A meteorologist's job is never done. The forecast is studied several times a day in hopes of finding some consensus between the model runs, current conditions, and past observations. This task is most difficult when it comes to forecasting snow. A lot of you may think that we like to ride the fence or "Air" on the side of caution, but in fact, there is a lot to consider when it comes to putting together the forecast. You think that being President of the US will give you gray hair, try forecasting a potential snowstorm for five million busy people across the Upper Midwest. DISCLAIMER: "No, I am not saying my job is harder than being President…LOL".
Below are 3 scenarios that can GREATLY affect our upcoming snow event!
This is the most important factor in any storm. The low pressure pulls in the moisture from the south and the cold air from the north. It is just north of the center of circulation that most of that comes together to form the snow. Simply put, the farther away from that center of circulation, the less precipitation.
Whether it is coming from above or below, dry air can eat up our snow or sharply cut it off. The main ingredient in all snow events is the presence of cold air to give us the snow in the first place. This week we will see that cold air come in from Canada in a big way. However, that air is as dry as a bone, so it can also counteract the moisture that is pulled in from the storm. Check out the dewpoint map below and you can clearly see that cold and DRY air in our upcoming snow event.
The dry air can also come in from down south. The "Dry Tongue" is always around in any low pressure system. You have most likely heard us refer to it as the dry slot
By definition, low pressure generally pulls in moist air from the south and cold air from the north. The moist air rises over the denser cold air, condenses and forms precipitation. However, there are also areas of sinking air, where clouds and precipitation can't form. These "Dry Slots", will completely shut off the snow machine.
RAIN AND THUNDERSTORMS
On the southern side, and warmer side, of this storm we will see rain and even some thunder. That rain and those storms will take the Gulf moisture and ring it out. So, in theory, if the rain and thunder gets intense, they can dump all that moisture before it has a chance to get up to us, thus resulting in less snow.
Hopefully this blog will give you some insight in all that factors that go into producing big snow for the Upper Midwest and maybe give you a little more compassion in just how difficult forecasting can be.
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