Tracking the next system: Could this be the one for snow?

An interesting change occurred with Monday evening's model runs in regards to the next weather system forecast for the end of this week.  The cold front is still forecast to move through Wednesday night and will be just to our east as the sun rises Thursday morning.  The one thing that has changed is the track the of the upper level low.  Earlier this week the upper level low was to our north essentially keeping the bulk of precipitation through the Upper Midwest because that's where the main forcing, or uplift, with this storm was going to be.  When I was putting the forecast together this morning, the general upper level storm track had shifted south and was crossing more over Iowa and Illinois while a deepening low pressure system was forecast to develop in Michigan.  This type of track would favor a fair amount of lift within our atmosphere to generate advisory level snow.  Now, before you go digging out the snow blowers or shovels there are a couple important factors we need to look at for the Wednesday night/Thursday morning time frame.

The current low in the south will keep a lot of the gulf moisture from making much progress northward, however, it will be pulling in a little moisture from the Pacific.  Secondly, the main storm itself is now just starting to show in the northwest so as expected, the weather models have been doing some flip-flopping.  If this trend continues for today and Wednesday morning then you'll want to find your snow shovels.  On the other hand, the amount of lift generated in the upper levels will be able to squeeze out whatever moisture we do have late Wednesday and into Thursday.  Another important factor to look at in determining if/how much snow will fall is the atmospheric profile along with snow to liquid ratios.  Snow to liquid ratios will probably be high due to the lack of moisture so this would produce more of a fluffy snow which would accumulate more than a heavier, wet snow.  Also, the dendritic zone (layer in the atmosphere where temperatures are roughly -12°C to -18°C for a certain distance) may be large enough to efficiently produce snow.  When you typically have a deep dendritic zone your totals can be higher. 

We'll continue with updates here, facebook and twitter so be sure to keep checking back.  Should a snowfall forecast be needed the First Warn Weather Team will update it on the blog Wednesday.  This is to ensure we have the most up-to-date information for you.