Remember those vague Area Forecasts (FAs) that you try to interpret and figure out what portions of what areas the un-decoded text is talking about as you think about alternate minimums, cloud ceilings over an area bigger than a TAF site covers, or as you try to plan a cross-country flight through a region? Well, many people only use them periodically, but they can actually be very useful.
Specifically, while the actual forecast is very useful, a little paid attention to part of the forecast is the “Aviation Forecast Discussion. (AFD – no, not the green books with airport information, the weather product).
The Area Forecasts (FAs) cover big areas that are broken down into regions including San Francisco, Salt Lake City, Chicago, Boston, Dallas/Fort Worth, Miami, and the Gulf of Mexico. But the Aviation Forecast Discussions further break down these regions into areas such as Milwaukee, Amarillo, or Sacramento for much more detailed, and focused, information about a section of the greater region.
This is personally where I start many of my morning briefings for flying in a local area. Each of these sections of the map include forecasts written in plain language (mostly) by a local National Weather Service employee who is on site in that region. It will include discussion of cloud heights and ceilings within that specific section of the area forecast and includes good local knowledge and interpretation.
These AFDs will talk about expectations that the local weather forecaster has of what the weather will do within the time period of the forecast (typically a 24-hour period) and many times offer interpretations based on local knowledge and experience. I have many times seen notes that say something like, “the models say such and such will happen, but since I have lived here for 40 years and watched our weather I know the model will be wrong and it will probably actually do something completely different.” Really, they do write stuff like that.
The AFDs are effectively the discussion of how an FA was developed and what information was available to the forecasters to create the overall FA, just on a section by section process that offers much more granular weather information that can take into account local weather phenomena.
These local AFDs can be great insight into what weather is really going to be doing in a local area and are a good resource to add to your bag of weather resources. Before you make your next flight, get into the weeds a little further and see what details the local weather forecasters might be able to provide you that you might have previously overlooked or not even knew were available as a resource
For more information about Aviation Forecast Discussion data, visit this link (http://aviationweather.gov/fcstdisc) on the Aviation Weather Center web site.