Models show windy, late-autumn storm developing for early next week


The latest Wednesday morning NWS “GFS” model run has arrived and continues developing a huge, windy late autumn storm early next week.

This new GFS forecast has the system on a track northeastward out of the Gulf of Mexico into the Mid-Atlantic states. Such a track would presumably keep its most significant snows well away from Chicago and is far different that the more westerly track last evening’s European model generated.

But here’s the deal—the latest GFS forecast also forecasts it to be such a large system–so large that its cold backside winds will likely blow strongly from the north here in Chicago Monday and Tuesday–something which would have implications for the area’s Lake Michigan shoreline, given the continuation of high lake levels and the prospect this winds could lead to some formidable waves battering the shoreline. And this is just one forecast. Ultimately forecasters will weigh a whole variety of forecasts reconciling model differences.

Questions still linger on any snow prospects from the developing early week system here in Chicago. There’s great anticipation on what the new European Centre model run might show–given the fact last night’s European run projected a rapidly intensifying “bomb cyclone”. THAT forecast had the system deepening explosively from 1012 mb. (29.88″) Sunday evening over the western Gulf to an ear-popping 975 mb. (28.79″) near Detroit, MI by Monday evening.

Is development of such a huge storm merely a one run fluke or does that forecast come anywhere close to holding? Last night’s European forecast track would have HUGE implications for Chicago including powerhouse winds–but also the threat of accumulating snow in the Monday/Tuesday time frame.

Though less intense, the UK Met Office’s overnight model run suggested wind and snow for Chicago as well as did overnight runs of the NWS GFS model.

Wide disparities between model solutions on such systems ARE NOT AT ALL UNCOMMON with big late autumn storms and the forecasts models generate days ahead of these storms’ arrivals.

We will continue to watch and report on forecast developments and will keep you posted.

Those of you who closely follow cold season storm development know how interesting it is to monitor the evolution of the their forecasts. They are incredibly complex systems. The manner in which nature puts these atmospheric behemoths together and the way in which modern models simulate their development in the days leading up to their arrival is never dull.

In order for you to be able to compare model projections for yourself, I’m posting forecast panels from the morning GFS model run AND FROM last night’s fascinating European model run. The comparison is quite stark!


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