What We Know As of Now

Iowa Snowfall GFS Forecast

Well hopefully by now, you have heard of the potential for a major winter storm early next week. If you haven’t, you clearly have been removed from all forms of technology, and human interaction, as there hasn’t been anyone NOT talking about it. It seems it has become the chatter around the watering hole. So what is this fuss all about? There is the potential for a strong storm system to impact the upper Midwest from Tuesday into Wednesday. If you have travel plans on these days, you will want to keep a close eye on the weather and have a plan B ready.

cmc_snow_acc_iowa_32

The three main models that we are currently watching are the GEM (Canadian), GFS (American) and the ECMWF (European). All three long range models have been pretty consistent with the strength and track of this storm system. As you will notice comparing the image at the top of this article, which is the new 18z GFS and the image right above this paragraph, which is the 12z GEM, they are very similar. The track fluctuates northwest to southeast from run-to-run, but only a hundred miles or so. There have been no major flip-flops the past few days, so this leads to increase confidence, which explains for all of the chatter. However, the storm system is still out in the Pacific ocean, so that leaves room for error, which is why some are holding off on snowfall totals graphics.

As of timing, things could change as we go into the weekend, but as of now, it appears snow will begin to fall across the state very early Tuesday morning. Snow will continue to fall throughout the day on Tuesday, and the potential for heavy snowfall rates will also exist. The system will then begin to pull out of the state on Wednesday, but strong winds will continue to be an issue. The strong winds will also be an issue on Tuesday, which will produce blizzard like conditions. Forecasted wind gusts as of now are expected to be over 40mph, and will continue to increase as the low deepens as it tracks off to the northeast.

Snowfall totals do appear to be in the moderate to heavy category at this time. The heaviest snowfall accumulations should fall in the range of 6″ to 12″, with the potential for locally higher amounts. Once again, this is subject to change depending on the strength of the storm. We are still five days away, so all you can do right now, is to continue checking back for the latest updates.

Zach Sharpe

My name is Zach Sharpe. I am the president and forecaster for the Iowa Storm Chasing Network. You can find me on Twitter @Stormchaserzach and on Facebook at: https://www.facebook.com/stormchaserzach/

(9) Comments

  1. Zach,

    What I am confused about is that all of you weather forecasters use the same models and pretty much have all the same equipment,yet all have different forecasts. How can this be? You say the models are all consistent with one another, but NOAA says the models don’t agree.

    • Zach Sharpe

      Tony, the answer to your question is in your question! As you said, we have all these different models, but you have to use human knowledge to narrow it down to one forecast. You can’t go on TV or in a blog, and tell people here is this model, this model, and this model, so pick the one you like and go with it. We have to make a forecast. Typically more than 5 days out, forecasters will downplay an event and will increase there forecast as confidence increases. This explains why forecasts are all different. Now as to NOAA saying the models don’t agree, I haven’t seen that in any National Weather Service forecast discussion yet. I have seen the opposite. A lot of NWS forecasting offices are shocked at how consistent and in agreement the models are with one another so far out. That is unheard of! The track will continue to sway northwest and southeast as this system is still developing, which will impact snowfall totals. This is the main thing that we are still watching as we get closer to Tuesday.

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