Preliminary Numerical Simulations of Sudden Warming from Chinooks in the Lee of the Alaska Range

Southerly foehns off the Alaska range, where such winds are called chinooks, can raise 2-m temperatures in the lee of the mountains by tens of degrees (C) in just minutes. Mesoscale numerical weather prediction models often struggle to predict accurately the timing, magnitude, and spatial distribution of these sudden warmings. The authors will use idealized and realistic simulations of chinooks to begin exploring how these warmings occur, why they are difficult to predict, and what improvements can be made to numerical models and their initial- and boundary conditions to increase predictive skill. A particular focus of the study is the shallow, strong cold pools in the lee of the Alaska Range that precede some chinooks. These cold pools set the stage for sudden warming and, as the authors hypothesize, might partly explain why such situations are so challenging for mesoscale models.