KBA-01418: NOAA Weather Observations and Site History


How do the weather readings get recorded in the Site Conditions History?


Here is an overview of the process:

  • Your site needs to know the weather observation for a ZIP code.
    • Several times a day, the ATC service will request the current observation for all the locations where you currently have an ongoing project.
      • ATC records these conditions by ZIP code in the Site Condition History.  Since readings are stamped with their observation time, ATC can identify duplicates and only stores unique readings.
    • Every time a Project Dashboard is viewed, a current observation is requested if the observation on hand for that location is more than 20 minutes old.
  • Requests for current conditions are received by the Spitfire Weather Service by ZIP code.
    • SWS looks up the GEO Coordinate (lat/lon) for the zip code using the Google GEO service
    • SWS requests a list of NOAA weather stations serving that GEO location.
    • SWS checks its cache to see if it has a current observation for the weather station.
      • NOAA guidelines call an observation current if it is
        • Within 20 minutes of when it was last acquired
        • Within 60 minutes of when the observation was recorded by NOAA
      • Examples:
        • an observation acquired from NOAA’s web service at 11:59 that contains a reading recorded by NOAA at 10:40 is “current” until 11:39
        • an observation acquired from NOAA’s web service at 11:59 that contains a reading recorded by NOAA at 10:05 is “current” until 11:19
      • If SWS does not have a current observation on hand, it requests one from NOAA.
        • Important Note: the observation obtained from NOAA can be hours or even (in rare instances) days old.

Additional Comments:

Note: weather observations are not forecasts!  An observation is a set of facts recorded by NOAA and published by the National Weather Service via a REST feed on its internet web service. NOAA does not publish conditions by ZIP code, but uses its network of weather stations, predominantly at airports.  Not every NOAA station offers data via the API; not every station returns complete data!

KBA-01418; Last updated: November 20, 2018 at 13:59 pm;
Keywords:  weather conditions;weather stations;