Dr. Fiorino presented a seminar “Deterministic Tropical Cyclone Genesis in a Suite of Operational Global Models. Part II: Verification and Spurious model TCs“.
In Part I of this paper, presented at NHC two days ago, we describe a data set of developing/non-developing tropical disturbances (‘pTCs’ for pre/potential TCs), and how this data set is a necessary condition for verification of deterministic TC genesis. Part II defines operational TC genesis and demonstrates that through a detailed comparison of model TCs (defined by the GFDL tracker), and observed pTCs and TCs, we can verify model genesis and quantify spurious model storms or ‘spuricanes’ (false alarms).
The talk will start with the basics of TC genesis — both the history and dynamics — and how/why the current suite of top-tier operational global NWP models of ECMWF, UKMO and NCEP are impressively successful in 2- and 5-d genesis forecasts and how skill varies by basin. The analysis of model TC genesis and spuricanes also reveals striking differences in model physics, especially in total basin rainfall and the partitioning of convective v large-scale precipitation.
Results will focus on the 2015 season in the most active northern Hemisphere basins (WPAC/CPAC/EPAC/LANT). We will also show how the success of the models is a relatively recent phenomena and is related to their success in track prediction, most notably how ECMWF shattered records for mean 72-h position error in 2015.
The presentation is available on the anonymous ftp site: