WMO Workshop on Public Weather Services – Effective Warning Systems David Hui Macao, 18 April 2013

Group exercise Create a check list for effective warning system

Users’ response Real time data Warning strategy & operations Internal training Public education & outreach Business Contingency Plan warnings Dissemination Identify extreme / hazardous weather Know climatology Understand impacts & users’ requirements Set up warning criteria

Considerations when formulating operational warning strategy Tools –Essential vs supporting Value –belated warnings are of little use –early warning with intrinsic flexibility of the system Partners –Understand & work together Pace and Timing –various level to trigger matching actions –time when criteria reached –time that are important for users’ decision making

TC warning system in Hong Kong Standby Signal No. 1 Strong Wind Signal No. 3 No. 8 Gale or Storm Signal Increasing Gale or Storm Signal No. 9 Hurricane Signal No. 10 Average no. of TC affecting Hong Kong: 6.4 / year Warning Purpose: High wind and related impact No. of days with warning effective in 2006:20

Experience during passage of Vicente NO. 10 NO. 8 Hurricane force Gale force

Valued added messages Signa l IssuingCancelling TimeExtract of Messages hh mm dd/mon/yyyy hh mm dd/mon/yyyy 115:4021/Jul/201205:2023/Jul/ :45 LOCAL WINDS ARE EXPECTED TO STRENGTHEN. THE OBSERVATORY WILL ISSUE THE STRONG WIND SIGNAL, NO.3 SHORTLY. 305:2023/Jul/201217:4023/Jul/ :45 THE CHANCE FOR ISSUING THE GALE OR STORM SIGNAL, NO. 8 DURING THE DAY IS NOT HIGH. 11:49 IF VICENTE FURTHER INTENSIFIES OR SPEEDS UP TOWARDS THE COAST OF GUANGDONG, THE OBSERVATORY WILL CONSIDER THE NEED OF ISSUING THE GALE OR STORM SIGNAL NO. 8 AROUND SUNSET. 13:55 LOCAL WINDS ARE EXPECTED TO STRENGTHEN FURTHER. THE OBSERVATORY WILL CONSIDER ISSUING THE GALE OR STORM SIGNAL NO. 8 BETWEEN 5 P.M. AND 8 P.M. 8 NE17:4023/Jul/201223:2023/Jul/2012

Hour of the Day that Respondents Most Likely to Access Weather Information

Warnings must evolve to survive Enhanced Warning System Changing Needs of society Warning System

Evolution of warnings in Hong Kong

Warning Process Monitoring & Review Process Design Process Considering Needs of Society & Stakeholders Decision-making/ Response Process Education & Reaching-out Process Development of an Effective Warning System + Operational Strategy

Warning Process Monitoring & Review Process Design Process Considering Needs of Society & Stakeholders Decision-making/ Response Process Education & Reaching-out Process Development of an Effective Warning System + Operational Strategy

Monitoring & Review Process Forecast Verification  objective score Public Opinion Survey  perception, users’ needs/expectations Focus group  testing new services/products Liaison group  tailor-make products for special users Talks, public lectures  collecting opinion in casual way News reports  immediate public perception

Weather forecast in qualitative terms Mainly cloudy. A few rain patches and squally thunderstorms at first. The temperature will range between 24 and 28 degrees. Moderate east to northeasterly winds, occasionally fresh over offshore waters. Marking schemes for the six weather elements: wind speed, state of sky, precipitation, visibility, maximum temperature and minimum temperature A score was given for each element An aggregate score with weighting characteristics of seasons HKO Objective Verification Scheme

Marking scheme State of sky CategorySunshine duration (in %) Mean cloud amount (in oktas) Overcast Cloudy Mainly cloudy Mainly fine Fine/sunny/clear >

State of sky Marks Sunshine duration (%) cloudy Marking scheme of sunshine duration for the category of cloudy

Different weightings (in %) assigned to different weather elements at different time of the year according to climatology and the relative importance of the elements in the eye of the public WindState of skyPrecipitationVisibilityMax temperatureMin temperature January February March April May June July August September October November December HKO Objective Verification Scheme

The score was in general on the rising trend in line with scientific advancement in weather observations, remote sensing technology, NWP and weather forecasting skills Trend of verification scores