Advances in Geosciences www.adv-geosci.net 1680-7340 1680-7359 23 10th EGU Plinius Conference on Mediterranean Storms (2008) 2010 10.5194/adgeo-23-25-2010 http://www.adv-geosci.net/23/25/2010/ http://www.adv-geosci.net/23/25/2010/adgeo-23-25-2010.html http://www.adv-geosci.net/23/25/2010/adgeo-23-25-2010.pdf 25 30 2010-03-08 Operational forecasting of a snowfall event over the Greater Athens Area P. Louka louka@hnms.gr D. Boucouvala F. Gofa M. Balami D. Ziakopoulos Hellenic National Meteorological Service, El. Venizelou 14, Hellinikon, 16777, Greece A case of an intense snowfall in the Greater Athens Area (GAA) between 16 and 18 February 2008 is investigated. The physical processes that forced the snowfall event are identified and analysed. The main factor causing the event at its start was the entrainment of arctic air masses from North-Eastern Europe. At a second stage, the Aegean Sea acted as the Great Lakes of Canada and North-East USA and in association with the existing extremely cold air masses aloft and the enrichment of the air with humidity and heat led to the enhancement of the snowfall in the GAA. In the final stage of the event, the local meteorological conditions associated with the topography of the area resulted in the occurrence of very intense snowfall event on the leeward side of the GAA. The available operational observations and forecast tools were used for accurately predicting the intensity, duration and evolution of the event. Doms, G., Förstner, J., Heise, E., Herzog, H.-J., Raschendorfer, M., Reinhardt, T., Ritter, B., Schrodin, R., Schulz, J.-P., and Vogel, G.: A description of the nonhydrostatic regional model~LM – Part~II Physical parameterisation, available at: http://www.cosmo-model.org/content/model/documentation/core/, 2007. Kallos, G., Nickovic, S., Papadopoulos, A., Jovic, D., Kakaliagou, O., Misirlis, N., Boukas, L., Mimikou, N., Sakellaridis, G., Papageorgiou, J., Anadranistakis, E., and Manousakis, M.: The regional weather forecasting system SKIRON: an overview, Proceedings of the International Symposium on Regional Weather Prediction on Parallel Computer Environments, 15–17~October~1997, Athens, Greece, 109–122, 1997. Lagouvardos, K., Kotroni, V., Fragouli, P., Ziakopoulos, D., and Anadranistakis, M. : The 4–6~January~2002 snowfall: Analysis of the forecast skill of limited area numerical models, Proceedings 6th~Hellenic conference on Meteorology, Climatology and Atmospheric Physics, Ioannina 25–28~September, 2002. Niziol, T. A.: Operational forecasting of lake effect snowfall in western and central New York, Weather Forecast., 2, 310–321, 1984. Pielke, R. A., Cotton, W. R., Walko, C. J., Tremback, C. J., Lyons, W. A., Grasso, L. D., Nicholls, M. E., Moran, M. D., Wesley, D. A., Lee, T. J., and Copeland, J. H.: A comprehensive meteorological modeling system – RAMS, Meteorol. Atmos. Phys., 49, 69–91, 1992. Prezerakos, N. and Angouridakis, V.: Synoptic consideration of snowfall in Athens, J. Climatol., 4, 269–285, 1984. Steppeler, J., Doms, G., Schättler, U., Bitzer, H.-W., Gassmann, A., Damrath, U., and Gregoric, G.: Meso-gamma scale forecasts using the non-hydrostatic model~LM, Meteorol. Atmos. Phys., 82, 75–96, 2003. Tiedtke, M.: A comprehensive mass flux scheme for cumulus parameterization in large-scale models, Mon. Weather Rev., 117, 1779–1799, 1989.