1143 Seasonal Predictability of Extratropical Cyclone Statistics in the Canadian Seasonal to Interannual Prediction System (CanSIPS)

Wednesday, 25 January 2017
Norman James Shippee, Pacific Climate Impacts Consortium, Victoria, BC, Canada; and C. Seiler and F. W. Zwiers

 Extratropical cyclones have the potential to generate high-impact weather in the mid- and high-latitudes in the Northern Hemisphere. As such, the seasonal predictability of extratropical cyclone statistics and storm tracks within the Northern Hemisphere is of great interest. In this study, the seasonal predictability of Northern Hemisphere fall (Sep-Oct-Nov) and winter (Dec-Jan-Feb) season extratropical cyclones statistics has been investigated using storm tracks calculated from the two-model, 20-member ensemble of the Canadian Centre for Climate Modelling and Analysis (CCCma) Canadian Seasonal to Interannual Prediction System (CanSIPS) over the hindcast period of 1980 – 2009. To calculate storm track statistics, an objective-feature identification and tracking algorithm was applied to each of the ensemble member 850 hPa vorticity fields, and compared to storm track statistics derived from the ERA-Interim reanalysis over the same period. Differences in the mean track density (TDEN), cyclogenesis density (GDEN), cyclolysis density (LDEN) between the seasonal forecasting system and the ERA-Interim baseline will be shown. Additionally, the predictability of storm track statistics at various forecast lead times will be shown, along with the relationship to major teleconnection patterns such as El Niño – Southern Oscillation (ENSO).
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