1. Assessment of Thirty Year Fog Climatology in Wichita Forecast Area By: Matthew Harding, Butler Community College, El Dorado, Kansas Kenneth Cook, Science Operations Officer, National Weather Service, Wichita, Kansas

2. Basis for Assessment Data was collected over a thirty year period beginning in 1976 and ending in 2006. Data was collected from all five of the Terminal Aerodrome Forecast (TAF) sites that are serviced by the Wichita Forecast Office. Data sampling was oriented in northwest-to- southeast fashion across the County Warning Area (CWA) to include Russell, Wichita, and Chanute.

3. Goals of Assessment 1.To give the forecaster knowledge about climatological peaks in the number of hours where fog is reported. 2.Enhance the forecasters ability to issue dense fog/freezing fog advisories. 3.Give forecasters a better understanding of ceiling/visibility relationships in fog scenarios. 4.Better explain why certain times of the year produce more fog than others.

4. Methodology Data was compiled using the following criteria: 1.Compiling the total number of hours over the 30-year period that fog was reported at the observation site. 2.Taking the number of total fog hours over the 30-year period and break it down into an hourly distribution.

5. Methodology (Cont.) 3. Take only the hours that reported visibility of less than 5 statute miles and break it down into an hourly distribution by mileage category. I.3 to 5 mi. II.2 to less than 3 mi. III.1 to less than 2 mi. IV..5 to less than 1 mi. V.Less than.5 mi. 4. Take the number in each of the categories above and divide that into the total number of fog hours for the month for each station and come up with a distribution percentage.

6. Methodology (Cont.) 5. Determine the percentage of fog observations that have a ceiling below 3000 feet by month. 6. Of these, determine the average ceiling for the given visibility category by month. 7. With the given data, find the.75 and.25 percentile to come up with the degree of variability.

7. Results and Discussion Russell, Kansas Russell Municipal Airport

19. Wichita, Kansas Wichita Mid-Continent Airport

31. Chanute, Kansas Chanute Martin Johnson Airport

43. Summation In a study conducted by the National Transportation Safety Board from 1995-2000, weather was cited as being a factor in 3 out of every 10 fatal aircraft accidents (Pearson 2002). Data from the same study also indicated that 63% of all weather-related aircraft disasters happened in low ceilings and fog (Pearson 2002; Cox, 2007).

44. Summation (Cont.) While strides are being made in TAF forecasting, fog development and subsequent cloud heights remain one of the greatest forecast challenges. We hope that with the data shown in previous slides, that you recognize the tendencies in climatology and are now better equipped to serve your aviation clientele.