Grass-Cast Southwest: A seasonal rangeland productivity forecast for the southwestern United States

Cambridge Prisms: Drylands
By: , and 

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Abstract

Here, we present a first assessment of the US Department of Agriculture’s (USDA) “Grass-Cast Southwest,” which is a forecasting tool for rangeland aboveground net primary productivity (ANPP) for the southwest region of the United States. Our results show that ANPP forecasts in early April were relatively close to the observation-based ANPP estimates in late May for all years evaluated (R = 0.6–0.9). The relatively high predictability of spring rangeland productivity in this region is likely because it is strongly driven by antecedent winter/early spring precipitation. Conversely, the first summer forecasts produced in June did not consistently predict the final observation-based ANPP estimates in late August (R = −0.5–0.7), likely because summer rangeland productivity in this region is highly dependent on variable, less predictable precipitation from the North American Monsoon (NAM). Antecedent El Niño Southern Oscillation (ENSO) indices could be used to improve Grass-Cast Southwest performance in both the spring and summer. The ENSOJFM (January–March) index was significantly positively correlated with rangeland productivity during the spring season, whereas ENSOMAM (March–May) was significantly negatively correlated with rangeland productivity during the summer season.

Suggested Citation

Aguilar-Cubilla, E., Hartman, M.D., Parton, W.J., Reed, S., Derner, J.D., Schulte, D.K., Gornish, E., Moore, D.J., Elias, E., Peck, D.E., Fuchs, B.A., and Smith, W.K., 2025, Grass-Cast Southwest: A seasonal rangeland productivity forecast for the southwestern United States: Cambridge Prisms: Drylands, v. 2, e16, 11 p., https://doi.org/10.1017/dry.2025.10013.

Study Area

Publication type Article
Publication Subtype Journal Article
Title Grass-Cast Southwest: A seasonal rangeland productivity forecast for the southwestern United States
Series title Cambridge Prisms: Drylands
DOI 10.1017/dry.2025.10013
Volume 2
Publication Date November 28, 2025
Year Published 2025
Language English
Publisher Cambridge University Press
Contributing office(s) Southwest Biological Science Center
Description e16, 11 p.
Country United States
State Arizona, New Mexico
Additional publication details