National Weather Service United States Department of Commerce


Assessment of Ceiling and Visibility Climatology During Observed Snowfall

Kenneth R. Cook and Bria Gruenbacher
National Weather Service, Wichita Kansas

November 01, 2006

Below is a climatology of Visibility and Ceiling Height when Snow is observed for each of our TAF sites. This was compiled using hourly observation data from NCDC dating from June 1st, 1976 through June 1st, 2006. Here is some information regarding the graphical content:

  • Box and whiskers plots represent the observed ceiling height for each category. Whiskers represent the extremes, the boxes represent the majority of cases. The yellow is the 75th Quartile, the green is the Mean, the red is the 25th Quartile. I suggest using the mean value or certainly something within the box for a ceiling to match a specific visibility category (unless ongoing snow suggests otherwise) based on the intensity of the snow you expect.
  • Cases - This is the percent and number of occurrences of this visibility category versus the total number of snow observations. In other words, this is the climatological probability of occurrence.
Blizzard Observations from 6/1/1976 to 6/1/2006
1 - 1/18/1996
1 - 1/01/1991
1 - 2/10/1981