Air Traffic Management Concept Baseline Definition - The Boeing ...

Dissemination
Forecasting
Analysis
Observations
Figure 5.14 Functional Areas Of Aviation Weather
The NWS operates much of the meteorological observing network, and it prepares
weather analyses and forecasts at the National Center for Environmental Prediction
(NCEP) and the Aviation Weather Center (AWC). The NWS distributes weather
information to users electronically via land-based networks and satellite communications
systems and by voice. The FAA also collects weather information, including surface
observations in the terminal area and radar observations of storm locations and intensity.
NWS meteorologists working in the Center Weather Service Units (CWSU) at each
ARTCC, in the Central Flow Weather Service Unit, and at Flight Service Stations (FSS)
provide analysis and forecasting services for their FAA colleagues, and produce weather
information that is then relayed to controllers and pilots. A few of the major airlines have
their own meteorological centers, but most receive their weather information from the
NWS and/or private sector providers of weather information.
Observations of current meteorological conditions are collected at airports and at other
sites located throughout the country and offshore. These include surface and upper-air
observations of winds, temperature, pressure, moisture, precipitation, cloud type and
amount, radar reflectivity, and soil and water temperature, among others. These data are
used to prepare objective analyses of current weather conditions that affect aviation
operations, referred to as Aviation Impact Variables (AIV’s). Examples of AIV’s include
ceiling and visibility, precipitation, icing conditions, winds aloft, runway winds, and
turbulence.
Objective analyses also provide initial and boundary conditions for numerical weather
prediction (NWP) models and other forecasting tools. Weather conditions are forecasted
on time frames as short as 30-60 minutes (referred to as ‘nowcasts’) to as long as several
days. Nowcasts provide useful information for managing air traffic flows into and out of
terminal areas, and for providing information to support tactical decision making, e.g.,
vectoring aircraft around hazardous weather. For aviation applications, the longer-range
forecast periods of greatest interest are probably in the 3-24 hour time frame. These
forecasts support strategic planning and decision making by providing information that
helps planners and air traffic managers coordinate aircraft and airport operations. Once
the weather analyses and forecasts are prepared, the information must be distributed to
users in a timely manner. Weather information is highly perishable, so that the technology
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