Synoptic and regional-scale conditions associated with precipitation events leeward the Andes in Argentina are studied. Anomaly patterns of mid-tropospheric circulation in conjunction with local precipitation are analysed from Tartagal (about 20\ub0S) to Usuhaia (about 55\ub0S) mainly along the longitude 70\ub0W east of the Andes cordillera in order to examine the anomaly circulation behaviour and seasonality, and also to detect spatial coherence and geographical differences in anomaly patterns having place in precipitating situations. It is worth noting that each one of the regional synoptic map-pattern classifications investigated are appropriate or of exclusive use for the corresponding surface station. There exist separate classification systems for each in situ precipitation, thereby, different responses for each station. Notwithstanding, north of Malargüe (about 40\ub0S) there seem to be regional anomaly patterns in connection with precipitation occurrence substantially different, and perhaps independent from an orthogonal technique point of view, from those occurring to the south. This influence may affect the hydrological environment and the runoff of cordillera rivers. So, this work addresses a climatologic diagnosis study of circulation patterns linking mid-tropospheric dynamics, cyclonicity and anticyclonicity conditions, and wavetrain pattern of anomalies to the local precipitation and in what a way these patterns are evidenced as significantly different with latitude affecting different runoff regimes. These atmospheric patterns are responsible of precipitation production, both liquid and solid, which feeds and controls the cordillera rivers. Consequently, depending on what hemispheric and large-scale factors are acting this would affect or favour a determined anomaly pattern associated which in turn is associated with precipitation at a given locality, and, hence, the runoff variability.Pages: 1969-197
