What’s the difference between weather forecast models?

We know many of you have to become armchair (or armrest – Snowjobs listeners know) meteorologists, too. How accurate are the different weather forecasting models? How different should I expect different weather forecasting models to be? We’ll break down the pros and cons from the perspective of the snow removal professional; each model may be better suited for different uses.

But first – how exactly is a forecast model developed? The easiest way to think about it is as a computer program that takes in current and historical weather observations and uses math and physics formulas to estimate how those conditions will change in the future. These models combine atmospheric information like pressure, wind, and temperature from airport and road weather information (RWIS) stations, Doppler radar, weather balloons, satellites, and other ancillary data points, to diagnose what is happening and predict what is going to happen.. 

Because the models are driven primarily by current conditions from weather sensors, they typically get less accurate as the forecast goes out in time. Models also tend to be more accurate over terrain that is not as challenging, like the plains, as opposed to mountainous areas where model resolution is too coarse to resolve microclimates.

In the information below, spatial resolution is the length of the bounds of a grid cell (e.g. 3 km resolution = 3 km x 3 km grid cell). Estimates are made for many different variables within that grid cell and also from neighboring grid cells in order to complete a prediction. The model is a grid of these cells that holds onto predictions over consistent time steps. The length of these time steps is the model’s temporal resolution (e.g. hourly timesteps, 1-hr resolution).