HIGH IMPACT WINTER STORM...

Currently an extremely energetic weather pattern is unfolding that promises to bring high impact weather to the Midwest into early next week. Two areas of significant snow are expected. The first wave Saturday night and Sunday impacts Minnesota as well as central and northern Wisconsin. Snowfall totals of up to a foot (locally more) are possible in that event.

A second wave of energy associated with a deepening trough develops a surface low in SE Iowa that tracks towards Chicago, creating another round of potentially heavy snow that impacts my area Sunday night and Monday. Winds up to 55mph are shown on the GFS, which combined with falling snow have a chance to produce whiteouts and blizzard conditions somewhere in the region.

In advance of the the late weekend event, a powerful clipper has induced an intense pressure gradient that has produced straight line wind of 60 to 70 mph in my northern counties today. Anamosa reports the strongest speed with a gust of 69 mph. The Dubuque Airport clocked in with a gust of 66.

This is all part of a long wave pattern loaded with energy. Today's wind maker is passing, setting the stage for the two additional short waves to do thier damage this weekend. The swirl in the Pacific is set to buckle the jet forming a potent trough and closed upper air low that lifts NW Sunday.

This is the negatively tilted 500mb trough shown Sunday night over SE Iowa on the GFS

In this animation you can watch as the energy comes off the Pacific and digs into the Plains before curling northeast into the Great Lakes, creating the powerful late winter storm scenario.

The system is in the evolutionary stages which means data is still being processed into the models. Some changes are to be expected, normal in a storm of this magnitude. What does appear evident is the 2 phased element of the event. The first passing north of my area, the second much more in play locally Sunday night.

The issue to watch now is the placement of the deepening surface low Sunday evening. Notice the GFS at 7:00pm has the surface low placed near Kewanee.

The EURO is closer to Rockford.

It may not seem like much, but hat 100 mile spread makes a big difference in snowfall accumulations. The GFS being further south is a much snowier solution for Iowa, it also allows more wind. Here's what the operational models of the GFS and EURO show for snow totals. This is just raw model guidance. Far from a forecast yet.

The GFS

The EURO

The snow locally all comes Sunday night. While it will be wet initially, transitioning from rain to snow, temperatures crash into the 20s and at 10:00pm Sunday the GFS is showing wind gusts NW of the low pressure of 50-55 mph. With at least several inches of snow shown, that could lead to blizzard conditions and whitouts Sunday night and early Monday. My NW counties are most favored for that potential.

The NWS has Winter Storm Watch's in effect from the Quad Cities north into Minnesota and Wisconsin. The watch in my counites is for Sunday night and Monday.

Based on further data regarding track and intensity, counties could be added or deleted. Minor changes in track could make significant differences in overall impacts. A shift NW (a possibility) means less in the way of snow , further southeast (not likely), means more. Lots more to come on this event. Roll weather...TS

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