UPDATED at 5 p.m. with temperature reaching 108.
The temperature reached 108 degrees today, and you'd have to be at least 58 years old to say you've endured worse in St. Louis.
The high-pressure system that has been burning up Colorado and Kansas is pushing its center through the two-state area today. With soil moisture and humidity already low, the forecast is for a withering jump in temperatures today and Friday.
"The air will heat up in a hurry, like it does in a desert," said Wes Browning of the National Weather Service office in Weldon Spring.
Good analogy, and an ominous one.
Because rainfall already is 5 inches below normal for May and June, conditions are likely to worsen in the coming weeks.
Browning, meteorologist in charge at the local Weather Service office, said the core of high pressure will weaken temporarily after it passes through. But the basic system will prevail, keeping the high temperatures at 108 Friday and at or above 100 degrees through July 4. No break is in sight.
Last year, the temperature didn't reach 100 until July 11. And St. Louis hasn't recorded five consecutive days at or above 100 since 1983.
Local governments have posted heat advisories, prepared cooling centers and urged residents to check on elderly relatives and neighbors.
Summer fun, meanwhile, is being adjusted. In Farmington, Mo., 60 miles south of St. Louis, the city canceled its Fourth of July fireworks show because of dry conditions that already have fed grass fires. Heat also was a factor.
"We felt like it's absolutely irresponsible to have a fireworks display on a large scale with these weather conditions," said city administrator Greg Beavers.
At Quail Creek Golf Club in south St. Louis County, pro shop attendant Charlie Beck said calls for tee times have fallen and some golfers had canceled their rounds. In Highland, Laura Wilken, the aquatics supervisor, said many swimmers abandoned the outdoor pool for the indoor water park on Wednesday, when the temperature hit 98.
"They'll be swimming indoors," she said.
In Webster Groves and many other places, the show will go on. Webster's Community Days begins Sunday, when the high is forecast at 102. Fireworks will be on Wednesday.
"It's full steam ahead," said Mike Oppermann, the Webster parks director.
Edwardsville is urging residents to use water sparingly. In St. Louis, where the water works draws from the Mississippi and Missouri rivers, water use is up about 20 percent since May 1, said water commissioner Curtis Skouby.
Daily use is about 150 million gallons daily, he said, half the system's capacity.
"We still have plenty of water," he said.
The record high for today's date is 104, set in 1952. It hasn't been 108 degrees or worse here since July 18, 1954, when the temperature was 112 degrees. The hottest ever on record in St. Louis was 115 degrees, set four days before, on July 14, 1954.
The temperature hit 107 on one day each in 1984 and 1980, the latter during a crippling heat wave that killed 153 people. All told, it was 100 degrees or hotter on 18 days in 1980.
Last summer, there were 15 such days, and 19 people died of heat-related stress.
Browning, of the Weather Service, said the high-pressure system controlling the Central Plains now is similar to the one that burned up Texas last summer, and which fed the series of hot spells in the St. Louis area.
Pat Guinan, a Missouri state climatologist, said the prevailing dry pattern is a bad sign. Historically, he said, a dry May-June period often is followed by more drought and heat.
"Soil moisture here is pretty much nonexistent already," Guinan said. "We're entering the time in summer when widespread precipitation is unlikely. It's safe to say things will only get worse."
Terry Hillig and Leah Thorsen of the Post-Dispatch contributed to this report.