Big Snowstorm taking aim on the Chicagoland area

The chicago area is bracing for the biggest winter storm in about a month that will begin tomorrow evening and last through the early hours of wednesday morning. A southern stream vort will track out of the central plains that is currently producing some moderate snow to heavy snow in KS/MO/IA out ahead of the southern piece of energy. There was actually just a report of a few places with 1"/hr rates. This southern vort will track eastward before phasing with a very compact intense vort associated with the northern stream as it dives into the midwest from the northwest. You can see both pieces currently on WV.

http://weather.cod.edu/loops/US-WV24.loop.html

First there will be an intial push of WAA snow with the southern wave that will start the snow off tomorrow evening dropping several inches of snow. then the northern vort will continue to dig further south and eventually east, deepening along the way which will create a surface low with the help of the southern stream. this area of low pressure will track from MS northeastward up to southern IN and into OH creating another, more intense band of snow across the area. also, as the storm wraps up to the east we will have winds between 20-30mph which will be more then enough to cause blowing and drifting of the powdery snow.

Here you can see both the southern and northern stream vorts and their positions tomorrow evening.



Here is a closer look at the very intense ULL associated with the northern stream as it begins to head ESE across IA/IL.



6 hours later, its deepening as it heads east, as well as the 700mb and 850mb lows.



This system is going to have a ton of lift associated with it all overlapping up to 500mb, here are the VV maps from 500mb and 700mb.





as the system moves off to the east it deepens and this will create a very nice trowal across the area which will give us most of our snow and possibly heavy snow at that, here you can see the increase in lift at the 700mb and 850mb level





This will create a heavy snow axis from northern IL across lake michigan into portions of southern MI. Here is a image of where the heaviest snow would be tuesday evening and late that night. You can clearly see the heavier snow developing as the sfc low and ULL deepen and lift increases.





Another good advantage for significant snow amounts is the deep DGZ for a long period of time which will allow for maximum snow growth aloft and also in play will be the high snow ratios possibly nearing 20:1 or even higher that will allow the snow to fluff up easily. and to keep going on the advantage train, we will have favorable winds for lake enhancement to take place with good delta T's around 13 which will allow for added moisture into the trowal in northeast IL. here are a few soundings for tuesday morning showing the deep DGZ.





LOT has a Winter Storm Watch out for the area from tomorrow evening through late tuesday night for accumulations of 8-10" with the highest occuring near the lake due to the enhancement. I think we will see some amounts near a foot or even higher where better banding sets up as well as the lake enhancement. The only concern I think is the amount of moisture that gets north but hopefully the very impressive dynamics will help offset that. There is just so much working for this event.

The one thing I really love about this storm is the long duration of it, It should snow for atleast 24 hours, possibly nearing 30 hours. overall im really giddy over this storm and will be a fun one to track.


Matt