1. Forecast system development activities

2. Focus Improvement of the IRI Net Assessment
Large-scale, global information
Seasonal averages of temperature and precipitation

3. Net Assessment: precipitation

4. Net Assessment: temperature

5. Current activities Pattern-based correction of model output.
Correct systematic errors.
Calibration based on historical forecasts.
Observed SST vs. forecast SST.
Information beyond terciles
Climatology and forecast probability density functions.
New methods for weighting models.

6. NDJ temperature variability patterns (EOFs)
Model
Obs.
MOS 1 2

7. correlation
Model
MOS

8. Beyond terciles
Near-Normal
Below Normal
Above Normal
Historical distribution
(climatological distribution)
(33.3%, 33.3%, 33.3%)
FREQUENCY
Forecast distribution
(15%, 32%, 53%)
The uncertainty can be expressed (quantitatively) in a number of ways:
1) Probabilities of discrete events
Confidence level is varied.
Interval length is fixed.
2) Error bars / confidence intervals
Confidence level is fixed.
Interval length is varied.
3) Probability distribution on a continuous scale
Breakpoints of categories are determined by historical observations. The probabilities of this distribution are the climatological probabilities.
Forecast distribution (say of the ensemble members at a point, or over a region) represent a shift in the range of possibilities. Now categorical probabilities are not equal – they differ from climatology.
NORMALIZED RAINFALL
Tercile probabilities provide a limited description of the forecast distribution
Users may require other properties of the forecast distribution.

9. DJF(Nov) t2m -- counting

10. Example 1991

11. DJF(Nov) t2m -- Bayesian

12. DJF(Nov) t2m – pattern “CPT”

13. DJF(Nov) t2m – pattern “honest”

14. Example 1991

15. DJF(Nov) t2m – pattern “new”

16. Example 1991

17. Flexible format map room

18. Flexible format map room

19. Parametric pdfs Gaussian for seasonal temperature
Power transformed Gaussian (Box-Cox) for seasonal precipitation

20. No skew

21. Some skew

22. More skew

23. Future work Add precipitation forecasts to flexible map room.
Improved multi-model weights
NOAA funded proposal with COLA/GMU and CPC.