While weather forecasts have significantly improved over the last 20 years, providing more advanced warnings of severe weather, forecasts can still sometimes be wrong. Accurate forecasting depends on data from over 11,000 worldwide observation stations measuring temperature, humidity, and other factors. Meteorologists must interpret competing computer models and real-time data, but predicting exact locations and amounts remains difficult due to imperfect tools and conflicting models. Continued technological advances may help reduce uncertainty over time.