The title of today's IEM Feature is an acronym representing the Global Forecast System (GFS) Model Output Statistics (MOS). MOS attempts to adjust physical model output by applying known biases of the model to predict a local weather station's observations. The featured chart displays the combination of a time lagged ensemble of MOS forecasts along with the actual observations for the Des Moines Airport. The bars represent the range in values present with the MOS forecasts. The GFS MOS has been running a bit warm this month with its predictions of high temperature. No forecasting system is perfect, it is one of the many tools forecasters use to make a forecast.

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