Joint Probability of Selected Cloud and Visibility Thresholds Around Koblenz, Germany.

The areal probabilities of adverse weather at a station network consisting of Cologne, Frankfurt, Hahn, and Bitburg have been determined for the period of record 1961 through 1970 except September 1967 through August 1968. Individual and joint probabilities of adverse weather for eight categories of ceiling and visibility observations defined in a previous report see reference 1 have been tabulated. The 9-year period was chosen due to a large amount of missing data at Cologne during the months indicated above. The identical set of tabulations for the complete 10-year period without Cologne did not reveal any notable differences in the probabilities. The extensive set of tables reflects a selected number of adverse weather conditions. The reduction in joint probability estimates with increased areal coverage is evident for all adverse weather categories. Tabulations of probability estimates at each individual station and joint probability estimates of adverse weather are listed in annual, seasonal, and monthly summaries selected months only. Author