Comments on “Monitoring and Understanding Trends in Extreme Storms: State of Knowledge”

Abstract

1175 JULY 2015 AMERICAN METEOROLOGICAL SOCIETY | DOI:10.1175/BAMS-D-13-00211.1 K unkel et al. (2013) reviewed the state of the science with regards to long-term changes and trends of various extreme storms that impact the continental United States. In particular, they addressed severe convective storms, precipitation, snowstorms, and—of interest to this comment— hurricanes. All of the analyses presented in Kunkel et al. (2013) (their Figs. 1–7 and Tables 1 and 2) were focused on observations taken over the continental United States, with the notable exception of hurr icanes. Instead, their F i g . 5 pr o v i d e d d a t a (updated from Kossin et al. 2007) for the entire North Atlantic and northwestern Pacific basins going back only to 1970 in the form of power dissipation index (PDI). They did reference one study on U.S. hurricane activity (Landsea 2 0 05) a nd ment ione d that it indicated no significant long-term trends. That paper, however, is now dated because of the passing of a decade of new observations as well as revisions being made to the first half of the twentieth century U.S. hurricane record through the Atlantic hurricane database project (Landsea et al. 2008, 2012, 2014; Hagen et al. 2012). Given that Kunkel et al.’s (2013) goal was to “present a clear record . . . about what is known and unknown and why about . . . extreme weather and climate types affecting the United States” (p. 499), this comment examines the most up-to-date record of U.S. hurricanes and the associated century timescale trends. Hurricanes striking the continental United States compose a sizable percentage (23%) of all Atlantic basin hurricanes since 1972, the first year for reliable all Atlantic basin hurricane frequency owing to the invention of Dvorak satellite intensity technique (Dvorak 1975) coupled with available satellite imagery for the basin. The rather lengthy coastline of the United States tends to experience more hurricane strikes in busy seasons, but not