360 likes | 583 Views
Monthly and Seasonal forecasts Laura Ferranti and the Seasonal Forecast Section. User meeting 14-16 June 2006. Outline:. Monthly Forecast: Performance Verification information is available on web - New products are made available on the web Seasonal forecast:
E N D
Monthly and Seasonal forecastsLaura Ferranti and the Seasonal Forecast Section User meeting 14-16 June 2006
Outline: • Monthly Forecast: • Performance • Verification information is available on web • - New products are made available on the web • Seasonal forecast: • - Performance • - EUROSIP multi-model products in progress • - S3 verification/documentation in progress
Performance over the Northern Extra-tropics ROC area of probability of 2-meter temperature in upper tercile Monthly Forecast Monthly Forecast Persistence of day 5-11 Persistence of day 5-18 Day 12-18 Day 19-32
Examples of verification Example of probabilistic scores: ROC Map
Precipitation over India 08/05-15/05 15/05-22/05 22/05-29/05 29/05-05/06 An. Day 5-11 Day 12-18
Indian monsoon Probability of precipitation in the upper tercile 27 real-time cases covering the period May-June-July-August 2002, 2003, 2004 , 2005 Monthly Forecast Persistence of the probabilities of the previous week DAY 19-25 DAY 26-32 DAY 12-18 ROC score: 0.580.49 ROC score: 0.460.48 ROC score: 0.640.49
Precipitation over Africa 08/05-15/05 15/05-22/05 22/05-29/05 29/05-05/06 An. Day 5-11 Day 12-18
African monsoon Probability of precipitation in the upper tercile 27 real-time cases covering the period May-June-July-August 2002, 2003, 2004 and 2005 Monthly Forecast 20W-25E, 0N-20N Persistence of the probabilities of the previous week DAY 12-18 DAY 19-25 DAY 26-32 ROC score: 0.590.54 ROC score: 0.540.49 ROC score: 0.530.49
MJO real-time forecast Indian Ocean West. Hemis And Africa Maritime continent western Pacific
MJO real-time forecast Stamp map of velocity potential at 200 hPa
Seasonal forecasting of tropical storms Forecasts starting on 1st June 2005: JASON ECMWF OBS: JJASON 2005 EUROSIP WNP ENP Atl
Seasonal forecasting of tropical storms 1993-2005Forecasts issued in June ECMWF: corr 0.70 EUROSIP: corr 0.75
EUROSIP: Forecast start May 2005 Observed anomalies SST: JJA 2005
Past performance (i): GPCP anomaly JJA 2005
Forecast started Nov 2005: EUROSIP predictions for DJF 2006 over Europe: observed anomaly: mslp Prob (mslp > median) Prob (2m temp > median) 2m temp
Forecast started Nov 2005: observed anomaly: Ecmwf predictions for DJF 2006 over Europe: mslp Prob (mslp < median) Prob (2m temp > median) 2m temp
Skill comparison: S2 vs S3: S3 Operational (S2) Persistence
Summary (1): Monthly Forecast: • Good performance over the Northern extra-tropics up to 19-32 days. • Good skill in predicting the Indian monsoon. • Prediction of the West African monsoon show less skill. • Verification is on the website and it is updated every week. • Additional products are made available on the web.
Summary (2): Seasonal Forecast: • Good performance for the predictions of SST anomalies over the equatorial Pacific. • Tropical storm predictions show a good skill and this is enhanced by the EUROSIP multi-model system. • Neither the ECMWF or EUROSIP dynamical systems produced good predictions for the last winter (DJF 2005/06). • The skill of the seasonal forecast varies with regions and seasons. • Latest results from S3 indicate that the Niño predictions are generally improved.
Past performance: Guinea Coast precipitation from May 2005 forecasts Ecmwf Météo France Met Office
Ecmwf SST DJF 2006 Météo France Met Office
2m temp predictions for DJF 2006: i.c. Nov 05 ECMWF Météo France Observed anomalies Met Office
mslp predictions for DJF 2006: i.c. Nov 05 ECMWF Observed anomalies Météo France Met Office
Predictions of 2m temp anomalies over Southern Europe: Météo France Ecmwf Met Office
NAO Predictions : Météo France Ecmwf Met Office
DJF Correlation between:2m temp over (0-35E,10-30N) and Z 500hPa (1987-2003) Era 40 Met Office Ecmwf
DJF Correlation between: 2m temp over (0-35E,10-30N) SST (1987-2003) Era 40 Met Office Ecmwf
Tropical Storms: Monthly ForecastProbability of a tropical storm within 1 degree Day 10-32 Forecast starting on 4 August 2005 Model climatology starting on 4 July 1993-2004
Cy 29r1 System 3 experimentation:10m zonal wind bias Too weak easterlies Cy 29r3 Oper. system MJJ (1987-2003) m 2-4