Our group specializes in using numerical simulations to better understand the dynamics, predictability, and multi-scale impacts of tropical cyclones, mesoscale convective systems, and severe convective weather. Some of our recent and ongoing research is detailed below. We gratefully acknowledge support from NSF, NOAA, and UWM for this research.
Tropical Cyclone-Midlatitude Flow Interactions
The interaction of a tropical cyclone’s diabatically driven outflow with the antecedent midlatitude pattern can reconfigure the downstream flow over one or more synoptic-scale wavelengths. The specific outcome of this interaction is sensitive to the structure of the midlatitude waveguide and the phasing of the cyclone with the midlatitude waveguide. Our group conducts research to document the extent to which the downstream response can modify the tropical-to-subtropical environment, particularly as it relates to its favorability for tropical cyclone formation and maintenance, and thus better understand the role of tropical cyclones in the climate system.
Overland Tropical Cyclone Intensity Change
Tropical cyclones are primarily fueled by enthalpy fluxes from an underlying warm ocean. However, some tropical cyclones have reintensified over land, even in non-baroclinic environments (i.e., absent large-scale forcing for ascent from an upstream trough). While it is generally accepted that making the surface more water-like is needed to permit overland reintensification, the precise processes at the land-surface interface and in the upper soil that can lead to a tropical cyclone intensifying over land are not yet agreed upon. Our group conducts research to better quantify these processes using both idealized and real-data numerical simulations.
Tropical Cyclone Intensity-Change Prediction
Although improved observational capabilities and data-assimilation methods have led to significant advances in high-resolution dynamical models’ ability to provide skillful tropical cyclone intensity forecasts, statistical-dynamical models like SHIPS and LGEM remain some of the most skillful intensity guidance. Our group is using a novel machine-learning approach called evolutionary programming to develop a skillful model for deterministic tropical cyclone intensity forecasts and probabilistic rapid intensification and rapid weakening forecasts. Evaluation of this model in the Joint Hurricane Testbed is ongoing.
Storm-Scale Environments and Predictability
Successful predictions of thunderstorms and their hazards are reliant upon accurate depictions of the storm-scale environment. Our group conducts research to quantify the ability of high-resolution numerical models, whether current or next-generation, to successfully forecast storm-scale environmental conditions, and to identify fundamental shortcomings in these models (e.g., sea-surface temperature representation) that limit predictive skill.
Mesoscale Convective Systems
Mesoscale convective systems are important contributors to the warm-season precipitation climatology of the central and eastern United States. Our group conducts research to better understand MCS dynamics, particularly rear-inflow jet structure and evolution, and document how uncertainty in convection initiation forecasts influences MCS predictability. We are also interested in how MCS intensity, structure, and propagation are influenced by mesoscale environmental heterogeneity.
We actively welcome new collaboration with prospective graduate students and other scientists on topics of mutual interest. For a full publication listing with accessible summaries, please see the Publications page. A simple publication listing is available in Prof. Evans’ Curriculum Vita. Citation information is available in Prof. Evans’ Google Scholar profile.
Nevius and Evans (2018)
- The influence of vertical advection discretization in the WRF-ARW model on capping inversion representation in warm-season, thunderstorm-supporting environments
Evans et al. (2018)
- An evaluation of paired regional/convection-allowing forecast vertical thermodynamic profiles in warm-season, thunderstorm-supporting environments
Prince and Evans (2018)
J. Appl. Meteor. Climatol.
Evans et al. (2017)
Mon. Wea. Rev.