Laurence Wilson Associate Scientist Emeritus Environment Canada Monica Bailey, Marcel Vallee and Ivan Heckmann Verification of forecasts from the 2010 Vancouver Olympic Games

Outline Data Available Observations Forecasts Verification plan Preliminary Results Future

Observing sites in the vicinity of Whistler -supplementary obs sites (VOA, VOL etc) -extra in situ instrumentation -radars -profilers

“Standard” stations for verification

Forecasts GEM-15 km regional model 2.5 km LAM using bc from regional model 1 km LAM nested in 2.5 km model No data assimilation for LAMs Several nowcast and post-processing systems: –Adaptive blending of observations and models (ABOM), INTW –CMA, ZAMG-INCA, NCAR-WSDDM Limited UMOS for Olympic sites Operational forecasts for Olympic venues 15 km 1 km 2.5 kmWhistlerVancouver

Snowboard Men’s Parallel Giant Slalom Final February 27, 2010 Gold Medal to Jassey Jay Anderson of Canada Snowboard spectators stand in the fog during the men's Parallel Giant Slalom snowboarding competition at the Vancouver 2010 Olympics in Vancouver, British Columbia, Saturday, Feb. 27, (AP Photo/Bela Szandelszky)

Visibility forecasts and obs before mens giant snowboard slalom finals

Snow- V 10 Verification plan At least two classes of users: Olympics forecasting team – VANOC “ How accurate are forecasts of weather events significant to VANOC? ” “ Should the forecasters have used the nowcast products? ” Modelers “ Are forecasts from the 2.5 km LAM an improvement on the 15km regional forecasts? ” “ Are there any advantages to the 1 km grid? ” Two Parts: user-oriented verification for Olympic period of all forecasts, tuned to decision points of VANOC Verification of parallel model forecasts for Jan to August 2010 Rich dataset for user-oriented verification and research: multiple observations at some sites, allows for estimates of observation error

Verification strategy User-specified thresholds – categorical/contingency tables Only surface-defined variables For user-oriented verification: Wind, precipitation amount and type, visibility, wind gusts, cloud base height, temperature, humidity High temporal resolution – 15 minutes 0-2h, hourly after that During Olympics period only « representative » point selected in advance by forecasters For Model verification: Temperature, precipitation, wind, cloud amount, and possibly ceiling and visibility From all stations in model domain 6 months period At stations, categorical and continuous verification

Suggested Categories for SNOW-V10 Analysis

Standardized forecast table for Vancouver Olympics

Preliminary Comparison of Sport Forecast with Canadian Models for Top of Downhill (VOA), Mid- Station (VOL) and Timing Flats (VOT) Wind Direction

Bias for temperature forecasts

RMSE, T2m, 6 mo, all stns in model domain

Future Finish verification according to plan based on “standard” data Special journal issue planned Comparison with operational forecasts Verification using “special” data Higher temporal resolution Research studies: Estimating observation error Model diagnostic studies