An Observational Assessment of Recent, Extreme Rapid Intensification Events in the North Atlantic

Hurricanes Sam (2021) and Lee (2023) underwent periods of rapid intensification (RI) that exceeded the canonical 30 kt in 24 h definition: Sam intensified 45 kt and Lee a preliminary 75 kt in the same amount of time. Both TCs exhibited slow intensification followed by a brief “pause” prior to undergoing RI. Subsequent to each storm’s explosive RI period, an eyewall replacement cycle (ERC) occurred, a process that may have been hampered by increasing vertical wind shear and dry air, resulting in rapid weakening: 30 kt in 24 h for Sam and 45 kt in 24 h for Lee.

Geostationary and low-earth orbit satellite observations will offer insight into the convective and structural evolution of these two TCs prior to, during, and subsequent to these extreme RI events. When available, SAR snapshots will provide additional insight into the structure and extent of the TC wind field. Due to its relatively high temporal and spatial resolution, rainfall estimates from the Integrated Multi-satellitE Retrievals for GPM (IMERG) dataset will also be explored during these time frames using spatial metrics. Finally, ERA5 fields will supplement the above analyses and facilitate assessment of the associated moisture environments in the context of patterns previously identified for mature North Atlantic TCs under low to moderate shear.

A QR code will be included that links to relevant animations, Python scripts, and other supplemental information.