It’s That Time of Year For Snow Maps to Appear. Here’s What You Should Know About Them and Why You Shouldn’t Always Believe Them

Major winter storms affect the United States every year, and due to their heavy impact on everyone's lives, the biggest question asked is: How much am I going to see? The eagerness to know how much impact a snow or ice storm will have is understandable, but unfortunately, sometimes that question cannot be answered until within one to three days of its arrival.

Meteorologists don't simply key on one model, but rather examine multiple numerical models, and their evolution over time, using their expertise on each model's strong and weak points, or biases. For example, on a Monday morning, there may be indications in forecast model guidance that a winter storm could affect several regions of the United States the following Friday through Sunday. Instead of specific details, meteorologists usually give a head's up that we are watching for a particular storm in a general timeframe. This is typically followed by the caveat that the forecast will change and we will provide more details as they are available.

So the next time there is a potential for a significant winter storm in your area, resist the temptation to run with the forecast on any snow map(s) you might encounter on social media. Instead, consider the source. If the person who posted the image isn't a familiar face that you've seen on TV, a trained meteorologist from the National Weather Service or private forecast company such as The Weather Channel, a quick Google search of their name will almost always tell you in less than 30 seconds if this is a reputable source. Trained meteorologists should not be sharing a wild forecast for a week into the future, and if you can't find the person's portfolio and credentials in a web search, that's a red flag.

https://www.wunderground.com/news/storms/winter/news/2018-12-03-snow-winter-forecasts-maps-social-media