Not sure what this specific B38M was here for (link to FR24?), but Boeing used to commonly send test aircraft to KMHR for Xwind testing. This is because once the Diablo Winds (The dry, offshore north winds) come, KMHR runway orientation is perpendicular to the winds (in other words, not designed for the offshore winds), on a day with strong offshore winds, KMHR can easily get 35KT Xwind component, the Boeing 787 did some testing here....