Before we get going here I wanted to show you a couple pictures taken around my immediate area. The first was taken on 18th street in Cedar Rapids. You can see the cars that were stranded during the whiteout conditions that developed Tuesday when our 8" of new snow combined with 50 mph winds. It's been a long time since I've seen a picture like this in my area.
This next shot is of HWY 218 in Benton County, Iowa...just west of Cedar Rapids. The highway was impassable and closed for over 24 hours by drifts of up to 10 feet (that height directly from an Iowa DOT snow plow operator). Rotary plows we call elephants had to cut their way through the drifts. A sight to behold and positive proof of what a stretch of winter weather we've been going through. 32" of snow in 32 days here in Cedar Rapids...(1" per day). Dang impressive!
The next snow maker is a disturbance that crosses the central Midwest Saturday night and Sunday. In the animation below you can see energy being ejected out of the mean trough over the Midwest. It eventually gets a closed 500mb circulation that is shown crossing Iowa at 72 hrs (noon Sunday). That provides the lift necessary to generate the snow.
Another feature to keep an eye on is the 850mb circulation which is also shown closing off over far SE Iowa. It's usually about 100-150 miles north of the center that the heavier snows develop. We'll need to keep an eye on that feature in coming days.
Overall, models are in agreement the large scale trough of low pressure becomes inverted as it moves into the Midwest Sunday. Ahead of it, a broad surface low develops over the Plains that rolls across the Mississippi River Valley. The low spreads warm air advection across my area. A series of shortwaves rotating around the developing 850 mb and 500 mb circulations, sets the stage for what should be a long duration period of light to moderate snow.
The GFS & NAM are the strongest model solutions bringing in more moisture and warm air advection while developing the surface low pressure in Missouri. They are also stronger rotating energy around the 500mb low aiding overall lift. In the end this means heavier snows if these models verify, perhaps as much as 5" in some spots.
On the other hand, the EURO is less aggressive with intensity and further south. This leads to lower moisture levels and less snow, especially in the southern half of my area near and south of I-80. However, as I wrote this the latest 0Z EURO just came in and it now looks a bit more robust and similar to the GFS...further south. That consistency is good to see so I'm feeling better about a 3-5" range in much of my area. Tomorrow will be a telling day as we get even closer to the event. OK, here are the latest snowfall forecasts.
The regional perspective of the EURO:
All things considered, it looks like another round of snow is on the way Saturday night and Sunday. Roll weather...TS