Some aspects of the seasonal precipitation over eastern Patagonia, the southernmost area of South America east of the Andes Cordillera, are examined in this paper. Results indicate that the central-north areas, the southern continental region, and the southernmost islands are three independent regions of seasonal precipitation, and that each of them is associated with specific patterns of atmospheric circulation. Precipitation over the central-north region is significantly related to the precipitation over a wide area of southern South America east of the Andes during the four seasons. Enhanced (reduced) precipitation over this area is associated with weakened (intensified) westerly flow in the region. Precipitation over the southern continental area has a close connection with the dipolar pattern of precipitation over subtropical South America during spring, summer, and autumn. The anomalies of atmospheric circulation at low and upper levels associated with the subtropical dipole are also able to modulate the intensity of the westerlies over the south of eastern Patagonia, affecting the regional precipitation. Precipitation over the islands of the southernmost part of eastern Patagonia is connected with subtropical precipitation in summer and winter. The activity of frontal systems associated with migratory perturbations moving to the east along the Southern Hemisphere storm tracks modulates the variability of seasonal precipitation over this region.

The aim of this paper is to investigate different aspects of the seasonal-to-interannual temperature variability in Eastern Patagonia, the southernmost area of South America, east of the Andes Cordillera. Homogenous regions of seasonal variability and the atmospheric circulation patterns associated with warm and cold conditions in each of them are described in this study. Relationships between temperature in Eastern Patagonia and that registered in other areas of southern South America are also addressed. Results show that the northern and southern areas of Eastern Patagonia have different temperature variability in summer and autumn whereas the temperature variability tends to be more homogeneous within the region during winter and spring. Warm (cold) conditions in the northern areas are associated with reinforced (weakened) westerlies in summer, winter and spring whereas northerly (southerly) advections of warm (cold) air toward the region produce such conditions in autumn. Temperature in the southern portion of Eastern Patagonia is affected by anticyclonic (cyclonic) anomalies that enhance (reduce) the incoming solar radiation and induce reinforced (weakened) westerlies promoting warm (cold) conditions in the region. Furthermore, cyclonic (anticyclonic) anomalies at subpolar latitudes hinder (favor) outbreaks of cold air increasing (decreasing) the temperature over areas of Eastern Patagonia. The circulation anomalies associated with warm (cold) conditions in Eastern Patagonia also promote cold (warm) conditions over areas of northern Argentina, Paraguay and southern Brazil. Consequently, a dipole of temperature is detected in southern South America with centers of opposite sign over these regions.

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