I often highlight how far forecasts of extreme weather events have come in the last ten years. Still, there are times when the forecast can be difficult and these generally involve small scale weather features. Take a look at this computer model forecast of moisture (in this case the water content of melted snow, not rain) for the next two days:
The northern band of snow shows heavy snow (dark blue) from southeast Nebraska and northeast Kansas across northern Missouri. The light blue is potentially more than eight inches. This forecast has good chance of being approximately correct.
Now, look at the southern band of snow. If you look closely you can see an area of dark blue, (4-8″ of snow) about ten miles wide, on the Kansas-Oklahoma border. Then, just 30 miles south the forecast is for zero snow! The chance of this forecast being exactly correct? Poor to fair.
While the pattern is may be correct, the exact placement (location) of the narrow heavy snow band is smaller than our techniques can account for. If the system moves 40 miles north (and that is possible, but not likely), Sedgwick County’s 500,000 residents get an unpleasant surprise with 4-8 inches as opposed to the 1-2 inches indicated by the model.
It is a fact of life for meteorologists that you measure our success by how much snow fell at your home and we don’t get any “extra credit” for being correct 30 miles away. That is fine with us. I just want to let you know how some snow-producing weather systems are more “forecastable” than others.