1. A Thunderstorm Nowcasting System for the Beijing 2008 Olympics: A U.S./China Collaboration by James Wilson 1 and Mingxuan Chen 2 1. National Center for Atmospheric Research, Boulder, CO 80307-3000 2. Institute of Urban Meteorology, CMA, Beijing 100089

2. OUTLINE Olympics 2008 support and B08FDP Beijing Auto-Nowcast system Climatology Important local considerations Plan

3. Convective storms frequent Beijing area For supporting 2008 Olympics, BMB and NCAR are conducting a joint project on convective storm nowcasting that is implementation and further development of ANC at BMB

4. Beijing 2008 Forecast Demonstration Project ( B08FDP, http://www.b08fdp.org/ ) sanctioned by the WMO World Weather Research Program Beijing 2008 Forecast Demonstration Project ( B08FDP, http://www.b08fdp.org/ ) sanctioned by the WMO World Weather Research Program Objective - Test state-of-the-art very short period forecasting systems Objective - Test state-of-the-art very short period forecasting systems Participants: China/U.S. – Beijing Auto-Nowcast China - GRAPES Hong Kong – SWIRLS Canada – CARDS Canada/U.S. – MAPLE U.S. – Niwot U.S./Australia – RTFV Australia – STEPS, TIFS

5. 600 km 200 km B08FDP Forecast and Verification Domain ~ 4 radars (S-band & C-band) ~ 100 surface stations (AWS) ~ 3 profilers ~ 14 GPS/Met Satellite (FY-2C & MTSAT) ~ 3 radiosondes (4 times/day in Aug) Meso-NWP

6. OUTLINE Olympics 2008 and B08FDP Beijing Auto-Nowcast system Climatology Important local considerations Plan

7. Data Sets Radar Satellite Mesonet Profiler Sounding Numerical Model Lightning Analysis Algorithms Predictor Fields Forecaster Input Fuzzy Logic Algorithm - Membership functions - weights - Combined likelihood field Final Prediction Beijing Auto-Nowcast System

8. Produces 0-1 hr time and place specific forecast Expert system utilizes fuzzy logic Ingest multiple data sets Ingest Meso-NWP outputs Beijing Auto-Nowcast System 4-D Variational Doppler Radar Analysis System (VDRAS) Extrapolates radar echoes Forecast storm initiation, growth and dissipation Algorithms derive forecast parameters based on the characteristics of the boundary- layer, storms, and clouds

9. Example of Auto-Nowcast 60-min Initiation Forecast 1 hour forecastVerification Initiation nowcasts Extrapolation nowcasts

10. OUTLINE Olympics 2008 and B08FDP Beijing Auto-Nowcast system Climatology Important local considerations Plan

11. Distribution of storm initiation or appearance location over Beijing area Based on 2003~2005 data from Beijing C- band radar (77 cases and > 30 dBZ) Conclusion: Most (77%) of those come from a westerly direction 6 ％ of total 17 ％ of total 4 cases north 77 ％ of total 2 cases south 28 cases northwest 9 cases northeast 20 cases southwest 3 cases southeast 11 cases west

12. 28(10) 20(7) 11(4) 9(7) 4(2) 3(2) 2(1) 2(2) 0 Origin of storms (>30 dBZ) that arrive in or initiate in Beijing area Based on 2003~2005 data from Beijing C-band radar (79 cases and > 30 dBZ) inside bracket number storms initiatiated in Beijing Conclusions: 57% move in and 43% initiate 28% of those that move in enhance

13. OUTLINE Olympics 2008 and B08FDP Beijing Auto-Nowcast system Climatology Important local considerations Plan

14. Important local considerations for the Beijing Auto-nowcast system Terrain and southeast winds Convection initiation along convergence lines Sea breeze influences Dissipation or enhancement as storms move from mountains to plains Dissipation of storms when convergence line moves away

15. Example 1: Terrain influence with southeast low-level flow

17. Example 2: Squall line dissipation moving from mountain to plains Click to start or pause animation

18. Example 3: Squall line enhancement moving from mountain to plains Click to start or pause animation

19. Example 5: Boundary running away from storm and dissipating Click to start or pause animation

20. Example 6: Initiation and enhancement of storms when boundaries interact and storms move from mountains to plain/urban areas

22. Click to start or pause animation

23. OUTLINE Olympics 2008 and B08FDP Beijing Auto-Nowcast system Climatology Important local considerations Plan

24. Ingesting of new local data (Zhangbei C-band radar, AWS surrounding Beijing, FY-2C, profiler, etc.) Further development and improvement of the nowcast system Rerun some 2006 cases Tune parameters and memberships Add some new algorithms Radar climatology study Trial demonstration summer 2007 Formal FDP in 2008 Plan

25. Thank you for your attention!

26. Example 4: Storm initiation by convergence lines, rolls also play role Click to start or pause animation

27. Example 6: Initiation and enhancement of storms when boundaries interact and storms move from mountains to plain/urban areas

28. Three S-band Radar Mosaic (Beijing, Tianjin and Shijiazhuang) 06/27/2006 1820UTC

29. Diurnal Cycle based on Tianjin radar Minimum over Beijing 1-2 a.m. local Echo Frequency >35 dBZ Maximum 6-7 p.m. local

30. 30min fcst (08/01/2006 0916UTC) 60min fcst (08/01/2006 0844UTC) Ref (08/01/2006 0947UTC) growth steady decay initiation

31. Cold vortex Trough Subtropical high Jun AugJul The monthly number of related synoptic system with storms

32. The percent of related steering wind with storms 500 mb850 mb700 mbNo data

33. Frequency distribution of convective weather phenomena in Beijing area Based on surface observations in 5-9 month of 12 years (1994-2005) Total Thunderstorm Rainstorm hailstormGale

34. Cold vortex Trough Subtropical high The percent of related synoptic system with storms