Tuesday, 24 January 2017
4E (Washington State Convention Center )
In October of 2015, Hurricane Patricia stormed through the eastern Pacific to become the strongest recorded hurricane in history. Within a twenty-four hour period, Patricia’s maximum wind speed increased by 105 kt, while the sea level pressure decreased by 95 hPa. At its greatest intensity, the storm reached an estimated maximum wind speed of 185 kt and a minimum sea level pressure of 872 hPa. Operational weather prediction models failed to accurately forecast Patricia’s intensity evolution, provoking questions about the factors behind this unparalleled case of hurricane rapid intensification. In this study, a high resolution numerical weather prediction model (WRF) was employed to simulate Hurricane Patricia to shed light on the environmental conditions during its rapid intensification. An analysis of the WRF model fields demonstrated that environmental variables such as vertical wind shear, sea surface temperature, and relative humidity were extremely favorable for intensification (e.g., the shear briefly dropped to < 1 m/s). The environmental conditions during Patricia’s rapid intensification were compared with the corresponding quantities from a 30+ year climatology of hurricanes in the Eastern Pacific, revealing that sea surface temperature and relative humidity values fell into the 99th percentile. This indicates that the storm environment played a substantial role in Patricia becoming the strongest hurricane on record. It additionally suggests that potential future cases of extreme rapid intensification can be predicted if the models are able to capture the environmental conditions.
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