Methodology

 
  • FORTRAN 90 programs were revised to gather and analyze the snowfall data.
  • The programs computed the following:

    •                Monthly averages
                   Seasonal averages (October-April)
                   Snow Events >= X inches
                   2-Day Snow Event Totals
     
     

    Event Maps

  • The threshold for a significant snowfall event was set at 4-inches.
  • 9-panel plots of sea level pressure, 850 mb heights and temperatures, and 500 mb heights and vorticity were generated for each event meeting or exceeding the threshold using GEMPAK.
  • Plots were generated and analyzed at -24, -12, and 0 hours, of the date of significant snowfall.

    • Composite Maps

     
  • Composite maps were then made from the analyzed data to produce "The Typical Pattern of a North Carolina Snowstorm"
  • The composite maps  were generated from the NCEP Analysis Disk (Mass et al. 1997) (@ 60ºN, 361 km grid space)
  • A discernible ridge is found in the West; 86.7% of the 9-panel plots contained this feature
  • A predecessor Low is found in the NE; 73.3% of the 9-panel plots contained this feature
  • Maps of the anomalies were also generated and analyzed.
  • The composite maps were compared with the plots for the January 25th, 2000, snow event

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