The fourth of five types of aviation weather information discussed in this handbook is forecasts.

This chapter will discuss many forecast products produced primarily by the NWS that are either specific to aviation or are public products of interest to aviation users.

As with other products discussed in this handbook, the visualization of these products has evolved over the past decade with the use of internet websites. The use of static black and white depictions of aviation forecasts is almost a thing of the past. Today’s websites provide the forecast products in color and offer options to select and overlay multiple products.

Today’s aviation weather websites, including those of the NWS, continue to improve the content and visualization of forecast products. Unfortunately, it is not practical to update this handbook with every change to a weather product.

Examples of weather products in this handbook represent one way of how they can be visualized on a user’s viewing device (e.g., computer, tablet, mobile phone, or cockpit display). The examples shown in this handbook are from the NWS’ websites.

For this handbook, forecasts include the following:

There are many wind and temperature aloft forecasts and products produced by the NWS. Each NWP model (i.e., sometimes referred to as computer models) outputs wind and temperature at multiple levels. The primary output of these forecasts is a gridded binary code format intended for use in flight planning software.

There is no official wind and temperature aloft model for flight planning. Depending on the computer model, the validity times, time intervals, and altitude levels will vary. Some models produce wind and temperature forecasts at hourly time-steps while others produce forecasts at six-hour time steps. A few models provide wind forecasts at 1,000-ft altitude levels while others are mostly at 3,000-ft altitude levels. The data points (location) will also vary depending on the source.

Because each computer model is based on different algorithms and physics, the wind and temperature forecasts will vary from model to model. These differences are due, in part, to the model’s forecast pressure patterns on the surface and aloft. In addition, some models have more detailed terrain as well as finer spacing between data points.

For many years there was just one set of wind and temperature forecasts, known as the FD Winds (then later as the FB Winds), which were presented in a coded text table format (see Section 27.2.1.1.2).

Today’s flight planning software directly imports wind and temperature data from various computer models, which has effectively made the coded text table format obsolete.

Although FB winds are still produced today, they are archaic compared with model output available to the pilot and flight planner. FB winds:

In contrast, for example, the NWS’ Rapid Refresh model winds:

This section describes the details of the FB Wind and Temperature Aloft Forecast product. Other sections within this handbook provide additional wind and temperature aloft forecasts (i.e., constant pressure level forecasts [see Section 27.11.1) and the global wind and temperature forecasts provided under the WAFS (see Section 27.8)].