Analyzing the Results
trusting the forecast project

Analyzing the Data:
Compare your forecasted values for each day with the actual observations to determine how accurate your forecasts were. For each temperature value, determine the difference between the forecasted value and observed value.

Your forecasted temperature: 56
Observed temperature: 62
Error: 6 degrees

Accuracy of Temperature Forecasts:
Calculate the average error in your temperature forecasts by summing up all the differences and dividing by the total number of temperature forecasts made.

Avg Error = (sum of degrees error) / (total days forecasted)

Accuracy of Precipitation Forecasts:
For analyzing the precipitation forecasts, how many days did you make a correct forecast? Compute your percentage of accuracy by dividing the number of correct precipitation forecasts by the total number of forecasts made.

% accuracy = { (number of correct forecasts) / (total forecasts) } *100%

Comparing Day 1 Forecasts with Day 2:
Perform the same calculations described above, but separately for day 1 and separately for day 2.

- Was there a difference in accuracy between day 1 forecasts and day 2?
- Was there a greater error in temperature forecasts for day 2 values when compared with day 1?
- Were the precipitation forecasts more accurate for day 1 than for day 2?
- Use the calculated numbers to back up your results.

Why Were There Errors in Predicting Weather Conditions?:
During what types of weather conditions were your forecasts most accurate? During which weather conditions did your values have the greatest margins of error? When answering these questions, consult the observations you took for each day that was forecasted. Consider factors like:

- Cloud Cover
- Winds
- Dew point temperatures
- Plus consider features like low pressure centers
- Fronts
- Or other weather features that may have played a role in your missed forecasts.

Final Analysis:
Here are some final questions to consider:

- What scaffolding activities did you complete?
- Did you show improved accuracy in your forecasts after completing these activities?
- Describe a situation in which you used the knowledge gained from these activities to improve your forecast.
- What issues did you learn about weather forecasting that you did not know before hand?

culminating project
Terms for using data resources. CD-ROM available.
Credits and Acknowledgments for WW2010.
Department of Atmospheric Sciences (DAS) at
the University of Illinois at Urbana-Champaign.