Probabilistic Forecasting Software Application Information

Ensemble Weights

The Ensemble Weights tool displays grids of statistics interactively as the user adjust the weights for various models.  An image of the user interface is displayed below:

Ensemble Weights GUI

Running the tool

Before running the Ensemble Weights tool, load the ensemble members using the WeatherElements->WeatherElementGroups selector. Once the models are loaded, select one of the grids.  Then from the ProbTools menu select EnsembleWeights.  The tool will load the grids (takes about 15 seconds), calculate statistics grids and then displays the interface above.

Each slider correspnds to a different ensemble member.  The name of the model is listed just above each slider.  As you move one of the sliders to the left or right, the statistics grids are recalculated and displable in the GFE.  If you are currently viewing one of these grids you can see grid values change as you move the slider.

Tutorial

The following tutorial will walk you throught the steps of using the EnsembleWeights tool.
  1. Make sure you have the ensemble members loaded into the GFE by using the WeatherElements->WeatherElementGroups menu.  There are several options to load all 21 SREF members at once for each weather element.
  2. Select one of the grids that you loaded into the GFE to define the time range for the tool.
  3. Run the EnsembleWeights tool by selecting from the ProbTools menu: EnsembleWeights.  Wait for the data to load.  When the WeightedMean grid appears in the Grid Manager, display it by clicking it with button one on the mouse.
  4. When the user interface appears, move several of the sliders to zero.  As you move the slider, watch the GFE change with each motion.  You may have to resize the GFE to see both the user interface and the GFE display at the same time.  Note that most of your changes cause the WeightedMean grid to change only slightly.  Each model contributes a little less than 5% of the total mean.
  5. Move all of the sliders to zero except two.  Now move one of the remaining non-zero sliders and watch the GFE display change.  Since only two models are contributing, the changes are more dramatic.