<p>The role of land–atmosphere interactions in climate predictability is well-recognized at subseasonal-to-seasonal timescales, particularly for the U.S. Great Plains. This study provides new estimates of the effects of land surface interannual variability on April–September hydroclimate in the U.S. based on a novel idealized modeling experiment using the advanced, convection-permitting WRF/Noah-MP model with multi-layer snowpack and explicit groundwater and vegetation dynamics. The experimental design seizes on recent extreme dry and wet years in the southern Great Plains, 2011 and 2019, respectively, to capture the maximum range of land surface anomalies. Differences between an anomalously wet 2019 simulation and a 2019 simulation with snow, soil moisture, and soil temperature nudged daily to anomalously dry 2011 states highlight substantial and significant land surface effects on regional atmospheric circulation, Great Plains low-level jet intensity and positioning, wind power generation, and terrestrial and atmospheric water budgets. Comprehensive analyses of land-forced hydroclimate variability are presented for the southern, central, and northern Great Plains at diurnal and monthly time scales. One major finding is that dry 2011 land conditions cause 30–40% increases in wind power generation over the central Great Plains in August and the southern Great Plains in June, August, and September. Overall, land nudging is shown to significantly affect precipitation, runoff, evapotranspiration and the diurnal temperature cycle, but ultimately, large-scale atmospheric forcing explains a greater fraction of interannual variability of hydroclimate, windspeed, and wind power generation.</p>