-- From Times staff reporters Christine Clarridge and Susan Gilmore:

Need an excuse to leave work early Wednesday?

The National Weather Service is warning that the region's heaviest snowfall is expected to roll in after dark, during the evening commute. "I would be really surprised if there's anyplace that doesn't get at least one to two inches," Weather Service forecaster Andy Haner said.

Haner said snow has been falling in pockets around the region over the past 24 hours, with some areas, such as Snohomish and Skagit counties, recording as much as six inches on the ground. In the Seattle metropolitan area, however, people are "waiting for things to happen."

He said heavier snow is expected to begin after sunset.

"I wouldn't call it a 'snowpocalypse,' but it's not going to be a good day to work late," Haner said.

Temperatures in the Seattle area are expected to drop into the 20s late Wednesday, making for slick, icy roads for the evening commute and the possibility of more of the same on Thursday morning.

Although snowfall hasn't yet materialized in Seattle, the Seattle Department of Transportation (SDOT) sent 10 snowplows into North Seattle and eight plows in South Seattle. SDOT is now in a full 24-hour response plan to keep roads open and buses moving. The response plan calls for sending out 30 trucks with plows, which will be placed throughout the city in key locations such as bridges and trouble spots.

The department starting pre-treating major roadways with salt brine Tuesday afternoon.

As the morning commute wound down Wednesday morning, the state Department of Transportation [DOT] said there were no major problems in the Seattle area.

"We dodged a bullet this morning," said DOT spokeswoman Meghan Pembroke. She said traffic on roadways seemed lighter than normal, perhaps because commuters were frightened away by the snow prediction. "People are taking it slow, and that's good," she said.

Seattle and state officials, hoping to avoid the mistakes of the past when snow closed roads and shut down some services for days, have prepared preparing for the worst. In Seattle, roads have already been treated with an anti-icing agent and snow plows are lined up and ready to go, according to city officials.

King County Metro Transit will not pull its articulated buses from the roads in the event of snow, according spokeswoman Linda Thielke. During the last major Seattle snowstorm in November, many of the articulated buses got bogged down on streets.

"They make up half our fleet," Thielke said of the articulated buses.

During peak morning hours, she said, Metro has 1,030 buses on the road. Of those, 520 are articulated buses and they provide 30,000 of the 50,000 available seats.

Thielke said that Metro's articulated trolleys — the ones normally used on the city's steepest slopes — have already been pulled from service and will be replaced throughout the storm with smaller trolleys and buses.

Theilke said that every bus and vehicle will be chained by Wednesday afternoon.

Metro Transit urged riders to sign up for rider alerts and get to know the snow routes. Metro Transit will send riders alerts to their phones or e-mail accounts to warn them of schedule alerts.

People may sign up for alerts at http://metro.kingcounty.gov/signup/.

Sound Transit also advised its riders to sign up for alerts at its website, soundtransit.org. The agency suggested riders bundle up to prepare for longer waits in case of weather-related delays.

Riders should allow extra time to reach their destinations and meet their buses at stops also used on snow routes, even if the weather doesn't seem too bad, a Metro Transit news release suggested.