Abstract: Equations are presented for the evolution of isobaric shear and curvature vorticity and for isentropic shear and curvature potential vorticity in natural (streamline-following) coordinates, in the case of adiabatic, ...

Abstract: The leading tropical multidecadal mode (TMM) and tropical interannual (ENSO) mode in the 52-yr (1949? 2000) NCEP?NCAR reanalysis are examined for the December?February (DJF) and June?August (JJA) seasons based on seasonal ...

Abstract: Interannual and multidecadal extremes in Atlantic hurricane activity are shown to result from a coherent and interrelated set of atmospheric and oceanic conditions associated with three leading modes of climate variability ...

Abstract: This paper presents an observational analysis of the large-scale atmospheric circulation prior to and during the Midwest floods of June?July 1993. The floods developed and persisted in association with three major circulation ...

Abstract: A 15-year (1963?77) Northern Hemisphere 2 ? 5 degree latitude-longitude gridded dataset of 500 mb geopotential heights has been used to construct a climatology of 500 mb closed circulation centers. These centers, defined ...

Abstract: The synoptic-scale evolution during the formation phase of a midtropospheric cutoff cyclonic circulation over the eastern United States is diagnosed within the potential vorticity framework using the GALE (Genesis of ...

Abstract: Appalachian cold-air damming is investigated by means of 1) a 50-yr monthly climatology, 2) a synoptic case study of the event of 21?23 March 1985 and 3) an investigation of the flow structure and force balance within the ...

Abstract: Observational composites of midtropospheric closed cyclone formation are constructed and diagnosed for three regions: the southwestern United States, the eastern United States, and the southern lee of the Alps. The spatial ...

Abstract: The global climate during 1997 was affected by both extremes of the El Niño?Southern Oscillation (ENSO), with weak Pacific cold episode conditions prevailing during January and February, and one of the strongest Pacific ...

Abstract: The climate of 1996 can be characterized by several phenomena that reflect substantial deviations from the mean state of the atmosphere persisting from months to seasons. First, mature cold-episode conditions persisted ...