1. SASCOF 2010 Météo-France GCM forecasts JP. Céron – Météo-France Jean-Pierre.Ceron@meteo.fr

2. Outline Météo-France forecasting suite SSTs Seasonal Forecasts General Circulation Forecasts Rainfall Seasonal Forecasts Summary

3. The Meteo-France Operationnal Suite « Mercator » version of Arpège (v 4) : Toulouse Reading DClim Météo-France WMO Global Bulletin Users Euro-SIP (Multi-Models)

4. The Meteo-France Operationnal Suite Coupled Model version 3 Atmosphere : Arpege 4.4, t63l91 (same levels than ECMWF analysis), Ocean : OPA & Orca grid (31 vertical levels ~10m close to the surface and ~500 m below 3000 m, 2° resolution with 0.5° meridional resolution in the tropics), Coupling : Oasis v2.4, Mercator reanalysis : 1979 – 2007, new assimilation scheme using insitu data and altimetry, Hindcast : over the 1979-2007 period, 11 members, 7 month range run, Operationnal : 41 membres, 7 month range run, Availability : end of the year, beginning of 2008

5. Outline Météo-France forecasting suite SSTs Seasonal Forecasts General Circulation Forecasts Rainfall Seasonal Forecasts Summary

6. SSTs Seasonal Forecast – Global MJJ 2010 SST anomaly (ensemble mean)

7. SSTs Seasonal Forecast – JJA & JAS Global SST anomaly (ensemble mean)

8. SSTs Seasonal Forecast Niño3.4 Pacific : Niño boxes

9. SSTs Seasonal Forecast Indian Ocean : OOPC boxes

10. Recap SSTs Seasonal Forecast Pacific : evolution toward colder condition in the Central and Eastern Pacific La Niña event later ? Indian Ocean : Quite warm conditions everywhere (notably in Western part) DMI close to neutral Good stability of the SST forecast over the MJJ to JAS period

11. Outline Météo-France forecasting suite SSTs Seasonal Forecasts General Circulation Forecasts Rainfall Seasonal Forecasts Summary

12. Probabilistic forecasts for MJJ 2010 General Circulation Stream Function 200hPa Velocity Potential 200hPa Khi200 JJA Khi200 JAS Consistent signal leading to less favourable convective conditions on the half northern part of India and South-East Asia Monsoon onset delayed (notably in North India) ?

13. Probabilistic forecasts for MJJ 2010 General Circulation V 850hPa U 850hPa Circulation in the low troposphere Zonal circulation weakened in the South Hemisphere (Indian Ocean) and strengthenned in the Northern hemisphere (East IO and Pacific) Meridional circulation strengthenned (West IO)

14. Outline Météo-France forecasting suite SSTs Seasonal Forecasts General Circulation Forecasts Rainfall Seasonal Forecasts Summary

15. Probabilistic forecasts of precipitation MJJ – JJA – JAS 2010 MJJJJA JAS Indian region : Rainfall enhanced on the southern part (GCM discrepancy ?) South-East Asia : Rainfall enhanced notably in JJA

16. Probability of extreme rainfall scenarios MJJ – JJA – JAS 2010 MJJJJAJAS Below – 1 std Above + 1 std

17. Summary. The forecast for the MJJ 2010 indicates : - an evolution toward cold SST anomalies over the Equatorial tropical Pacific (which should persists during all the summer season) - a relatively warm SST over the Indian Ocean (notably Western part) for all the summer season - Above normal Rainfall in the southern part of the Indian continent and in South-East Asia. Enhanced probability of “extreme” rainfall scenario over these regions - Indian monsoon onset possibly delayed in the Northern part

18. The Meteo-France Operationnal Suite

19. Probabilistic forecasts of T2m MJJ – JJA – JAS 2010 MJJJJA JAS Indian region : T2m warmer than normal notably on West cost and Northern part of India South-East Asia : T2m above normal in MJJ

20. SST ROC skill : MJJ tercile categories Fcst prob.Skill (1987-2001) Fcst prob.Skill (1987-2001) outer-quintile categories Lower TercileUpper Tercile

21. Rainfall ROC skill : MJJ tercile categories Fcst prob.Skill (1987-2001) Fcst prob.Skill (1987-2001) outer-quintile categories Lower TercileUpper Tercile

22. T2m ROC skill : MJJ tercile categories Fcst prob.Skill (1987-2001) Fcst prob.Skill (1987-2001) outer-quintile categories Lower TercileUpper Tercile