By Kate Bilo

PHILADELPHIA (CBS) - Today was certainly the calm before the storm – lots of sunshine and blue skies, but it was COLD outside! If you look on Live Mega Doppler 3 this evening, you can see a relatively fast-moving shield of snow pushing through the Midwest and headed our direction.

The fact that the storm is arriving overnight is a big factor for us, because temperatures at the onset will mainly be in the upper 20′s, and we’re following a spell of several cold days. That means the precipitation will start as snow for everyone, and it’s cold enough that it will stick to the roads.

The snow should start around 2 a.m. and as we head toward sunrise, we’re going to start to see the warmer air and the mixing begin. The changeover will happen first in South Jersey and Delaware – many folks will wake up to a driving rain.

In the city, around 7 or 8 a.m., I expect a wintry mix to begin, leading to very hazardous travel conditions. We could see this sleet, freezing rain and rain mixture continue right through the noon hour, so expect roads to be slick and icy through at least early afternoon.

In the Lehigh Valley and the Poconos, we expect 3-6″ with the higher accumulations farther north (some of the mountaintops could pick up as much as 8″). A Winter Storm Warning will be in effect for those areas.

In the city, we expect 1-3″ of snow followed by a slushy mix, and south of the city about a coating to a slushy inch before the changeover to rain. The snow map that we first released yesterday at 6 p.m. still looks accurate for tomorrow’s event.

So while this isn’t the biggest snowstorm we’ve ever seen, the nasty combination of snow, sleet, ice and rain will lead to a miserable start to the weekend for anyone that has to travel.