Spring arrives at 12:30 a.m. Sunday, and it's likely to do a pratfall atop a snow cover.

Forecasters say the region should see snow, anywhere from 1 to 4 inches, but computer models still were having a hard time resolving differences late Friday.

The precipitation cold begin in the southern Delmarva as early as Saturday afternoon, perhaps as rain, said Lance Franck at the National Weather Service in Mount Holly.  In the immediate Philadelphia area, snow could begin late Saturday night.

Most of what falls across the region will be snow, and could continue into early Sunday evening, although anything that falls during the day Sunday is going to have a hard time sticking on roads and sidewalks, because it has been so warm.

Franck said the heaviest amounts, in the range of 2 to 4 inches, would be likeliest just to the north and west of I-95.

Precipitation amounts will drop farther north and west of the city, said Dan Pydynowski, a meteorologist with Accu-Weather Inc. Any mixing would hold down totals south and east.

There is a threat of minor coastal flooding Sunday, the weather service said. Other threats include wind gusts of 25 to 35 mph, and wet, heavy snow that sticks to trees and power lines.

The system is slated to bring snow or rain to the bulk of the Mid-Atlantic and Northeast this weekend, with the potential for blizzard conditions in New England.

Here's a day-by-day breakdown of what to expect, from NBC10's Sheena Parveen:

Saturday: Mostly sunny, partly cloudy. Highs around 47 degrees.

Saturday night: Lows around freezing with the storm approaching.

Sunday: We could see snow by the morning, certainly by noon. The timing may change, though, as we get closer. it will be cold enough for all snow north and west, mix to snow in Philadelphia, then rain to snow or a mix in New Jersey and Delaware. Accumulations will be higher north and west, maybe a few inches or more (as of now), with less as you go farther south and east because of higher rain chances and a mix. But if the timing changes, then that would directly affect snow totals. So this will have to be watched very closely. Snow should melt at the start, but then as temperatures drop below freezing later Sunday night, snow will stick to roads. Expect more of a "wet" snow with higher water content.

Sunday night: Snow continuing, with a better chance for any precipitation to change to snow in New Jersey and Delaware. It should be tapering off overnight as of now. Temperatures are expected to be below freezing overnight.

Monday morning: There will be icy spots on roads; some streets could still be snow-covered from Sunday night. Depending on the timing of the storm, some snow could still be falling early Monday morning.