'Thunder CL' (Reg. No. CV-1031, PI 655528) hard white winter wheat (Triticum aestivum L.) was developed by the Colorado Agricultural Experiment Station and released in August 2008 through a marketing agreement with the Colorado Wheat Research Foundation. In addition to researchers at Colorado State University (CSU), USDA-ARS researchers at Manhattan, KS, St. Paul, MN, and Pullman, WA, participated in the development of Thunder CL. Thunder CL was selected from the cross KS01-5539/CO99W165 made in 2000 at Fort Collins, CO. KS01-5539 is an unreleased experimental line from Kansas State University with the pedigree FS2/KS97HW150//KS97HW349, and CO99W165 is an unreleased experimental line from CSU with the pedigree KS92WGRC25/'Halt'. Thunder CL was derived from a population advanced from the F 2 to F 4 by single-seed descent. Thunder CL was selected as an F 4:5 line in September 2003 and assigned experimental line number CO03W239. Thunder CL was released because of its superior grain yield under nonirrigated and irrigated production conditions in eastern Colorado, it carries the Als1 gene for tolerance to imazamox herbicide, it is moderately resistant to wheat streak mosaic virus, stripe rust (Puccinia striiformis f. sp. tritici), and stem rust (P. graminis f. sp. tritici), and it has superior milling and bread baking quality.