The 9-10 November 2001 Algerian Flood. A Numerical Study

This study has found that the Algerian flood of 9-10 November 2001 resulted from convective coupling of an anomalously strong upper-level tropopause fold (and an associated strong IPV anomaly) with surface air warmed by WISHE over the warm southern waters of the Mediterranean Sea. This diff ers from classic Eady wave development not only because of the role of WISHE, but also because of the role of moist coupling of the surface with the upper-level wave via deep moist convection. This "conditional coupling" can lead to a more catastrophic, smaller-scale, and unusually rapid and intense cyclogenesis than one generally expects from more continuous and neutral dry vertical coupling. When occurring in the presence of a particularly strong upper-level IPV anomaly, the results can be devastating.