A33L-3366:
Evaluation of Tropical Cyclogenesis Forecasts in Different Synoptic-Scale Environments
Wednesday, 17 December 2014
Weiwei LI, University of Illinois at Urbana Champaign, Urbana, IL, United States, Zhuo Wang, University of Illinois, Urbana, IL, United States, Melinda Peng, Naval Research Lab, Monterey, CA, United States and Ron McTaggart-Cowan, Numerical Weather Prediction Research Section, Meteorological Service of Canada, Dorval, QC, Canada
Abstract:
The prediction skills of the tropical cyclogenesis over the Atlantic are examined using the GEFS Reforecast for different genesis pathways. Among the five genesis pathways identified by McTaggart-Cowan et al., the strong tropical transition pathway, in which the upper-level forcing plays an important role in genesis, has the lowest probability of detection (POD), while the low-level baroclinic pathway has the highest probability of detection but the false alarm rate is also much higher. The week-1 reforecasts show high prediction skills when the model is initialized at phase 2 or phase 3 of the MJO (based on the Wheeler-Hendon index). Such sensitivity, however, disappears as the MJO signals attenuate in the week-2 reforecasts. The large-scale circulation biases related to the tropical cyclone forecast errors are also investigated.
