Synoptic and mesoscalar environments associated with the heavy local rainfall on 16 August 2010 in the south of the Iberian Peninsula

Abstract

In this paper we show the synoptic and mesoscale environment aspects associated with a local event of heavy rainfall in the south of the Iberian Peninsula on 16 August 2010, exceeding 200 mm in 5 hours and causing significant flash flooding, by using observational data and operational analyses and forecast data from the European Centre for Medium-Range Weather Forecasts. The event was associated with the poleward transport of deep tropical moisture along the western flank of the upper and middle level summer anticyclone over North Africa, and with a mid-level cyclogenesis caused by the interaction between a middle latitude trough and the tropical moisture band. The cyclogenesis produced an outflow jet streak and the exportation of tropical moisture to the Iberian Peninsula. On the synoptic scale, the heavy precipitation occurred where this tropical moisture intersected a region of forced ascent situated beneath the equatorward jet streak-entrance region. On the mesoscale, the event was focused on a zone of orographic wind convergence.