Snow: Inches tonight, foot this weekend?

Tonight's snowfall could be puny compared to what might start the weekend.

"Some place is going to get a foot or more [starting Friday], but I can't say if it's going to be Virginia or Pennsylvania," said meteorologist Anthony Gigi of the National Weather Service in Mount Holly.

The system moving in this afternoon could leave an inch or two by morning. The timing looks good for commuters, since the flakes should start after rush hour today, and be tapering off by sunup tomorrow, Gigi said.

No complications are expected from wind, sleet or freezing rain, he said.

The snowfall should be fairly uniform across the Philadelphia region, with maybe a little more toward the Shore, he said. A high in the 40s tomorrow should help clear sidewalks and highways.

Overall, it's a weaker system than the one that dropped a few inches on parts of South Jersey and Delaware on Saturday.

Friday's threat, though, could wind up reminding people of the Dec. 19 storm that dropped more than 20 inches of light snow in Philadelphia, he said.

But maybe not.

It's too soon to predict how much any area will get.

"You can't. It really depends upon the track," he said.

But the potential exists for lots of digging out on Saturday.

"Any time you get something out of the Gulf of Mexico you have to think in essence of one-foot snows," because such systems carry so much moisture, he said.

The weather could be windy, but not extremely so.

When the snow might start is also iffy. It could start Friday morning, but the official forecast calls for a 30 percent chance of rain and snow in the afternoon, becoming all snow overnight.

"The closer you get to an event, the more accurate the forecast is," Gigi said.

As to whether big storms seem to hit on weekends, the science isn't clear, Gigi said. Most of Washington, D.C.'s 10 biggest storms hit on weekends, but add in more events and the effect seems to go away.

No one has put forth a sound explanation either - though theories exist, such as West Coast pollution adding condensation nuclei for East Coast precipitation, he said.

For more on the forecast, go to http://go.philly.com/weather.