Cooperative Institute for Research in the Atmosphere

Part 2: Preliminary Analysis of Wind Gusts in Recent Landfalling Hurricanes

Forecasting the timing and magnitude of tropical cyclone rapid intensification (RI) remains an ongoing forecasting problem.  Although the ability of deterministic tropical cyclone intensity models to forecast such events has improved, their skill remains inadequate. Thus, forecasters have relied on other tools such as the SHIPS suite of probabilistic statistical rapid intensity models to aid with the forecasting of RI. Since the start of the 2016 Hurricane Season, the SHIPS RI model guidance suite has provided operational RI forecasts at multiple lead times (12, 24, 36, 48 and 72-h) rather than the single lead time of 24-h for which it was originally developed. In our upcoming presentation, a verification of those operational multi-lead time forecasts as well as a discussion of preliminary efforts to improve those existing statistical RI models using storm structure information will be provided.

Although wind gusts produced by tropical cyclones are important for operational forecasting, building design, and for use in tropical cyclone damage models; explicit operational numerical model forecasts of wind gusts are currently not provided. Thus, forecasters and engineers typically apply gust factors that had been determined in previous studies to forecast wind gusts in real time. In our present study, high resolution surface wind observations obtained from the National Center for Environmental Information are utilized to compute gust factors in recent landfalling hurricanes Harvey (2017), Irma (2017), Florence (2017), and Michael (2017). Preliminary results from the analysis of the distribution of gust factors in those four storms will be discussed in our upcoming presentation.