This article reports on a mentoring case from a transdisciplinary, longitudinal writing-across-the-curriculum (WAC) initiative in which the situated complexities of integrating new writing pedagogies were observed and supported. Considering this case through an agential realist lens, we introduce the concept of "discursive turbulence": an emergent quality of situated semiotic activity produced from the continual mixing of discourses. Discursive turbulence can emerge in myriad and complex ways, including fits-and-starts of pedagogical development, mismatched discursive alignments, affective signs of struggle and intensity, and nonlinear patterns of change. Through a series of four vignettes, we illustrate discursive turbulence as it emerged while pedagogical changes around writing were being implemented by an environmental sciences professor. We suggest that discursive turbulence is to be expected in heterodisciplinary spaces, and we argue that attention to discursive turbulence will lead to more robust accounts of learning, becoming, and literate activity, as well as new ways of supporting pedagogical becoming.