When watching WMC Action News 5 or looking at the First Alert Weather app on your phone, you are usually seeing temperatures, maybe dew points, also cloud cover or even visibility, but have you ever wondered how we are getting these readings?
A lot of our current weather information is supplied by a weather station called ASOS or Automated Surface Observing System. The ASOS program is a joint effort between the National Weather Service (NWS), the Federal Aviation Administration (FAA), and the Department of Defense (DOD).
ASOS is the nations primary surface weather observation network, and the reason why we use the stations is because they help support weather forecast activities and aviation operations. But they also help support the needs of the meteorological, hydrological, and climatological research communities.
According to the NWS, the ASOS sites provide more information about the atmosphere and more frequently from various locations. This is key in improving forecasts and warnings, which in turn, helps increase the accuracy and timeliness of its forecast and warnings.
In addition to improving forecasts, ASOS stations provide critical information for the aviation community. Weather conditions often threaten air safety, and the sites help measure weather parameters at critical areas, such as airport runway and touchdown zones.
Over 900 ASOS stations report basic weather elements across the U.S. which include:
- Sky conditions: cloud height and amount (clear, scattered, broken, overcast) up to 12,000 feet
- Visibility (to at least 10 statue miles)
- Basic present weather information: type and intensity for rain, snow, and freezing rain.
- Obstructions to vision: fog or haze.
- Pressure: sea-level pressure, altimeter setting.
- Ambient temperature, dew point temperature.
- Wind: direction, speed and character (gusts, squalls).
- Precipitation accumulation.
- Selected significant remarks, including – variable cloud height, variable visibility, precipitation beginning/ ending times, rapid pressure changes, pressure change tendency, wind shifts, peak winds.
As you can see, ASOS sites across the country are important in helping meteorologist show the why as to what is happening in our weather outlook. They also help us tell the weather story each an every day.