Putting Frontogenesis on the Map

There is beauty to the synthesis of theory and practice. Theory makes sense of apparent chaos, and practice reminds us it’s not that simple. Dr. Dan Keyser understood this dichotomy and has advanced frontogenesis from a concept into operational application. With roots in the Bergen school of thought almost a Century ago, frontogenesis is used to describe the formation or intensification of a frontal zone. Guided by new observations, Dr. Keyser used frontogenesis calculations to describe a more flexible view of the evolution of fronts, with the Shapiro-Keyser frontal model. The 1980s also saw the explicit modeling of the ageostrophic circulation induced by frontogenesis, more directly linking frontogenesis to precipitation features. The advance of gridded datasets in the 1990s made the calculation of frontogenesis easier and frontogenesis quickly became a mainstay function in meteorological analysis software. Studies of the 1990s and 2000s further linked the evolution of frontogenesis with the evolution of precipitation features, such as snowbands and rainbands. Today, frontogenesis is the ‘go to’ diagnostic used in real-time operational and official mesoscale analyses, is prominent in popular model websites, and is commonly referred to in forecast discussions. Frontogenesis is on the map.

This talk will review the evolution of frontogenesis from concept to operations, with emphasis on the most recent two decades. This talk will also discuss how the application of frontogenesis relates to a vision of a 'play-by-play' of the radar for extratropical cyclones - as Dr. Keyser put it, “like they do for severe weather.” Motivated by understanding the ‘why’ behind the radar evolution, frontogenesis helps answer that question for many radar features. However, as our mesoscale and microscale understanding of snowstorms evolves, perhaps frontogenesis has been a pathfinder for other diagnostics revealing the myriad of other features embedded in cyclones, such as gravity waves, bores, microphysical processes, Kelvin Helmholtz waves and other phenomenon. Perhaps Dr. Keyser's vision of the ‘play-by-play’ of the radar may not be far away.