Verification of the NMC 6–10 Day Temperature Outlook

Abstract

Verification has been completed for the NMC 6?10 day temperature outlook. The sample size involves 100 forecasts at each of 14 locations distributed uniformly across the continental United States. A separate regional analysis was performed at six locations in the northeastern United States. The overall results indicate a marginal forecast skill versus climatology. Greatest skill is exhibited for much below normal forecasts which comprise 8% of all forecasts. Also, a conservative bias is observed in the outlook, as extreme temperature anomalies (i.e., much above and much below normal) are predicted less frequently than they are observed. The results also exhibit a striking similarity to the results of persistence-based forecasts, thus indicating that persistence is a principal source of guidance used in the forecast.