FORT KNOX, Ky. — An Army chief warrant officer stopped by the Air Force weather desk at Hangar 1 on Godman Army Airfield.
“What do you have for me?”
Barney Burr guided the pilot through several weather forecast slides prior to his departure from Fort Knox a few hours later. For Burr, supervisor of Operating Location B, 3rd Combat Weather Squadron, these briefings are a standard part of his six-person team’s mission: to ensure pilots flying to and from Fort Knox get where they’re going safely.
“Anytime a pilot flies, we give them a weather brief,” said Burr. “If the pilot is staying local and the weather is good within 35 nautical miles of here, we give them a verbal brief. If they’re going outside of that, or the weather is bad, we have to generate a form.”
Burr said sometimes people ask his forecasters to predict road conditions: not their lane, although they do predict the weather that will affect road conditions. What they do focus on is what's happening above the ground. They chart specific criteria within five nautical miles of their instrumentation site located at the center of the airfield.
The criteria include visibility, sky conditions such as the ceiling, wind speed and direction, thunderstorms and freezing precipitation, and other weather phenomena.
“For the ceilings, you’re looking at 1,500 feet,” said Burr. “Anything 1,500 feet and above, we’re good because these guys can take off, land and fly in that without any problems.”
The issues come when the ceiling drops below 1,000 feet.
“We have criteria for that, and the forecast has to say it,” said Burr.
The ceiling lines of distinction reflected on a forecast are drawn at below 1,500 feet, below 900 feet, and below 500.
“Usually when they get below 1,000, it makes it lot more difficult — not for them to take off— but to land,” said Burr. “Anything below that, they have to use instrument flight rules.”
For visibility, three miles from the airfield and greater is good. For winds, the threshold is 25 nautical miles per hour. Depending on the direction, anything less than 6 knots is considered good. And as for freezing precipitation and thunderstorms, good is no freezing precipitation within the the area, and 15 nautical miles or more for thunderstorms.
Some fluctuation is built into each forecast since weather changes over time, and forecasts will reflect what is the predominant weather during a given hour rather than what may change within a minute or two. Burr said with that in mind, the standard for each squadron is high.
“We’re averaging about 90% accuracy,” said Burr. “We can get a forecast wrong; from the time we put one out it’s valid for about 30 hours — really accurate the first eight to 12 hours — but usually where we start to slightly lose that accuracy is about 12 hours out.”
When weather does change, part of their job is to amend forecasts and ensure that pilots scheduled to take off or land are made aware of the changes.
“Horizontal consistency is a big deal,” said Burr.
Besides a daily brief the forecasters generate for pilots on a form called a Mission Execution Forecast, or MEF for short, they also produce a five-day forecast that those staying local can monitor.
Burr said what makes his all-civilian team of forecasters superb at their jobs is their tremendous amount of experience.
For instance, Burr served in the Air Force 21 years before retiring and has been here about two years. Most of the members of his team have either been working at Fort Knox since the early 2000s or retired from the Air Force as forecasters — or both. One of those is Tim Deely.
Deely served 24 years in the Air Force as a weatherman, beginning in 1980, before retiring. He joined the unit in 2000, having seen a lot of changes over the past 42 years.
“The basics of weather observation and forecasting have not changed, but the technology has quite a bit,” said Deely. “There are a lot more things available to use. The only challenge is the network issues with accessibility to certain websites at times.”
He said back in 1980, forecasters often had to rely mostly on themselves, using observations in forecasting, and charts that they analyzed. Whether forecasting back then or today, however, he admits there is an art to the science of weather—
“… art, as in you have to be pretty open-minded to take in various opinions,” said Deely. “Forecasting is best done when you have a group of people together.”