunderstorms.

“The issue, if you’re looking at tornadoes right now, is the jet stream is pushed well north of the area,” Martin said. “We don’t have any stronger winds aloft that would typically help us with storm organization, to really get some significant severe weather going.”