Many iPhone users are checking their Weather app today and seeing a 100% chance of snow, with amounts ranging from 11 to 18 inches for Thursday, depending on where they live. While that sounds exciting, it’s very unlikely that the weather can be predicted with 100% certainty just one day in advance, let alone a week ahead.
Yesterday, we mentioned that the National Weather Service (NWS) Climate Prediction Center in College Park, MD reported only a ‘slight risk’ of heavy snow (20-40% chance) for the Mid-Atlantic region, including all of Maryland. This is far from 100%, and here’s why:
Most weather apps get their forecasts from just one source. This means that when you see a prediction (especially for the upcoming week), it’s based solely on the latest data from that source, without any human input to interpret it. We often overlook small temperature differences or minor rain predictions that are slightly off, but we definitely notice when the app predicts snow.
While snow is possible, it’s definitely not a sure thing at this point. As of Thursday morning, some weather models were predicting a winter storm, while others were showing rain instead. Expect a lot of changes in the forecasts over the next few days as the models try to agree on what will happen. We’ll keep an eye on the situation and provide updates as we learn more.