Seasonal patterns and trends of fastest 2-min winds at coastal stations in the conterminous USA

Weather extremes have a substantial societal impact, particularly in increasingly densely populated coastal areas. This research uses 'fastest 2-min wind' records at land-based coastal automated weather stations in the conterminous United States to characterize seasonal patterns of 'extreme' wind speed. The records also are examined for evidence of trends in the fastest winds that may be indicative of changes in cyclone activity over the available period of record (13-19 years). Fastest 2-min winds at stations along the Pacific, western Gulf, and northern Atlantic coasts have a winter maximum and a summer minimum, similar to the seasonal variation in mean wind speeds. In contrast, the fastest winds at southern Atlantic and eastern Gulf coast stations show a winter minimum and a summer maximum that is opposite what is observed for mean speeds. Over the period of available record, many coastal stations show positive trends in the fastest 2-min wind speeds in winter, spring and summer. Negative trends are most frequent in the autumn. On an annual basis, the trends in fastest 2-min winds are consistent with the results of satellite-derived near-coastal oceanic wind speed assessments. Examination of daily weather maps and synoptic composites supports the interpretation that extratropical cyclone activity is the primary driver of the fastest wind speeds at most stations, with tropical systems and mesoscale features such as thunderstorms producing some of the fastest winds during the summer and autumn.