Accuracy of Frost and Freeze Forecasts for Northwestern Michigan Wine Growers

With its abundance of crops, the Grand Traverse Bay area represents an area of great economic importance to Michigan. At this latitude, freeze events pose a serious threat to the fragile Michigan wine industry. People in the agricultural business may not be sure how much trust they can place in any particular NWS forecast. The dates observed here represent potential freezes that occurred during the growing season, which typically starts towards the beginning of May, and typically ends towards the end of October, from 2011 to 2015. Data was collected for the 20 km RUC/RAP, 13 km RUC/RAP, and 12 km NAM from the NOMADS and NCDC databases. The NDFD was used to retrieve archived NWS forecasts. These four forecasts were used to evaluate which events had the highest impacts, and to calculate statistics that will help to show which forecast tool is most reliable for this area. RAP reanalysis was also performed on the most damaging dates to try to find any correlation between these events.