Satellite Signatures of Six TCs Which Rapidly Intensified in Shear

Wednesday, 20 April 2016: 12:00 PM
Ponce de Leon B (The Condado Hilton Plaza)
David R. Ryglicki, National Research Council, Monterey, CA; and J. D. Doyle and J. Cossuth

Satellite signatures of six tropical cyclones (TCs) which rapidly intensified (RI) in shear are presented. All of these TCs RI'd starting from tropical storm strength (~30 ms-1) in moderate vertical wind shear (6-10 ms-1) over warm water (>28 °C). Each storm initiates the RI process with a large, intense convective burst whose cloud top temperatures are below -80 °C followed by a series of periodic explosive convective bursts. These series of bursts serve multiple purposes. Based on microwave imagery, these bursts serve to wrap around and protect the eyewall. Based on geostationary imagery, the outflow from these bursts serves to block the upper-level winds that are shearing the storms. The environmental flow, which is limited in the vertical to very near the tropopause, both sinks, as evidenced by a clearing of the satellite upwind of the storm, and splits. The splitting of the wind results in an outflow jet on the left-side of the upper-level flow split from the perspective of the jet. By revisiting the evolution, analyses, and post-processing of Eastern Pacific Hurricane Guillermo in 1997, it is hypothesized that common features in the satellite imagery and environmental parameters link the six hurricanes together, potentially illustrating a family of TCs that follow a unique pathway to rapid intensification.
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