Metro Atlanta awakened Tuesday to record-breaking cold – the coldest temperatures in a generation – and while the mercury is expected to stay below freezing through Wednesday afternoon, a late-week warm-up will push temperatures into the 60s by Saturday, forecasters said.

Clayton County police were trying to determine whether a man’s death overnight near Jonesboro was weather related.

A police spokesman told Channel 2 Action News that the 66-year-old man’s body was found behind a group home before midnight, as the mercury plunged through the low teens toward overnight lows in the single digits.

Readings at 7 a.m. Tuesday included 4 degrees in Alpharetta, Dallas and Dunwoody, 5 in Chamblee, Marietta and Cartersville and 6 at Hartsfield-Jackson International Airport.

Atlanta’s old record for Jan. 7 was 10 degrees, set in 1970.

A brisk northwesterly breeze pushed the wind chill as low as 14 below zero.

In the mountains, the actual air temperature at 6 a.m. was -2 in Blue Ridge and -1 in Blairsville.

A wind chill warning was in effect until 1 p.m. for Cherokee and Bartow counties northward for dangerous wind chill as low as -25. The rest of metro Atlanta — and as far south as Americus and Cordele — was under a wind chill advisory through 1 p.m.

But Channel 2 meteorologist Karen Minton said that after only climbing into the mid-20s Tuesday afternoon and falling back into the mid-teens Tuesday night, temperatures will reach the low 40s Wednesday afternoon and continue to climb daily through Saturday, when highs should top out in the low 60s.

Minton is calling for dry conditions the rest of the work week, with highs in the mid-40s Thursday and low 50s Friday and morning lows in the upper 20s Thursday, upper 30s Friday and upper 40s Saturday.

The next chance of rain will be on Saturday, according to Minton.

School systems throughout metro Atlanta and the rest of north Georgia shut down Tuesday in anticipation of the Arctic blast and homeless shelters were packed overnight.

The Arctic temperatures not only brought more people into shelters overnight, but the cold also kept them there during the day. The Atlanta Mission and the Salvation Army have extended their hours, opening earlier and closing later, since the morning temps were expected to be just as brutal as the overnight conditions.

Central Night Shelter, which operates out of Central Presbyterian and the Catholic Shrine of the Immaculate Conception, is staying open through Wednesday morning, its director said.

“There was a roar of applause last night when I told the men they didn’t have to go in the morning,” said Katie Bashor, who is the director of the ministry. “We will stay open until 8 a.m. Wednesday, which is also later than usual because the men are generally gone around 6 a.m.”

Bashor said both locations took in a few more men than usual Monday night because it was the right thing to do.

“We’ve got the greatest volunteers in Atlanta who are making sure we’ve got enough food and snacks to keep everything going,” she said.

In Cobb County, firefighters battling a house fire in Kennesaw late Monday night had to run hoses an extra long distance after finding the closest hydrants frozen.

The state Department of Transportation reported scattered areas of black ice on metro roadways during Tuesday’s morning commute, including an icy patch after 6 a.m. in the right lane of I-285 eastbound at Ashford Dunwoody Road.

The DOT reported ice in the two center lanes of I-285 northbound before South Cobb Drive just before 7 a.m.

In Marietta, water from burst pipes turned part of busy Powder Springs Street into an icy mess during Tuesday’s morning commute.

Marietta police spokesman David Baldwin said the incident occurred at an old and abandoned apartment complex near Gramling Street.

“What appears to have happened is that the pipes in one of the abandoned buildings have all frozen up and burst,” Baldwin told The Atlanta Journal-Constitution.

“The water has poured down a long driveway and into the roadway, causing a real severe hazard,” he said.

“There’s probably at least an inch or so of ice on the roadway,” Baldwin said shortly after 9 a.m. as a fire truck blocked the icy right lane of Powder Springs Street.

“Emergency crews are on the scene, but there’s not a whole lot they can do until the water is cut off,” he said. “One of our police officers spotted it initially and was able to preempt a dangerous situation.”

MARTA spokesman Lyle Harris warned that MARTA trains would be running slower than normal Tuesday morning “in the interest of safety.”

Several hundred riders waited in the cold for 30 minutes at the North Springs station for trains that normally run every 15 minutes.

“Trains will resume running at normal speeds once temperatures rise to 10 degrees or higher,” Harris said, adding that some bus routes could also experience weather-related delays.

Georgia Power crews were working after 9 a.m. to restore service to some 9,450 customers who were without electricity. Another 200 customers of the state’s electrical membership cooperatives were also without power early Tuesday.

Staff photographer John Spink and reporter Michelle Shaw contributed to this article.