It has been shown in this preliminary study that the effects of snow cover may not be adequately reflected in the NGM MOS minimum temperature guidance for Bismarck, North Dakota. As the snow depth increases with increasingly cold nighttime temperatures, MOS has a strong warm bias. The forecaster is, in most cases, having to adjust the forecast minimum temperatures lower than guidance suggests. When no snow or a minimal snow depth occurred, MOS was fairly close to observed morning minimums. More work needs to be done with studying how to make the NGM MOS temperature guidance better.
Snow depth appears to be an important factor, as well as the existence of snow cover.
An adjustment factor to apply to MOS to better predict low temperatures in Bismarck, North Dakota appears necessary. In addition, having an awareness of the biases in the MOS minimum temperature forecast when there is snow cover will help the forecasters in Bismarck. The author would like to thank Mr. Sam Walker for his help with figures and other staff at WSFO Bismarck, North Dakota for reviewing this manuscript and giving helpful comments. An Examination of MOS Objective Temperature Prediction Model. An Analysis of Minimum Temperature After Cold Frontal Passage.