Why is it more difficult to forecast snow?

Have you ever wondered why meteorologists say snow is difficult to forecast? Well, here are a few reasons why snow can be difficult to forecast, especially in terms of a long-range forecast.

First, is the temperature. 32° is a firm freezing temperature. Anything warmer than 32° will quickly diminish your chances of snow. It needs to freeze at the surface and throughout the atmosphere. Any warm pocket a couple of thousand feet above the ground will squash snow chances.

Another reason snow forecasts can be difficult is knowing the path of the upper-level storm system. The upper-level storm track drives the direction of the entire storm. This is tricky to pin down when a storm is 4,000 miles away. However, as the storm moves closer, its path is easier to determine.

A good example is to think of it as a pachinko game. In the image below, a nine day forecast has many more opportunities to change versus only a few days out. As the distance from the storm shrinks, so do the alternatives.

There are also 2 types of computer models: Deterministic and Ensemble.

Deterministic models produce a single outcome whereas ensemble models produce multiple different outcomes from different models. These multiple outcomes can then be averaged into one model output. This is the most reliable way to forecast long-range snow events.

A forecaster will want to identify the similarities and differences between the different ensemble members to come up with the best possible outcome.

Still, given the uncertainties in the upper-level storm track and the needed temperature in different atmospheric layers, confidence remains low regarding winter storms more than three days out.

Stay with the Ozarks First Most Accurate Weather team the next time winter weather threatens the Ozarks!