Sunday, 22 January 2012
Characteristics of Warm-Season Persistent Elongated Convective Systems in Subtropical South America
Hall E (New Orleans Convention Center )
This study investigates the properties of persistent elongated convective systems (PECS) in subtropical South America (SSA) during the warm seasons of 1998-2007. PECS, which are similar to the more commonly studied subset of mesoscale convective systems called mesoscale convective complexes (MCCs) in every way except they are not quasi-circular at the time of their maximum extent, are found to outnumber MCCs 1287 to 330 for the entire study period. PECS are also found to be larger on average and last longer than MCCs. PECS are nocturnal events that occur most frequently in southern Paraguay, far southern Brazil, and far northern Argentina and are most common in the month of January. PECS tend to be larger and longer-lasting near the beginning and end of the warm season, with minimums in size and duration during the middle of the warm season. A moderate correlation between maximum area of PECS cloud shields and their duration was found, suggesting that larger PECS tend to last longer. Initial results suggest a tendency for PECS to form along the eastern slopes of the Andes Mountains and track northeastward, but further analysis must be conducted to determine the favored patterns of PECS movement in the region.