Then the cold comes roaring back.
The temperature Monday night is expected to fall to single digits, with wind chills as low as 10 degrees below zero after midnight.
Cold continues Tuesday, when the mercury will sit around 10 degrees. With the wind, Bunker said, it could feel like 15 degrees below zero.
By Wednesday, the temperature starts to warm up slightly, with sunny conditions and the mercury in the mid-20s. Warming will continue into Thursday, with highs in the upper 30s, Bunker said. Precipitation is possible Thursday into Friday.
The frigid blast follows a snowstorm that dropped nine inches on the city, according to National Weather Service readings at Philadelphia International Airport.
With the snow came cold, and records were set and tied throughout the region.
Philadelphia's low Saturday was 8 degrees, not quite hitting the record of 2 degrees set in 1918.
Allentown tied the record low of minus 4 degrees set in 1981. In Reading, the low of 1 degree was bitter cold but not a record-breaker; the mercury fell to minus 5 there in 1981.
Atlantic City set a record of minus 3, breaking the record of zero set in 1918. Trenton tied its record, also set in 1918: minus 1 degree.
As recovery continued Saturday, Philadelphia International Airport reported all four runways had been cleared. Only one runway had been open Friday.
Flight delays persisted, due largely to a series of canceled flights the day before and weather issues in the rest of the country, airport spokeswoman Victoria Lupica said.
Philadelphia Streets Department vehicles continued to rumble through the city, making a second pass on 2,200 miles of roads.
"The bulk of the work is done. We need less plowing at this point," Streets Department Commissioner David J. Perri said Saturday.
By the end of the weekend, Perri estimated, the Streets Department will have used 10,000 tons of salt.
Across the river, crews were struggling in Camden County to clear roads.
"The weather being the way it is with the temperature, it's tough," County Freeholder Ian K. Leonard said Saturday. "Because yesterday we had sunlight, but by the time we were able to deal with what we had, the temperatures kept plummeting."
Streets were 80 percent to 85 percent clear down to pavement, Leonard said.
About 25 to 30 workers would continue to salt the roads, he said, aiming to have them clear by the end of the weekend.
Regional Rail trains were plagued by delays averaging 10 to 15 minutes Saturday because of the weather, SEPTA spokesman Manny Smith said. SEPTA expected no major service interruptions or cancellations, Smith said, with buses and subways running on normal Sunday schedules.
But the Regional Rail delays could persist, Smith said, because of "additional operational difficulties" caused by the cold.
Smith also warned transit riders against chasing a ride down:
"This is not the weekend . . . for you to run for a train or a bus," Smith said. "Use extra caution."
Bunker also offered some precautions, advising people to "open their cupboards below their sinks to allow adequate heat to keep things warm down there, and maybe even run a trickle of water to make sure that their pipes don't freeze up."
"And with these cold temperatures, make sure they have at least a half a tank of gas in their car to make sure that they don't run the risk of freezing up their fuel lines."