After looking over this morning's 12Z model runs, it appears that snow is not going to be a big issue here on Saturday. Unfortunately, like we talked about yesterday, freezing precipitation will be more of a player, at least through Midday here in the Metro.

The WRF had begun to look more & more like the GFS over the past 24 hours, so that indicates that when we were looking at the GFS in yesterday's blog, we were on the right track. We will stick with the GFS as the model de jour in our look out into the 48 to 54 hour time range from now.

 12Z 11/29/07 GFS surface/1000-500 mb 48 hour forecast - valid 6 AM Saturday

Note here that we have a thickness of around 5520 meters over Omaha. This indicates warmer air aloft that is allowing snowflakes to melt into water droplets, which then will fall to the ground & hit <32° surfaces = freezing rain.

 12Z 11/29/07 GFS 700 mb 48 hour forecast - valid 6 AM Saturday

On this map, green indicates the Relative Humidity at 700 mb (~10,000') and the thin red line circling Omaha shows upward vertical velocity. You want to lift moist air to make precipitation.

 12Z 11/29/07 GFS surface/1000-500 mb 54 hour forecast - valid Noon Sat.

The thickness is up to 5580 by Noon, indicating a continued warming of the layer & the heaviest precip has moved into central Iowa, back up towards Sioux City.

 12Z 11/29/07 GFS 700 mb 54 hour forecast - valid Noon Saturday

I've outlined the greatest area of lift in yellow for you. It's off to the north & east of Omaha, coinciding with the heavier snow/freezing area on the surface map above this one.

I don't see a very long period that will be good for snow making in the Metro. Before 6 AM, we could see an inch or so, but that's just a first guess. The main focus will be the freezing rain in the 6 AM to 10 AM time period. As warmer air moves in, the ZR should switch over to a period of cold rain before ending. So Saturday Morning will be the messiest time of anyone driving around. Most of the lift heads out when the warmer air arrives, so any cold PM rain should be fairly light.

Here's what our in house computer model shows for 6:45 Saturday Morning.

"Official" amounts forecasts will be entered Friday, but I would look for 1-3" of snow from TQE to DNS to CIN, and in the 2-4" range for up near Sioux City. At least that's my view at this moment.

Bottom line: stay indoors & watch it out your window if you can Saturday Morning. By afternoon, travel shouldn't be too bad across most of the area south of Highway 30. I would suspect the streets department will be out sanding/salting early Saturday as this storm isn't really going to surprise too many in the loop.

I'll check in tomorrow.

Jeff