| This paper describes the evolution of a mesoscale convective system (MCS)
developed over the Alboran Sea on 7 February 2005, using surface, upper-air
stations, radar and satellite observations, and also data from an
operational numerical model.
The system developed during the night as a small convective storm line in an
environment with slight convective instability, low precipitable water and
strong low-level vertical wind shear near coast. The linear MCS moved
northwards reaching the Spanish coast. Then it remained trapped along the
coast for more than twelve hours, following the coast more than five hundred
kilometres.
The MCS here described had a fundamental orographic character due to: (1)
the generation of a low-level storm inflow parallel to the coast, formed by
blocking of the onshore flow by coastal mountains and (2) the orientation of
both the mesoscale ascent from the sea towards the coastal mountains and the
midlevel rear inflow from the coastal mountains to the sea.
The main motivation of this work was to obtain a better understanding of the
mechanisms relevant to the formation of heavy rainfall episodes occurring at
Spanish Mediterranean coast associated with this kind of stationary or
slowly moving MCSs. |