Sunday, February 10, 2013

February 19-22 Potential Winter Storm

Several model runs have been toying with the idea of a potentially major winter storm during the timeframe of February 19-22. Let's dive right in.

We'll start with a recent run of the American GFS model. Here, we see a very strong storm system centered in southern Illinois. The solid blue freezing line is far enough south for the Lower Great Lakes and parts of the Midwest to get snow. If we compare the precipitation forecasts to the legend, we find that cities like Chicago and Quad Cities may get 1.25'' to 1.50'' of water, which would equate to 12-15'' of snow for those areas. This particular forecast is valid the early, early morning hours of February 22nd. For you children wondering if this would cause a snow day, I can tell you right now yes it would. However, we are a long way out, and this solution will likely not happen.

We now move onto a more recent run of the GFS model, now valid for the evening hours of February 22nd. We see there is still a strong storm system in the area, but the system is further north and east than the earlier forecast. Precipitation is much more toned town, but heavy accumulating snow would still be falling in southwest Wisconsin, north Illinois and east Iowa. Those regions would see above 5 inches of snow in many areas, possibly more than 7 inches in the lighter blue. Again, we are a long time away and this will also likely not come to fruition. However, if I had to choose between the above forecast and the image at the very top, this one is more likely to actually happen.

These two images are forecasts from the GFS Ensembles averaged out for mean sea level pressure, 850 millibar temperatures and precipitation. Each image is from a different forecast, not just one model forecast for different times. The images are indeed pretty different, but do print out the same solution: There is potential for a storm in the area around this timeframe. The top image is much drier than the bottom, and the low pressure center is centered in Gary, Indiana. The bottom image holds much more precipitation, and the low pressure center is down on the southern Illinois/southern Iowa border. The presence of ensemble support adds confidence in a situation i'm not that optimistic in to begin with.

This image is of individual GFS Ensemble members from the very top image. If you look closely, you can see that top image in the upper right hand corner of this multi-panel forecast. The other ensemble members do show a winter storm, but to varying degrees of strength. Low pressure placement is also a component that is not resolved. Both issues are expected to occur, as we are still over 300 hours away from this potential event. I will need to see many, many more model and ensemble forecasts that support this idea before I can gain further confidence in this matter.



Anonymous said...

Hi Andrew what happend to the presidents day snow storm starting next friday night sat morning looked like to me east tn would get some snow is that still looking like a good chance or is winter DONE and now the start of spring here in tn? was hoping for atleast 1 more snow event..

Anonymous said...

I really don't like that all these storms (for the most part) look to have snow barely north of us, where they get many inches and we get 1-2 inches of rain, where that could be snow :( :)

Thanks for this forecast (and all others!)!

Anonymous said...

Probably a good idea to change this next update to "High-Imact" Winter Storm. Looking at latest model data, areas from Detoit to Chicago might really get nailed.

Storm-Chaser Wx said...

Well Andrew,you predicted the severe weather event that occurred yesterday, so don't be too hard on yourself, be cause you're pretty good at predicting these types of systems, and I am really hoping for a good last hoorah to winter with this system for the upper Midwest, keep up the great work, a lot of people rely o. You for your forecasts.