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Webinar: Examining Hurricane Dorian's (2019) Early Intensification and Track Evolution Through an Ensemble of the Hurricane Analysis and Forecast System

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Wednesday, 09 February 2022, 11:00

Wednesday, February 9, 2022. 11:00 AM. Webinar: Examining Hurricane Dorian's (2019) Early Intensification and Track Evolution Through an Ensemble of the Hurricane Analysis and Forecast System. Andy Hazelton, Cooperative Institute For Marine and Atmospheric Studies. Sponsored by NOAA. More information here. Register here.

Hurricane Dorian (2019) was one of the strongest hurricanes on record in the Atlantic basin, and caused significant devastation across the northern Bahamas as it stalled out as a Category 5 hurricane. Dorian was characterized by forecast uncertainty in several aspects. In this study, we use an 80-member ensemble of the global-nested configuration of the Hurricane Analysis and Forecast System (HAFS) to examine the factors that led to the early intensification of Dorian near the Eastern Caribbean, and also the eventual long-term track with a stall over the Bahamas and offshore of Florida. For analysis of the long-term track, the ensemble is separated into 4 distinct groups, including two that hit Florida (at different speeds), one that moved quickly north of the Bahamas, and one that slowed down significantly over the northern Bahamas (closest to reality). The factors leading to the different track outcomes are examined, including the possible role of the early rightward track deviation over the Caribbean, the evolution of the subtropical ridge over the Southwest Atlantic, and the strength of a shortwave trough over the United States. The analysis performed highlights the utility of high-resolution ensembles for understanding the complex structure evolution in TCs, and also shows how large ensembles can show key details of the large-scale features that steer TCs. This research also demonstrates how the developing HAFS system can be used as a high-quality research tool to better understand the physics of TC development and movement.

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