Early Detection of Cyclogenesis Signature Using Global Model Products

High-resolution Global Forecast System (GFS) model products are used to detect the earliest tropical cyclogenesis (TCG) signature over the North Indian Ocean (NIO). In order to identify the formation of tropical cyclones (TCs) in the model forecast fields, three parameters, namely, low-level relative vorticity, genesis potential parameter, and wind circulation pattern matching index, are examined in this paper. The detection of TCG in the GFS model is performed for 14 TCs that developed in the NIO during the 2008-2011 period. The results show that the wind circulation pattern matching index provides the most reliable guidance (high probability of detection, i.e., approximately 0.92, in a 24-h forecast with relatively few false alarms) for identifying TC formation over the NIO.