That's when the season's first freeze could hit the valleys.
A snow advisory was to be in effect until noon, the National Weather Service in Salt Lake City reported this morning. Mountain resorts reported five or six inches of snow accumulation by late this morning, with the snow still falling.
They are "big flakes, and there are lots of low clouds," said Alta Lodge hotelier Marcus Dippo. "Clearly, early to mid-September is a reasonable time for a first snow. This is that beautiful time of year when the fall colors are happening, with the snow on the vegetation poking through."
Weather Service forecaster Pete Wilensky said Alta saw around six inches at mid-mountain. A Weather Service camera shows about 5 inches on a picnic table on the deck of Snowbasin's Needles Lodge.
(see for yourself: http://www.wrh.noaa.gov/slc/camera/mosaic/was_mtn.php" Target="_BLANK">http://www.wrh.noaa.gov/slc/camera/mosaic/was_mtn.php)
"It will be snow-squally on and off through the day," Wilensky said.
Overnight temps are expected to dip into the 30s across most of the state's northern and central valleys, which could put sensitive plants in the danger zone. "If you're in Herriman or Riverton, parts of Utah Valley, you could see a nip of frost," he said, adding frosts are expected in Cache County, Delta and Cedar City.
But since the overnight low at Salt Lake City International Airport is expected to reach 39 degrees, Salt Lake City gardeners could avoid the hit.
Tomorrow it will still be cool, Wilensky said, but Wednesday and Thursday should be "gorgeous" fall days.
"We might still see 80-degree days again before winter sets in," he said.
That could happen this weekend as south winds preceding a weak cold front arrives on the Wasatch Front, Wilensky said.