It'll be hot, but July heat waves are becoming more common

The heat is on in the Twin Cities and much of Minnesota, where thermometers flirted with 100 degrees Monday — a streak that's expected to continue through the rest of the month.

A brief respite is expected Wednesday when highs will drop into the upper 80s, but a heat dome parked over the central United States will push temperatures back into the 90s Thursday and continue through the weekend, the National Weather Service says.

The blistering heat and humidity is not unusual for Minnesota in July and is becoming quite common. The average daily temperature for the month has risen from 73.8 degrees to 74.3 degrees over the past 20 years.

Since 2000, the Twin Cities metro has seen only five Julys with a temperature below the daily average of 74.3 degrees. Over the past 22 years, the normal high for July has been 84, while the normal low has been 66, the Minnesota Climatology Office said.

"We are definitely beating those," said Pete Boulay of the climatology office. "We are seeing warmer Julys." .

A heat advisory took effect at noon Monday for the Twin Cities and south-central Minnesota, and will stay in place through 6 p.m. Tuesday. The temperature combined with the humidity will at times make it feel as warm as 102 degrees, the Weather Service said.

In western Minnesota, a heat advisory was expected to be in effect until 8 p.m. Monday, the agency said. Appleton in western Minnesota was the state's hotspot at 2 p.m. when the temperature hit 97.

This week's heat burst is exacerbated by a lack of rainfall. Just 0.88 inches of rain has fallen in the metro since July 1, allowing the air and ground to heat faster and hotter.

As temperatures stay high, rainfall totals will remain low and won't help moisture-starved lawns and farm fields. A cool front dropping in from the north Tuesday could set off some showers, but sunny conditions will prevail the rest of the week, the Weather Service said.

The rain deficit has pushed a swath of Minnesota from the east metro to Mankato into the moderate drought category, the U.S. Drought Monitor said. Areas from Redwood Falls to St. Cloud and the northwest metro were labeled as "abnormally dry," the Drought Monitor reported Thursday.

The Twin Cities metro was expected to hit a high of 98 degrees Monday with heat indexes — what it feels like — topping 100. Alexandria, Redwood Falls and St. Cloud reached heat indexes of 101 degrees. It felt even hotter in Hutchinson, Willmar and Fergus Falls at 102, while heat indexes hit 103 in Madison and 104 in Fargo and Grand Forks, N.D., the Weather Service said.

But it's the low temperatures, which may not fall below 70, that compound the issue, Boulay said.

On Monday, Hennepin and Ramsey counties opened buildings and recreation centers to offer free places to linger in climate-controlled comfort. The Salvation Army service centers in the Twin Cities also opened their doors as cooling centers, and libraries, movie theaters and shopping malls offered additional relief.

As oppressive as it felt, Monday was far below the hottest July day on record — that came in 1936, when the temperature hit 108 in the Twin Cities. The all-time high anywhere in Minnesota was 115 on July 29, 1917 in tiny Beardsley, the state Department of Natural Resources said.

The current heat wave "doesn't look too bad compared to that," Boulay said. "It's not a string of 100s."

Still, plenty of heat is in store over the next two weeks, the Climate Prediction Center said. It forecasts above-normal temperatures — meaning more 90-degree readings — at the end of July.

When the hot spell breaks, it may be the end of this year's long-running stifling conditions.