Evaluating the importance of convective intensity and symmetry as predictors of TC intensity change for a large database of storms in favorable environments

Wednesday, 17 December 2014
George Alvey III, Jonathan Zawislak and Edward J Zipser, University of Utah, Salt Lake City, UT, United States
Despite operational advances in tropical cyclone track forecasts, progress towards improving forecasts of intensity change has been more limited. Previous studies have separately quantified the importance of environmental conditions and convective properties with respect to intensity change; however, conjoined analyses have been rare. Using 15 years (1998–2012) of SHIPS and NCEP FNL reanalysis information for Atlantic and East Pacific storms, we analyze the sensitivity of intensity change for a detailed set of environmental parameters. Environmental conditions are then used to determine a threshold beyond which intensification is plausible. In conjunction with the environmental dataset, an expansive collection of passive microwave satellite (includes TMI, AMSR-E, and SSMI[S]) and TRMM Precipitation Radar (PR) data is used to investigate the relative importance of various convective properties (specifically those proxies for convective intensity, symmetry, and area) in storms that meet the “plausible” threshold. An emphasis is placed on evaluating the hypothesis that, when a necessary set of environmental conditions is met, intensification is favored if the inner core consists of symmetric, moderately intense convection.