Abstract : 3N.7
The use of the GEM-2.5km model for forecasting gap winds over Vancouver Island

Bradley Snyder, Neil Mclennan, Chris Emond
Meteorological Service of Canada

In 2005, the Canadian Meteorological Centre (CMC) unveiled the high resolution (2.5km) GEM model (Erfani et al, 2005) for operational use over select regions of Canada. One area of focus was British Columbia, a region where complex terrain poses many challenges for the weather forecaster and the modeller.

In an effort to establish closer ties between the research and forecaster communities, an operational evaluation of the 2.5km GEM was initiated in the spring 2006. A number of phenomena were identified and forecasters performed daily assessments on the quality of the model simulations. One phenomenon, gap winds (locally referred to as “Qualicums”), affect central Vancouver Island. These winds can have major impacts on marine traffic on the east side of the island; wind speeds up 15 m/s are observed while elsewhere in the strait, winds may be light.

Forecaster evaluation of the GEM 2.5km performance with respect to gap winds revealed a probability of detection of near 65% for the summer. These results along with simulations from the model are presented.