BLOG: Strongest "Clipper" of the Season Sunday

It has been a very average Winter so far in the snow department; much of the snow the region has picked up has been by way of "Alberta Clippers", the fast-moving areas of low pressure that originate in western Canada and swing through the Great Lakes region. We have another one of those types of systems coming Sunday, but this will be the strongest one of the season so far.First off: a disclaimer....this remains a somewhat low-confidence forecast. I'll show you why in this Blog. Check the forecast often over the next 36 hours as small changes in the track of the system can result in significant changes to the snow totals.I always think it is interesting to look at how innocuous high-impact systems can look a couple of days before they cruise through. Sunday's storm is just a "blip" in the overall flow of air at 18,000 feet over the eastern Pacific. But this ripple in the flow will become more of a "wave" as it heads over the ridge on the West Coast and dives into the Midwest of the US.By early Sunday afternoon, the system will be over Illinois, with snow spreading east:  I think snow will start off light in the early afternoon, but will pick up in intensity as the storm makes its way into Indiana and southern Ohio in the early evening: The heaviest of the snow will fall in the evening, and then the snow will begin to taper off overnight as the system pushes east: By daybreak Monday, the worst of the storm will be long over, but it can still be snowing lightly and road crews will probably still be in "catch up" mode. The TRACK of the system is going to be very important as it will determine where the heaviest band of snow sets up. A 50-100 mile change can make a big difference. Remember the map I showed at the top, indicating the disturbance that will become our storm is still over the Pacific? Until it gets over land and can be "sampled", the computer models will not have the optimum amount of information about the system "baked into" them. So, we likely will not have a high degree of confidence in the track until tomorrow.Have a look at a few dozen versions of the latest European model (in other words, the "ensemble" version of the model). Sunday afternoon the "L"s are packed pretty close together in Indiana, meaning the model has a decent amount of confidence in the location of the storm at that time: But by evening, the L's are a little more scattered...so the model is less sure where the center of the system will be at that time: Want to be a meteorologist? Figuring this stuff out is FUN, I admit...like piecing together a puzzle. But it is also maddening because we know that the viewers/followers do not like uncertainty and one of the things that we are not great at is COMMUNICATING degrees of uncertainty. One of the hot topics in the field of meteorology is the communication of uncertainty and how we can be better.One way to communicate it is by using percentages. The odds of something happening. That's why I like these maps. Here's the NWS odds of more than 2" of snow with Sunday's storm: Very good odds.   How about 4"? Here ya go: Pretty decent, 40-50% locally. Then the odds go way down for 6":  So, as of Friday morning, I like a general 3-5" storm for the WFMJ viewing area. But again, this is not etched in stone. Check back often. I will have a full update on "Weather For Weather Geeks" this afternoon as well as on 21 News at 6&11. Thanks for reading and have a great weekend!Eric