THE BACK END OF THE BEAST..
A powerful winter storm continues to swirl over the upper Midwest. It's brought heavy precipitation, both rain and snow to many parts of the central U.S. This is a Doppler radar estimate of how much liquid equivalent has fallen since the onset of the storm. That's a lot of water, especially for January.
Most of the precipitation from central Iowa southeast has been rain. However, from Nebraska and far NW Iowa into Minnesota and northwest Wisconsin snow totals continue to mount. Here's reports through Wednesday evening with snow continuing to fall in spots.
Amounts of 1-2 feet are common from NE Nebraska to SE South Dakota and central Minnesota.
Most of Minneapolis and St. Paul have had 10-15 inches with the storm winding down.
Here's a picture sent to me of snow out of Sioux Falls, South Dakota (just NW off the NW tip of Iowa.
We are now on the back end of the beast who's center of upper air energy can be seen on this satellite image drifting into NC Iowa Wednesday night. Vorticity wrapping around the closed 500mb circulation has kicked up snow showers around my area. These are going to continue in the region much of the day Thursday. There is some hint at saturation in the dendritic zone which may lead to some periods of snow heavy enough to create accumulations up to an inch. It's hard to define where the bands may form but the favored region is the northern half of my area, especially I-80 north.
Here's what models are suggesting for snow totals through Thursday.
The EURO
The GFS
The 3k NAM
The system finally departs the area Thursday night and at some point clouds should break leading to at least some pockets of sunshine under a weak ridge Friday. Highs both Thursday and Friday should range from the low 30s north to the mid 30s south.
Saturday and Sunday has some question marks as models struggle to resolve phasing issues. With a split in the upper air pattern it seems unlikely that a merger would take place that would bring significant precipitation far enough north to impact my area. Most models agree with that assessment showing the brunt of the wave energy just south of my area. That may bring some clouds but only a slight chance of snow or a mix to my southern counties. The EURO leads the way showing a dry weekend.
The GFS is the rogue man out showing phasing and enough amplification to close off a 500mb low over southern Iowa. This allows for greater surface development further north. It's also a wetter solution that produces several inches of snow in Iowa on across much of my area, especially the northern 2/3rds. Travel would be impacted. I just don't see any real support for such a solution. The large scale consensus is heavily against the GFS and I suspect it will back off in the end leaving my area high and dry. At least that's my gut feeling. Here's the difference in snowfall between the benign EURO and the robust GFS.
The EURO
The GFS
With or without any snow, it appears temperatures Saturday and Sunday will be near to slightly above normal for early January meaning highs in the low to mid 30s.
Last but not least, I continue to see a consistent trend in modeling to run the MJO (Madden Julien Oscillation) into phases 8, 1, and 2 the last half of January. Follow the purple lines whose dots reflect the dates. We haven't entered 8 yet and may not for another 6 days. Here's a sampling of some key MJO forecasts.
The EURO
The CFSv2 climate model
The GFSv12 extended outlook
The consistency is exceptional. The reason I care is at this time of year those phases are the holy grail of cold. You can see the temperature analogs for 8, 1, and 2 in January below.
Not only that, the GFS extended shows the AO (Arctic Oscillation), EPO (Eastern Pacific Oscillation) and NAO (North Atlantic Oscillation, all generally negative.
The AO