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Article Type:
Research Article

Environment Associated with Deep Moist Convection under SALLJ Conditions: A Case Study

Paloma Borque Departamento de Ciencias de la Atmósfera y los Océanos, FCEN, University of Buenos Aires, Buenos Aires, Argentina

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Paola Salio Departamento de Ciencias de la Atmósfera y los Océanos, FCEN, and Centro de Investigaciones del Mar y la Atmósfera, CONICET, University of Buenos Aires, Buenos Aires, Argentina

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Matilde Nicolini Departamento de Ciencias de la Atmósfera y los Océanos, FCEN, and Centro de Investigaciones del Mar y la Atmósfera, CONICET, University of Buenos Aires, Buenos Aires, Argentina

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Yanina García Skabar National Weather Service, and Facultad de Agronomía, University of Buenos Aires, Buenos Aires, Argentina

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Print Publication:
01 Jun 2010
DOI:
https://doi.org/10.1175/2010WAF2222352.1
Page(s):
970–984
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Abstract

The present work focuses on the study of the environmental conditions preceding the development of a group of subtropical mesoscale convective systems over central and northern Argentina on 6–7 February 2003 during the South American Low Level Jet Experiment. This period was characterized by an extreme northerly low-level flow along the eastern Andes foothills [South American low-level jet (SALLJ)]. The entire studied episode was dominated by the presence of a very unstable air mass over northern Argentina and a frontal zone near 40°S. The SALLJ generated an important destabilization of the atmosphere due to the strong humidity and differential temperature advection. Orography provided an extra lifting motion to the configuration of the regional wind field, which was efficient in forcing the initiation of convection. Once convection developed, it moved and regenerated in regions where the convective instability was horizontally homogeneous and stronger.

* Current affiliation: Department of Atmospheric and Oceanic Sciences, McGill University, Montreal, Quebec, Canada

Corresponding author address: Paloma Borque, Dept. of Atmospheric and Oceanic Sciences, McGill University, 805 Sherbrooke St. W, Montreal, QC H3A 2K6, Canada. Email: paloma.borque@mail.mcgill.ca

Abstract

The present work focuses on the study of the environmental conditions preceding the development of a group of subtropical mesoscale convective systems over central and northern Argentina on 6–7 February 2003 during the South American Low Level Jet Experiment. This period was characterized by an extreme northerly low-level flow along the eastern Andes foothills [South American low-level jet (SALLJ)]. The entire studied episode was dominated by the presence of a very unstable air mass over northern Argentina and a frontal zone near 40°S. The SALLJ generated an important destabilization of the atmosphere due to the strong humidity and differential temperature advection. Orography provided an extra lifting motion to the configuration of the regional wind field, which was efficient in forcing the initiation of convection. Once convection developed, it moved and regenerated in regions where the convective instability was horizontally homogeneous and stronger.

* Current affiliation: Department of Atmospheric and Oceanic Sciences, McGill University, Montreal, Quebec, Canada

Corresponding author address: Paloma Borque, Dept. of Atmospheric and Oceanic Sciences, McGill University, 805 Sherbrooke St. W, Montreal, QC H3A 2K6, Canada. Email: paloma.borque@mail.mcgill.ca

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