There are two methods of measuring the amendment response time (ART) of TAFs. One method looks "backwards" from an amendment and identifies the "triggering" observation. This method records "proactive" or "forecaster initiative" TAFs and The second method looks "forward" in time for a response when an observation is not satisfied by the most recent TAF. This method records the number of observations requiring amendments for which "no response" was issued and credits a new observation as a valid response, i.e. the weather changes to match the forecast.
TAF amendment response time calculations are a blend of both the "forward" and "backward" methodologies. Monthly and quarterly results are published by individual aerodrome and grouped by issuing office.
In addition to providing summary results, an analysis of the event log itemizes the response by amending criteria. The paper concludes with suggestions for improving TAF amendment response time.
The 8th Conference on Aviation, Range, and Aerospace Meteorology