At about 9 a.m. I talked with Cheryl Sharpe of the National Weather Service, Norman Forecast Office for a look back at the weather system responsible for the latest mix of winter weather:
“Basically it was kind of an ordinary upper level storm system that was mixed with an artic air mass that came out of Canada before it got here. So, under normal circumstances it would have just been an ordinary rain and thunderstorm event with maybe some marginally severe weather, hail that kind of thing.
“But what happened was instead we had a really cold atmosphere close to the ground and up above the artic air we still had remnants of the warm air that had been here the day before.
“It undercut that and lifted it up basically. So we had snow falling into the really warm layer, melting and falling into the cold layer and freezing and turning to sleet in most places. Farther north it wasn’t quite as warm aloft and they got snow.
“When it first started the cold air at the surface wasn’t thick enough, so the rain that fell through the cold layer didn’t have a chance to freeze. It hit the ground and then it froze. So that’s why we had the ice on the ground first and then the sleet.”