The waves in Hurricane Juan

Hurricane Juan made landfall near Halifax Nova Scotia as a category 2 hurricane with winds of 44 m/s, the largest storm to pass over these coastal areas in several decades. Associated high ocean waves were experienced in coastal waters, from Peggy��s Cove to Sheet Harbour, growing to epic proportions on the Scotian Shelf, and exceeding the 100-year return wave based on the present climatology. As part of the wave modelling program at BIO/ Dalhousie, we have implemented and compared three widely-used third generation numerical wave models, SWAN, WAM and WaveWatch-III (hereafter WW3) for accuracy, with in situ measurements. Wave measurements were made using four operational deep-water buoys (C44258, C44142, C44137, 44005), by a conventional directional wave rider (DWR) moored offshore from Lunenburg Bay, and also by two acoustic Doppler current profiler (ADCP) located (1) near an oil rig on Sable Island Bank, in relatively shallow water, and (2) near the outer boundary of Lunenburg Bay. We present discussion of the reliability of DWR wave data compared to ADCP wave data. We show that all models provide reliable hindcasts for significant wave height (Hs) and for peak period (Tp) for Juan, although a clear under-estimation of Hs at the peak of the storm is evident, compared to observations. A feature in the numerical weather forecast winds (from the US Navy operational center in Monterey) is that the storm track appears to be slightly to the east of that presented by Quikscat scatterometer data and the Canadian Hurricane Centre analysis. Recommendations for improvements in models and forecast methodology are presented.