Airport Dense Fog Study

by Jan Jackson and Amanda Worrell

 

The Blacksburg Weather Forecast Office prepares specialized weather forecasts for three airports in Virginia: Roanoke, Lynchburg and Danville; and two airports in West Virginia, Bluefield and Lewisburg. One of our toughest challenges is forecasting dense fog, with visibilities of a quarter mile or less. As the graphic below shows, the southern and central Appalachian mountains and foothills have some of the highest number of days with dense fog per year in the eastern U.S. The average for our area ranges from 40 days in the piedmont, to 80 in the mountains.

Days of Dense Fog per year

 

In order to help with our forecasting, 30 years worth of data, (1973 - 2003), were studied for each airport to determine how often, and at what time, dense fog was reported. The data was available in four 6 hour periods, from 4:00 am to 10:00 am, 10:00 am to 4:00 pm, 4:00 pm to 10:00 pm, and 10:00 pm to 4:00 am. The following are the results from each of the airports.

 

Bluefield

Fog Descending over East River Mountains

 

Graph showing days of dense fog in Bluefield

Danville

Dense Fog picture

Graph showing number of days of dense fog in Danville

 

Lewisburg

Fog in Lewisburg

Graph showing number of days of dense fog in Lewisburg excluding the hours between 4 AM and 10 AM

Graph showing dense fog days between 4 AM and 10 AM

Lynchburg

Dense Fog

Graph showing dense fog days in Lynchburg

Roanoke

Dense Fog picture

Graphic depicting the number of days of dense fog at Roanoke