The climatology of extremely high warm‐season temperatures and their sensitivity to climate change

Understanding the climatology of extremely high warm‐season temperatures is essential for predicting their sensitivity to climate change. An idealized model that uses proxies for daily variations in thermal advection and solar radiation explains more than half of the spatial variance in the average magnitude of extremely high warm‐season temperatures in a global climate model ensemble and more than one‐third of the variance in station observations. The idealized model quantifies the contribution of changing thermal advection patterns and solar radiation variability to the changing magnitude of extremely high warm‐season temperatures found in global warming climate model simulations; it also demonstrates that extremely high temperatures are more sensitive to changes in radiative forcing than the mean temperature is. Long‐term observed trends in extremely high temperatures can be partially explained by the results presented here, but the idealized physical model also demonstrates that long‐term soil moisture trends, which are difficult to predict or observe, dramatically modify trends in the magnitude of extremely high temperatures.