DescriptionMETAR data includes ASOS, AWOS, and non-automated reports that follow the Federal Meteorological Handbook No. 1 (FMH-1) Surface Weather Observations and Reports for Aviation Routine Weather Reports (METAR) and Aviation Selected Special Weather Reports (SPECI) for single station and collective messages. MADIS started collecting these reports over the US July 1, 2001 and moved to global coverage on March 13, 2006.
METAR reports that were received before 01 January 2015 were decoded by the Earth System Research Laboratory (ESRL) Global Systems Division (GSD) Information and Technology Services (ITS) branch. ITS ingests METAR reports from NOAA port via the Satellite Broadcast Network (SBN) and also pulls global METAR data from the Telecommunications Gateway via FTP every 5 minutes. METAR reports received after 31 December 2014 are decoded using NWS NCO decoders and originate from the same sources mentioned above.
Data ScheduleMost stations report once per hour at a scheduled time, some have a schedule that calls for three reports per hour, several more reports can be generated when triggered by certain meteorological conditions.
Data arrive on a continuous, asynchronous schedule, and the current and previous hour's data are processed every 5 minutes. National data source standards call for MADIS to store these data starting 15 minutes before the hour and ending 44 minutes after the hour (e.g., the 0000 file covers 2345 - 0044).
Data that arrive after 2 hours following the time of the observation are processed in a "data recovery" mode, where once a day batch processing is performed to reprocess data that are 35 days, 7 days, and 1 day old. These data are available with all communications methods supported by MADIS except for ldm.
VolumeTypical daily volume for all MADIS datasets can be seen here.
RestrictionsNo restrictions. All observations are publicly accessible.
- Federal Meteorological
Handbook No. 1 -- Surface Weather Observations and Reports
This is the definitive United States standard for the Aviation Routine Weather Report/Aviation Selected Special Weather Report (METAR/SPECI) code formats.
- NWS ASOS News and Resources
The NWS ASOS home page.
Last updated 7 November 2014