Unique observations of Hurricane Patricia depict structural evolution during rapid intensity changes

What is it about?

Hurricane Patricia (2015) experienced a remarkable rapid intensification of 150 knots in 24 hours, followed by an equally noteworthy over-water rapid weakening of 50 knots in five hours. Numerical models failed to predict the magnitude of Patricia's rapid intensity changes amidst an environment conducive to rapid intensification and primarily absent detrimental factors, typifying our incomplete understanding of tropical cyclone intensity change. A novel, comprehensive set of observations was collected in Patricia during the concurrent Office of Naval Research Tropical Cyclone Intensity (TCI) experiment and the National Oceanic and Atmospheric Administration Intensity Forecasting Experiment (IFEX). The unique dataset permitted analyses of Patricia in a manner previously unattainable for tropical cyclones. High-resolution analyses were created at three critical stages during Patricia's life cycle: rapid intensification, near maximum intensity, and rapid weakening. Our principal findings elucidate Patricia's structural evolution and provide further insight towards understanding the mechanisms internal to a tropical cyclone experiencing rapid intensity changes.

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Why is it important?

To the date of Patricia's occurrence, it was classified as the most intense tropical cyclone observed by aircraft and experienced the most rapid intensification of any observed tropical cyclone (both defined by wind speed measurements). The fortuitous coincidence to observe Patricia's phenomenal evolution with a novel observing system provided a rare opportunity to better understand tropical cyclone intensity change. We presented the first full-tropospheric calculation of Ertel's potential vorticity from observations in a tropical cyclone without relying on balance assumptions. Analyses of Patricia's structural evolution from a potential vorticity perspective revealed new insights to the processes associated with tropical cyclone rapid intensification and rapid weakening. Our results further demonstrate that a potential vorticity framework is well suited for distinguishing internal processes associated with tropical cyclone intensity change.