IEM Daily Feature
Thursday, 14 November 2013

Bad Forecast?

Posted: 14 Nov 2013 05:37 AM

A prominent meteorological forecast model, North American Mesoscale (NAM), run by the National Centers for Environmental Prediction produced what would appear to be a very bad forecast for near surface air temperature on Wednesday. The featured map shows the forecasted temperature bias for noon with many sites in the upper midwest around 10 degrees too cold. On the surface, this would appear to be a bad forecast, but there was a reason why the temperatures were too cold. The shaded areas on the map show analyzed snow depth that the model was provided to start the forecast. Of course, these snow depths are way off with much of Iowa shown in the 1-3 inch range, whereas reality was just a trace, if that. So the worst temperature predictions are shown over areas with incorrectly analyzed snow depth. This begs the academic question of if this was a bad forecast or an example of garbage in - garbage out?

Good = 32
Bad = 2
Abstain = 4

Tags:   model   forecast