Update: Snowstorm may not hit until midnight

Posted: Dec. 18, 2008 12:16 p.m.

The good news is you have a little more time to run your errands tonight.

The National Weather Service has bumped back its winter storm warning from 9 p.m. to midnight.

The not-so-good news: Once the storm hits, it's expected to be fast and furious, dropping two inches or more per hour of snow until it reaches the predicted 7 to 11 inches.

Oh, and did we mention the threat for thundersnow?

It usually happens only once a year and not every year, but meteorologist Penny Zabel said the chances for loud bangs during your overnight slumber are highly possible.

Sweet dreams.

"It's pretty rare," she said. "There's just enough upward motion in the atmosphere with some forcing that's given it enough lift to produce some convection."

In simple terms, please?

"Basically it's a thunderstorm with colder air that keeps it snow instead of rain," Zabel said.

Snow is expected to be consistent through the night with the heaviest coming before 6 a.m., according to Zabel.

Snow is expected to slow by noon Friday, but there are a few possibilities of light snow showers into the afternoon, Zabel said. The winter storm warning is still in effect through 3 p.m. Friday.

"It's a system that's bringing significant weather to a stretch of the country from Las Vegas all the way through Kansas, Missouri, Iowa, Illinois, Wisconsin and up into Michigan," Zabel said.