Updated 12/24/09 7pm:

The first round of snow and a bit of wintry mixed precipitation is down, which left anywhere from 1-4" of snow in the area, along with some sleet and freezing drizzle.  So what else is in the works?  Well the main area of low pressure will churn to the north from Arkansas through Missouri and Iowa into Christmas Day.  The easterly flow will continue and once again the farther south you are, the more likely freezing rain or rain will be more common than that of snow and sleet.  Although not getting as much snow may seem good, it really is the opposite as a half inch or more of ice accumulation making driving dangerous since you can't get traction, let alone that ice weighing down power lines and tree branches.  With that said, colder air should push back into the region on Christmas Night causing any mixed precip to go back over to periods of light to moderate snow.  What was slushy will turn to solid ice, so if you are shoveling, take care of it before too late in the day on Christmas.  Here's the breakdown of what you can expect with the remainder of this storm.

Thursday Night:  A mixed bag of sleet, freezing rain and some snow continues, becoming moderate to heavy at times after midnight.  From Wausau and roughly Highway 29 on north & west, snow mixed with sleet and freezing rain will fall.  Additional snowfall of 2-4" with up to a quarter inch of ice. The most snow will be found to the northwest of Wausau.  To the south, rain, freezing rain and some sleet will dominate with the potential for an icy accumulation of up to one inch of ice.  Travel will be very slippery and hazardous.

Christmas Day:  Periods of sleet, freezing rain and a bit of snow from Wausau on north & west continues into the early afternoon, while rain, freezing rain, and some sleet persists to the south.  A slushy additional 1-3" of snow for the northern half of the area and a quarter inch of ice, with a quarter to half inch of ice accumulation to the south along with the rain.  Colder air is anticipated to start pulling in toward evening, but likely that will be after the precipitation has tapered down to snow showers or light mix.

Christmas Night into Saturday: Temperatures will slide back through the 20s and off/on light to moderate snow is likely.  A few inches of accumulation is possible in the area.

In the end, the worst of the storm will be to our west into western Wisconsin, Minnesota, northwest Iowa, and the eastern Dakotas.  One to two feet of snow will pound the Twin Cities and likely make air travel out of there very difficult.  Farther south and east, odds are better for a mix/rain to fall, which could cause delays at airports, but not shut them down.