Examining Trends in Satellite-Detected Overshooting Tops as a Potential Predictor of Tropical Cyclone Genesis

A geostationary satellite-derived cloud product based on an overshooting top (OT) detection algorithm is utilized to identify OT activity associated with Atlantic tropical disturbances. Detected OTs can serve as a proxy for vortical hot towers, which have been linked to tropical cyclone (TC) genesis. The forecast skill potential is explored by examining thresholds of OT activity and trends.

The OT algorithm is examined as a predictor both on its own and in a multi-parameter genesis forecast scheme. TC genesis forecast skill is explored by examining OT activity and trends within a 200 km radius of a “marsupial pouch” center. An independent analysis of marsupial pouches from 2011 reveals the empirically-based OT scheme is skillful at predicting if a pouch will develop at some point in the future. Analysis is also undertaken to predict when the pouch will undergo genesis.

In addition, OTs are also added to a linear discriminant analysis, which predicts TC genesis within the subsequent 24 hours. Analysis from 2009 and 2010 indicates the OTs has the potential to further improve the forecast skill of genesis.