Some ideas on verification targeted to the use of the forecasters Pierre Eckert, MeteoSwiss, Geneva Some ideas on the presentation to the forecasters of the verification results Francis Schubiger, MeteoSwiss, Models

Forecasters psychology Less models, better verified Quality of model(s) often judged subjectively Verification by order of preference: The temperature std is… The temperature bias in Europe is… The temperature bias in Switzerland is.. The temperature bias of low stations in CH is… The temperature bias of the low stations in Valais is … The temperature bias of the low stations in Valais in SW situations in autumn is…

Stratified verification Verification has to be local (not too much)… …and stratified It can be stratified by type of phenomena (thunderstorms, drizzle,…) either observed or forecasted Or by type of synoptic situation (any classification) These results can be used in order to implement targeted postprocessing… …or be used by the forecasters in order to correct the models, not use them in certain cases, use different indicators from models,… The verification should be relevant to the present version of the model

Work already done Precipitation bias by weather class (Zala) 2008, SW 2008, flat

Work already done Fuzzy verification by weather class (Weusthoff) We think about how to communicate the results

More basic ideas Other parameters than (radar) rainfall should be verified Eckert /Schubiger made a proposition (April 2009) It should be tried out Stratified verification 4 seasons Synoptic classification (Zala, COST 733,…) Temperature (bias, STD) Dew point (bias, STD) Precipitation (Frequency bias, POD, FAR, ETS) Cloudiness, wind speed, wind gusts

Graphical presentation By class on map By station, histogram 2008, sw, summer

Presentation to forecasters Seasonal verification is summarised on the MeteoSwiss Intranet (as it was on the COSMO web for a couple of years) In November 2008 a workshop between forecasters and modellers has been organised in order to improve the two way link between both “worlds” Redaction of “COSMO guidelines for forecasters” Redaction of seasonal factsheets Listing of all forecasters feedback “good /bad cases”, with remarks and proposed actions from the modellers