Old Man Winter began to loosen his icy grip Thursday, as temperatures rose throughout northern Utah.
"The air aloft is slowly warming," said Mark Eubank, chief meteorologist for KSL TV and radio.
"Yesterday, when that cold episode happened and the sun was out, there was enough evaporation that a stratus layer — a little, thin layer of clouds — was formed, and that made it warmer last night. It's like a blanket on your bed. It traps any warmth that's there and keeps it from getting super-cold."
Thursday morning's low temperatures were about 10 to 15 degrees warmer than the bone-numbing cold of the previous night. At Salt Lake City International Airport, the low reached 6 degrees at midnight, but then clouds formed and "it did not get any colder," said Jim Nelson, meteorologist at the National Weather Service regional office on North Temple.
Logan's low was minus 5, compared with minus 26 of the previous night. Bountiful's low was 6; Ogden, 5; Provo, 9; Cedar City, 2.
"It's still a little bit below normal," Nelson said. Salt Lake City's normal low for the date is 22 degrees. Highs usually reach 39, but the "hottest" Salt Lake City was likely to get Thursday was in the middle 20s.
A weak weather system is expected Friday night, which should produce snow flurries in the mountains and reduce the temperatures aloft, Nelson said. Beyond that, the only substantial change will be that the temperature will rise a couple of degrees a day for the next couple of days.
Salt Lake City is socked in with an air inversion every morning. The ripple of unstable air might brush it away Friday or Saturday.
Eubank explained that the intense cold was due to a combination of factors: extreme cold temperatures aloft, clear skies, calm winds, and fresh, deep snow.
The thin stratus layer that formed earlier meant that a slight disturbance rolling through the atmosphere on Thursday created ice crystals. These came down as gentle flurries.