Chapter 24, Observations 24-52
Figure 24-26. Weather Balloon and Radiosonde
24.8.1.1 Issuance
Weather balloons with radiosondes are launched twice a day worldwide from designated locations at around
1100 UTC and 2300 UTC (see Figure 24-27). It takes approximately 90 minutes for the balloon to reach
an altitude of 100,000 ft. The weather data collected is assigned the observation times of 1200 UTC and
0000 UTC. Special radiosondes may be launched at select times for various reasons, including when severe
weather is expected in a region.
Chapter 24, Observations 24-53
Figure 24-27. U.S. Radiosonde Network
24.9 Aviation Weather Cameras
24.9.1 FAA Aviation Weather Camera Network
In July 2007 the FAA, under the leadership of Walter Combs, began a program to assist Alaska pilots with
their significant needs for weather information. Combs’ passion for safe flight in Alaska provided the fuel
for much improved situational awareness, seeing the weath er picture in mountain passes. His work, along
with management support, created the Aviation Weather Camera Network.
The FAA’s Aviation Weather Camera Network (see Figure 24-28 and Figure 24-29), consists of nearly 500
camera facilities in remote or mountainous locations. Additional sites will be added to the network as they
are installed and become operational . Each site has up to four cameras. The direction of each camera (see
Figure 24-30) is provided with reference to a Sectional Chart. A “clear day” image (see Figure 24-31) is
provided for reference and comparison to the latest image (see Figure 24-32).
In Alaska, locations with cameras are marked on Sectional Charts and listed in Chart Supplement Alaska,
Section 2, Airport/Facility Directory, as well as under Section 4, Associated Data, FAA Aviation Camera
Locations.
Chapter 24, Observations 24-54
Figure 24-28. Map of FAA’s Aviation Weather Camera Network in Alaska, the CONUS, and Canada12
Figure 24-29. Map of the FAA’s Aviation Weather Camera Network in Hawaii
12 Canadian camera sites are owned and operated by NAV CANADA, Canada’s civilian air navigation service
provider.
Chapter 24, Observations 24-55
Figure 24-30. Sectional Chart Depicting Hyder (4Z7), Alaska Camera Orientations
Figure 24-31. “Clear Day” Image from the Aviation Weather Camera at Hyder (4Z7), Alaska
Chapter 24, Observations 24-56
Figure 24-32. Aviation Weather Camera Image at Hyder (4Z7), Alaska
24.9.2 Visibility Estimation through Image Analytics (VEIA)
VEIA, which is available on the FAA ’s Aviation Weather Camera Network, is an algorithm that uses the
FAA’s Aviation Weather Camera Network to produce visibility estimates (in s tatute miles) by analyzing
the views in the camera imagery. VEIA uses all of the cameras at a single site to produce one prevailing
visibility estimate for that location by identifying and measuring the strength of the edges of permanent
features in the landscape/scen e and comparing them to a clear day reference. VEIA visibility estimates
allow users to quickly access visibility estimates at the departure location, along the route, and a t the
destination between sunrise and sunset (not during twilight hours or at night).
VEIA visibility estimates are supplemental information, for use with other meteorological information,
displayed in conjunction with the specific site’s camera images. The visibility estimates are accessible on
the FAA’s Aviation Weather Camera website. See Figure 24-33 for an example VEIA visibility estimate.
Chapter 24, Observations 24-57
Figure 24-33. VEIA Example at Bald Mountain (K7BM) in Colorado
24.9.3 Visual Weather Observation System (VWOS)
VWOS, which is available on the FAA’s Aviation Weather Camera Network, is an advanced camera system
that is comprised of a suite of weather sensors and 360-degree camera images that collectively observe and
report several critical data fields , including winds, cloud height, visibility, present weather, temperature,
dewpoint, and pressure. VWOS uses automated processes to self-check and validate its operations and data
outputs. It provides operators with visual and textual weather observations a s guidance, for use with other
weather information, to make flight decisions into airports that do not possess an AWOS/METAR.
In the future, VEIA will be a core component of VWOS.
24.9.4 Issuance
Camera images are available on the FAA ’s Aviation Weather Camera website , which can be found in
Appendix G. Images are generally updated every 10 minutes. The time of the last update is indicated on
each image. Actual site conditions may differ from displayed images due to a variety of reasons
(e.g., rapidly changing weather conditions, image update frequency, or optical distortion).
Camera images are to be used to improve situational awareness. They are not to be used to determine
weather minimums for VFR or IFR flight, unless authorized by the Administrator of the FAA.
In addition to the camera images, the website also delivers a variety of safety of flight information, including
adverse conditions (e.g., AIRMETs and SIGMETs), current conditions [e.g., METAR s, radar, satellite
imagery, and weather trends (see Figure 24-34)], TAFs, PIREPs, and other aeronautical information
(e.g., RCOs, TFRs, and charts).
Chapter 24, Observations 24-58
Figure 24-34. Weather Trends Example at Unalakleet (PAUN), Alaska