Odds are good this week's heat will break Twin Cities records

As hot as this summer has been, the Twin Cities has not hit any record-high temperatures — but that's likely to change this week.

A hot and humid air mass is expected to park over Minnesota for the next three days, pushing the mercury into the upper 90s with heat indexes — what it feels like with humidity added in — soaring to as high as 111 degrees.

An excessive heat warning goes into effect for the Twin Cities and the southern third of Minnesota at 11 a.m. Tuesday and runs through 10 p.m. Wednesday. A heat advisory will be in effect from Wednesday night through 7 p.m. Thursday as overnight temperatures remain in the 70s, the National Weather Service said.

The best chance at setting a high temperature record will be Wednesday, when the forecast calls for 99 degrees at Minneapolis-St. Paul International Airport, National Weather Service meteorologist Eric Ahasic said. The warmest Aug. 23 since weather records have been kept was 97 degrees in 1948.

Record or not, "this is some serious heat," Ahasic said — the kind of weather that sends people to lakes and pools to cool off, if they are open.

Some metro area aquatic centers closed for the season on Sunday. In Edina, there are not enough lifeguards to keep the city's pool open as many begin returning to college or start participating in high school sports. The same is true in Bloomington, Crystal and New Hope, which have also closed their pools for the season. A free splash pad in Crystal's Becker Park remains open.

In Minneapolis, the Parks and Recreation Board on Monday began reduced hours at water parks, pools and beaches. Lifeguards will be on duty from 4 to 7 p.m. weekdays and 1 to 7 p.m. weekends through Labor Day, according to a post on the parks department's website.

The late summer blast of heat will add to the 24 days thermometers have reached 90 degrees or higher this year. That is well above the average of 13 days, but well short of the 44 days above 90 degrees set in 1988.

"If 90 degrees is a home run, then we've hit a lot over the fence, but not that far over the fence," said Kenny Blumenfeld, a senior climatologist with the Minnesota Department of Natural Resources.

"We have not had any Harmon Killebrew 500-foot home runs," he added, in a nod to the former Minnesota Twins player who smacked 573 round-trippers during his career.

"Hitting 100 would make this heat wave look a bit different," Blumenfeld said.

The Twin Cities has not seen a 100-degree day in August since 1988. And there have been only seven days of 100 degrees or hotter ever in the month of August, according to the state Climatology Office.