Why is predicting the strongest winds within tropical cyclones (TCs) such a challenging task? One possible reason is the uncertainty in the forecasts that originates from poor representations of TC structure in the initial conditions of numerical models. To understand how initial-time errors can lead to large intensity forecast uncertainty, my research study uses ensemble forecasts from the Advanced Hurricane Weather Research and Forecasting (AHW) model. During the past year, our research efforts have been focused on the poorly forecasted Hurricane Katia (2011) by using 96 ensemble forecasts from the AHW model. Two distinct subgroups have been identified and extensively studied:

1) 10 members that predicted a strong hurricane (named strongest members)

2) 10 members that predicted a weak storm (named weakest members)

I am currently evaluating composites of these two subsets of ensemble members to better understand the dynamics of axisymmetric TCs and to identify the type and location of observations to be assimilated into numerical models to reduce initial-time uncertainty.