Damaging Downburst Prediction and Detection Algorithm (DDPDA)

Prediction

There are three "rules" which can be turned off or on in the algorithm, based on the environmental conditions and the appropriateness of each rule.  The first two rules are really just switches which turn off/on the display of downburst precursors in the cell table.  They all need a lot of work....
 
  1. SEVCNV is displayed in the cell table if the convergent delta-V exceeds 25 m/s
  2. HICORE is displayed in the cell table if the maximum height of reflectivity core  exceeds 8.0 km
  3. Issue a downburst prediction if this equation (based on a limited version of fuzzy logic) is satisfied:

    4.  
      PRED = (-1.5 x convDV) + (2.0 x MaxCoreHt) + (3.0 x ConvDepth) + (4.0 x CoreDrop)

      If PRED > 58, issue a Moderate Prediction
      If PRED > 70, issue a Severe Prediction

      This equation is based roughly on the weights given in the original algorithm (PHX 1994) and on analysis of 50 cells (10 downburst producers) from 7/15/95 in Wisconsin.

The parameter values used in the equation are from the last 1-2 volume scans (varies by parameter).

We hope to develop a full fuzzy logic rule base by the end of the year to replace our rather simple prediction capabilities.

[Ways to develop the prediction capabilities given a list of possible precursors include neural networks, fuzzy logic, and principle component analysis]
 
[Make histograms of every possible parameter and all combinations for all possible time intervals]

[The "matlab" software package has fuzzy logic development tools]
 


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