Portal de Periódicos da CAPES

Interaction of an Intense Pacific Low Pressure System with a Strong Arctic Outbreak over British Columbia: Forecast Challenges of the Early December 2007 Storm

2012; Taylor & Francis; Volume: 50; Issue: 1 Linguagem: Inglês

10.1080/07055900.2012.656261

1488-7576

Quanzhen Geng, Ruping Mo, Mindy Brugman, Brad Snyder, Jim Goosen, G. S. Pearce,

Atmospheric and Environmental Gas Dynamics

The interaction of a warm moist air mass from an intense Pacific low pressure system with a cold air mass from a strong Arctic outbreak during 1–5 December 2007 produced a record number of high-impact weather events across British Columbia, including heavy snow, freezing rain, heavy rain, strong winds and extreme wind chill. The unusual concurrence of these two strong weather systems caused many forecast challenges for both the Canadian numerical weather prediction (NWP) models and meteorologists at the Pacific Storm Prediction Centre (PSPC) of Environment Canada. In this study, the evolution of the weather systems and the observed severe weather events during the 1–5 December 2007 storm are analyzed. Weather forecasts by the NWP models and PSPC meteorologists are compared with the observed high-impact weather events. It is shown that the Canadian NWP models forecast the storm reasonably well. Meteorologists at PSPC further improved the model forecasts by considering various local effects of the complex terrain over British Columbia that the model has difficulty resolving and model biases caused by inadequacies in its boundary layer parameterizations.