Probability of a White Christmas
Conterminous United States

Statistic: 30-year probability of a white Christmas 
Time period: 1961-1990
Time interval: annual
Spatial format: grid
Data format: ARC/Info ASCII GRID

 Projection: Geographic
Spatial resolution: 1.25 arc-minutes (~2 km)
Spatial Extent: Conterminous United States
Units: percent
Date created: August 2000
Methods: Statistical derivation from mean snow depth on the ground during December, derived from mean snowfall and mean temperature (temperature mapped with the PRISM modeling system), and Gaussian filter resolution enhancement. See FGDC-compliant metadata for details. 

Examples 
 
Probability of a white Christmas
Features
  • Reviewed and approved by the US National Climatic Data Center 
  • Incorporates topographic effects on probability of white Christmas 
  • Includes coastal and lake effects on probability of white Christmas 
  • Accounts for temperature inversions on coasts and in inland valleys 
  • Uses upper-air temperature data to capture high-elevation patterns 
  • Consistent treatment and spatial quality control of station data 
  • Consistent coverage across all state boundaries 
  • "Universal" geographic (latitude/longitude) projection allows conversion to any other coordinate system 
  • Data format allows for easy import into ESRI's GIS products, as well as MAPINFO and Intergraph's GeoMedia 
Data used in analysis
  • 4,431 National Weather Service stations for probability of a white Christmas 
  • 4,524 stations for snow depth on the ground
  • 7,349 stations for mean snowfall
  • 6,400 stations for mean temperature
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