This research addressed the hypothesis that spring precipitation data can be used to detect agricultural drought early in the growing season. The Rangetek range model was used to simulate yearly forage data based on historical precipitation and temperature records from the USDA-ARS Fort Keogh Livestock and Range Research Laboratory (Miles City, MT) and the Agriculture and Agri-Food Canada Manyberries Substation (Lethbridge, AB, Canada). Monthly total precipitation and monthly average maximum and 1 Research was conducted under a cooperative agreement between USDA Agriculture Research Service and the Montana Agriculture Experiment Station. Mention of a proprietary product does not constitute a guarantee or warranty of the product by USDA, Montana Agriculture Experiment Station, or the authors and does not imply its approval to the exclusion of other products that may also be suitable. The USDA-ARS Northern Plains Area is an equal opportunity and affirmative action employer and all agency services are available without discrimination.