Good morning everyone! Looking over the model data this morning, things still continue to be somewhat indecisive on the track of the storm. Last night if you tuned into our live question and answer session, the GFS and ECMWF were in agreement with one another. The GEM was off its rocker, as it had all of the heavy snow missing Iowa. We said we assumed the GEM would correct itself overnight, and that’s exactly what it did!
The Weather Prediction Center has outlined the area they think has the greatest potential for heavy snow, as pictured above. The area that currently has the greatest potential for the highest snowfall amounts will be the ones outlined in the red. The further outside of the red outlined area, the lower the snowfall amounts will go. So what exactly are the models showing?
Starting off with the GEM, it has corrected itself to what it had been showing in previous model runs. It has the heaviest snow falling across southwest Iowa to northeast Iowa. This includes areas like Creston, Des Moines, Ames, Ft. Dodge, Waterloo, Cedar Rapids and Dubuque.
The GFS is slightly more to the northwest than the GEM. It is a little more to the north than what I believe that it should. I will explain why here in a second when I show the NAM. The one similarity it has to the GEM is the snowfall accumulations, which range from 8″ to 15″. By this afternoon we should begin to get a better idea of what we are looking at for snowfall accumulations.
Lastly, the NAM goes out just far enough now to show the track it is taking. It is further to the south than the GFS, but looks to be closer to the GEM. That is why at this point, I believe the 12z GFS is too far to the north. The NAM is also slower, which would delay the snowfall to early Tuesday morning, instead of late Monday evening.
Once again, we would like to stress that a lot of you are wanting to know “how much will I see?” but due to the differences in the track and timing, it is still early to tell. Once some of the higher resolution models begin to pick up on this storm, that will help increase the forecast confidence. Stay tuned throughout today and this weekend as we will continue to update you on the very latest. You can follow me on Twitter @StormChaserZach or at @IAStormChasing.