Subseasonal forecasting for Africa and tropical climate ... · PDF fileSubseasonal forecasting...
Transcript of Subseasonal forecasting for Africa and tropical climate ... · PDF fileSubseasonal forecasting...
Subseasonal forecasting for Africa and tropical climate sensitive regions
Wassila M. Thiaw
Climate Prediction CenterNational Centers for Environmental Predictions
International TeamEndalkachew BekeleTom DiLibertoVadlamani KumarNicholas NovellaChalump OonariyaMiliaritiana Robjhon Acknowledgements: CFS Team, NMME Team
• Climate monitoring
• NWP tools – severe weather up to one week
• Subseasonal outlooks (week1, week2, week3, week4, monthly)
• Seasonal outlooks
Hazards Outlooks Basic Requirements
Approach to operational subseasonal forecasting
• Assess state of the MJO and forecasts– MJO active and projected to remain active
• MJO rainfall anomaly composites & NWP toolsGuidance to draw polygons of enhanced or suppressed
rainfall
Phase 4, 90% CI Phase 8, 90% CI
Phase 1, 90% CI Phase 5, 90% CI
MJO rainfall anomaly compositeMaritime Continent, DJF
NE Brazil, DJF
Phase 1, 90% CI Phase 5, 90% CI
Phase 1, 90% CI Phase 5, 90% CI
West Africa, JAS
East Africa, OND
MJO rainfall anomaly composite
Approach to operational subseasonal forecasting
• Assess state of the MJO and forecasts– MJO active and projected to remain active
• MJO rainfall anomaly composites & NWP toolsGuidance to draw polygons of enhanced or suppressed
rainfall
• NWP tools out to two weeks– Low and upper level winds– Low and mid‐level geopotential height– Mean sea level pressure – Ensemble precipitation forecasts
• Probability of exceedence• Bias corrected precipitation anomaly forecasts
Approach to operational subseasonal forecasting
• Assess state of the MJO and forecasts– MJO active and projected to remain active
• MJO rainfall anomaly composites & NWP toolsGuidance to draw polygons of enhanced or suppressed
rainfall
• NWP tools out to two weeks– Low and upper level winds– Low and mid‐level geopotential height– Mean sea level pressure – Ensemble precipitation forecasts
• Probability of exceedence• Bias corrected precipitation anomaly forecasts
• SST anomaly and SST tendency
Data•CFSv2 – 45 day hindcasts•NMME outputs, zero lead•TRMM
Methodology•Construct CFSv2 week1 to week4 P anomaly forecasts•Apply bias correction to the weekly forecasts•Obtain monthly CFSv2 forecasts•Calculate AC between forecasts and observations•Apply CCA correction to NMME forecasts•Evaluate NMME skill
CFS2 and NMME Subseasonal Forecast Skill
Week-1, with BC Week-2, with BC
Week-3, with BC
CFS2 Precipitation (bias corrected) forecast skill
Week-4, with BC