The Point Forecast Sheds New Light on TAFs

A terminal aerodrome forecast, simply known as a TAF, is perhaps the most difficult forecast any meteorologist will ever make. A TAF is essentially an hour-by-hour forecast for conditions significant to aviation at an airport over the next 24 or 30 hours.

Scott Dennstaedt, Ph.D

Tuesday, November 14, 2023 at 09:04 AM ET

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The TAF is one of the most difficult forecasts to make in aviation weather. [Adobe Stock]

Key Takeaways:

Terminal Aerodrome Forecasts (TAFs) are inherently difficult "point forecasts" for a very small, 5-statute-mile area around an airport, leading to common misunderstandings of their limitations by pilots.
Forecasters struggle to quantify uncertainty in TAFs due to format restrictions and operational pressure, often using placeholder precipitation types (e.g., SHRA, VCSH) for uncertain convection.
Area Forecast Discussions (AFDs) are crucial for pilots as they provide plain-English explanations of forecaster reasoning and uncertainty, particularly concerning TAFs, offering a more complete weather picture.
Pilots should never use TAFs as general area or zone forecasts, understanding they apply specifically to the terminal area, and remember that surface precipitation forecasts may not reflect conditions at slightly higher altitudes.

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As a flight instructor and former National Weather Service (NWS) research meteorologist, I’ve accepted that pilots like to rag on meteorologists for issuing bad forecasts. Even so, once I got the full backstory behind the pilot’s dissent for a majority of these cases, there was nothing inherently wrong with the forecast; it was how the pilot was trying to use the forecast that was often problematic. This is not to imply that meteorologists are always accurate in every forecast they issue, but pilots tend not to appreciate the hard limitations these forecasts demand.

A terminal aerodrome forecast, simply known as a TAF, is perhaps the most difficult forecast any meteorologist will ever make. Think about the challenge these forecasters face. A TAF is essentially an hour-by-hour forecast for conditions significant to aviation at an airport over the next 24 or 30 hours. This includes a forecast for details such as wind speed and direction, cloud coverage, ceiling height, prevailing visibility, and precipitation type.