The Role of Water Vapor in African Easterly Wave Evolution and Tropical Cyclogenesis

Abstract

A major hindrance to progress on the topic of tropical cyclone genesis is our limited understanding of interactions between mesoscale processes and the TC seedling and how these interactions are in large part driven by water vapor. In this talk, I'll assess the multi-scale and moisture-dependent nature of African easterly wave (AEW) tropical cyclogenesis (TCG) using observations and in both parameterized and convection-permitting simulations. First, I will go over past work that motivated my current research on the phasing and relative propagation between AEW and MCSs and how it affects the likelihood of TCG. Then, I will discuss the key large-scale monsoonal features over Africa that relate to TCG in the Atlantic. In the second part of the talk, I will focus on the pre-Helene (2006) TCG case using Model for Prediction across Scales–Atmosphere (MPAS-A) simulations. I will show that MPAS-A is capable of reproducing the growth of the case and that its TCG was driven by moisture and convection co-located with the wave vortex, characteristic of moisture modes. Finally, I will present my most recent research on moisture sensitivity, using convection-permitting simulations to further understand the role of moisture in tropical cyclogenesis. Concluding remarks will include the broader impacts of this work in the prediction of TCG and a glimpse of other collaborative projects I've been involved with.

Speaker Bio: Kelly Núñez Ocasio is an Advanced Study Program (ASP) Postdoctoral Fellow at the Mesoscale and Microscale Meteorology Lab (MMM) at the National Center for Atmospheric Research (NCAR). She received her Ph.D. from the Pennsylvania State University where she worked on mesoscale convective systems, African easterly waves, tropical cyclogenesis, and African weather and climate using both observations and model data. Before pursuing her Ph.D., she completed a Bachelor of Science in Theoretical Physics and a Curricular Sequence in Atmospheric Sciences from the University of Puerto Rico at Mayagüez. Dr. Núñez Ocasio is an Academia Ambassador in the AMS Committee for Hispanic and Latinx Advancement (CHALA). Her recently open-access mesoscale convective system tracker was used in the NASA CPEX-CV and PRECIP field campaigns this summer as a forecasting tool.

Seminar Contact: psl.seminars@noaa.gov