Why Are We Going to Get So Much Snow?

This storm could go down in the record books. If the storm slows anymore and we end up receiving the amounts that are on the high end of our forecasted spectrum. IF that were to happen, and I stress IF, then we could be making history. Everyone keeps talking about how dangerous this storm is, and its going to dump tremendous amounts of snow, and have ridiculous winds, and its going to........etc. I'm sure everyone gets sick and tired of hearing that, the general over exaggeration of an approaching storm. But what exactly makes this storm different? Why is THIS storm going to bring us all that snow and not all the other ones that have passed through. Well, the answer is quite complicated but I will make it as easy as possible.

The major ingredients for a big snow event are heat (a relative term of course), moisture, lift, and a long duration. Well heat this time of year is definitely relative. But the heat source for storms this time of the year either comes from the sub tropical jet stream (the river of air way up in the atmosphere that carries a lot of heat and moisture) and the sun, for obvious reasons. We have that, u will just have to take my word for it.

Moisture is typically the hardest component to find this time of the year because the cold polar air makes its way down from Canada and its typically very very dry. But this time we have an abundance of moisture. If you have made it outdoors over the last 2 or 3 days, you will have noticed something very quickly......fog. In order for fog to form, your dew point (an easy measurement to determine moisture in the atmosphere) has to be really close to your temperature. If it is close, you can get fog to form and that shows that there is a lot of moisture in the atmosphere. So, if you look at the current surface map below, notice the green numbers (dew point) and the red numbers (temperature) are really close together.

The third component is lift. Basically you get lift from an area of low pressure. Well what do you know, we have one of those nearby. Take a look below.

Now notice that we not only have one area of low pressure that's going to go by, but we have two, as you can see by the arrows. That's where we get our last component; long duration. The first low will weaken and go by us by tomorrow afternoon. But the second low will begin its trek toward the state and then begin to stall out nearby. That will keep all of these components in our neck of the woods through Saturday which will keep the snow around until then too. Look at the forecasted track of the second low.This is a forecast for the location of a low pressure at 12 hours increments. Each color has its own 12 hour window. Also notice that once the low pressure gets nearby it begins to stall. You can see this by counting the amount of lows around South Dakota. Each low represents a 12 hour time frame. Meaning that the low will be spinning its wheels in Iowa for 36 hours and rotating snow in our direction over and over again. This is the duration that I was talking about. So, we have forecasted ALL four ingredients for a major snow storm and that's why we are talking about so much snow. Now keep in mind that the longer that low stays in Iowa, the more snow we will get. So the totals you see on the news are not set in concrete because things can and do change. However, based on the information given to us, it looks good for large amounts of snow, so enjoy!!!

~KDLT Meteorologist Cody Matz