END-USER FOCUSED VERIFICATION OF PRECIPITATION NOWCASTS DURING THE SOCHI 2014 WINTER OLYMPICS Larisa Nikitina 1, Suleiman Mostmandy 2, Pertti Nurmi (presenter) 3 1 Aviamettelecom of Roshydromet, Russian Federation, 2 North-west department of Roshydromet, Russian Federation ( 3 Finnish Meteorological Institute, Finland,

NOWCASTING SYSTEMS FOR SOCHI 2014 WINTER OLYMPICS RDP Model–based Pointwise 10 min/6 hours Temperature Humidity Wind direction and speed Precipitation INTW (Env.Canada) FDP Radar –based Pointwise 10 min/1,5 hour Only precipitation (rate and accumulated) CARDS (Env.Canada) FDP Blended (Radar +NWP) Gridded (1km) 10 min/ up to 48 hours Temperature Humidity Wind direction, speed and gusts Precipitation (10 min) INCA (ZAMG, Austria) FDP Radar –based Pointwise 10 min/4 hours Temperature Humidity Wind direction, and speed Precipitation Visibility Ceiling MeteoExpert ( IRAM, Russia) FDP Model–based Pointwise Hourly/up to 48 hours Temperature, Humidity Wind speed, direction and gusts MSLP Joint (Multi-system forecast integration, RHM)

QUICK LOOK AT THE DATA Nowcasting (precipitation accumulation): CARDS – (10 min) from till INCA - (10 min) from till INTW – (10min) from till Stations used in verification: Imeretinka (37095), 6m, precip: Vaisala VRG101 Ski Jump (39040), 630m, precip: OTT Pluvio-2 Biathlon Stadium (39044), 1460 m, precip: OTT Rosa Khutor 3, 2043 m, precip: ARG100 Verification aspects: Point-wise forecast vs. observation Categorical verification Subjective evaluation by forecasters CARDS Visualization INTW Visualization

NOWCASTS Evaluated Subjectively 4 ‐ point scale: 0 – not useful 1 – partly useful 2 – useful 3 ‐ excellent Overall forecasters’ opinion was that the available technologies were very helpful Except: Perhaps too many systems (difficult to absorb in operational setting)

CARDS ( ) Some extremes observed but not forecasted and Some good forecasts: , no precipitation , fcst and obs 3-4mm/h (but not for Imeretinka) Some false alarms

Point forecasts statistics for CARDS

INCA ( – ) Some extremes observed but not forecasted and Some good forecasts: , no precipitation and 16.03, fcst and obs 2-4mm/h (not for RKHU 3)!

Point forecasts statistics for INCA

INTW ( – ) Some events observed but not forecasted and Some good forecasts: , no precipitation and 27.03, fcst and obs 2mm/h (not for RKHU 3)! Some false alarms and 20.03

Point forecasts statistics for INTW

Skill (HSS) for 3 Nowcast Systems : CARDS, INCA, INTW 1.In general, all nowcasts demonstrate relatively good skill. 2.They were considered very useful by forecasters during the Games. 3.CARDS shows best overall scores. 4.Underestimation at some sites but, contradictory: Poor forecasts of intense precipitation (missed events).

LESSONS LEARNED Nowcast problems (all models) : Timing: Time of the start and end of phenomena (precipitation) Precipitation amount in case of weakly developed processes Maximum wind speed Visibility and ceiling Forecasters’ model-related challenges: Number of products is both an advantage and a challenge – with many new products and time for decision-making is strictly limited Degree of model usage depends on the degree of forecasters’ familiarity with models and, therefore, confidence in it (more familiar = more usable) Forecasters (other end-users as well) need time to adapt to new products Forecasting issues during the Olympics Key role of forecasters in: Integration and control of diverse and (sometimes) contradictory model information Decision-making process for the high-impact events !