The storm of October 21-22, 1994, over Greece: Observations and model results

During October 21, 1994, a cold front passed over Greece. This frontal passage provoked catastrophic floods and there were many casualties. Eleven deaths were reported during this event, nine of them inside the Greater Athens Area. Significant damages occurred in transportation telecommunication and energy supply networks, especially in the eastern part of the country. This paper reports on the simulations of the observed storm conducted by two numerical models: the Colorado State University-Regional Atmospheric Modelling System (CSU-RAMS) and the eta-eta/National Meteorological Center (ETA/NMC) model. The intercomparison of results between a regional research-oriented model (RAMS) with an operational model (ETA/NMC) permitted to explore the capabilities and limitations of each one of them. RAMS was operated in a nonhydrostatic made using explicit microphysics and grid nesting (two nests with 40- and 10-km horizontal grid interval) and provided results which compare favorably with observations, suggesting that the model can adequately represent the mesoscale structure of the system. ETA/NMC is a hydrostatic limited-area model using parameterization of large-scale and convective precipitation. It was operated with 25-km horizontal resolution and it forecasted successfully the major characteristics of the system but failed in reproducing quantitatively the precipitation pattern at the mesoscale.