Long Range Forecast of 2008 South-West Monsoon Rainfall

1. India Meteorological Department Presents Long Range Forecast of 2008 South-West Monsoon Rainfall

2. Long range Forecast Schedule • Mid-APRIL • The first Long Range Forecast of South-west Monsoon season (June – Sept) rainfall over the country as a whole. • Mid-May • Forecast for monsoon onset over Kerala • Last Week of June • Seasonal forecast Update • Forecast for July rainfall for the country as a whole • Forecasts for season (June-Sept) rainfall for 4 broad geographical regions of India, viz. • NW India, NE India, Central India, South Peninsula National Climate Centre

3. April Forecast 5 Parameter Statistical ensemble forecasting system Data up to March June Forecast 6 Parameter Statistical ensemble forecasting system Data up to June Operational Forecasting System National Climate Centre

4. List of predictors

6. 2007 Forecasts

8. New Definition of Rainfall Normal • Excess : Above 110% of LPA ( 16% Prob) • Above Normal: 104-110% of LPA (17% Prob) • Near Normal: 96-104% of LPA(33% Prob) • Below Normal: 90-96% of LPA (16% prob) • Deficient: Below 90% of LPA (17% prob)

9. Long Range Forecast for 2008 South-west Monsoon Season (June –September ) RainfallPress Release -16 April 2008

10. Long Range Forecast of 2008 South-west Monsoon Season (June-September) Rainfall IMD’s operational Long Range Forecast for the 2008 South-west Monsoon season (June-September) is that the rainfall for the country as a whole is likely to be 99% of the Long Period Average (LPA) with a model error of ± 5 %. The long period average over the country as a whole is 89 cm ( based on 1941-1990 data). National Climate Centre

11. IMD’s Dynamical Model Forecasts (experimental) March SST Persisted 10 Initial Conditions 21 – 30 March 2008 Forecasts suggest above normal rainfall over central India an NE India and below normal rainfall over NW India. 2008 All India rainfall is likely to be above its Long period average.

12. Forecast Updates to follow: • Middle of May: • Forecast for monsoon onset over Kerala • Last week of June: • Forecast update for South-west Monsoon season (June-Sept) rainfall over the country as a whole • Forecast for July Rainfall over the country as a whole • Forecast for South-west Monsoon season (June-Sept) rainfall over four geographical regions of India National Climate Centre

13. Thank you

14. 2008 Predictions by Various Climate Prediction Centres

15. La Nina developed by August 2007, persisted till February. But, it weakened during the recent days, as some warming tendency is noticed.

16. In the equatorial upper Pacific Ocean, the colder heat content anomalies have weakened. Warmer water prevails underneath of equatorial Pacific.

17. La Nina Predictions Statistical and dynamical models are predicting La Nina conditions to persist for 3 more months.

18. IRI, USA ECMWF, UK

19. NCEP, USA UK MET OFFICE

21. NCEP, CFS Coupled Dynamical Models are suggesting a warming over the east equatorial Indian Ocean by August/September. This may have a negative impact on Indian monsoon, during the second half of the season, especially in September. JAMSTEC, JAPAN

22. IMPACT OF NEGATIVE INDIAN OCEAN DIPOLE

23. DATA FOR 5 PREDICTORS: LRF 2008

24. DATA FOR 8 PREDICTORS: LRF 2008

25. 2008 Forecast Ensembles

26. ECPC Seasonal Forecast Model (SFM ) Forecasts Model Climatology Difference between two climatologies

27. Comparison of EMR and PPR models with Operational forecasts

29. A New Method For Forecasting All-India Monsoon Rainfall

30. Correlation of predictors with monsoon rainfall North Atlantic Pressure (May) North Atlantic SST (Dec+Jan)

32. South Peninsula Central India

33. Northeast India Northwest India

34. Performance of new method