When using the query builder there is an option to select data sources:
If I'm using this to get historical data (at a resolution of daily), and I select historical observation data sources and "Forecast", how will this work.
Will all data in the past still be based on historical observations or will historical forecast data be used too? And if so how? Will it just be used to plug gaps in historical observations or will it be averaged along with the historical data?
Thank you for your question. For historical data, the main options are 'observations' (obs), 'remote' and forecast. For historical data, remote must also be enabled in addition to forecast to indicate that non-observation data should be used. When no option is enabled, the default is for all three to be enabled.
Remote and forecast data are used when observation data is missing and for quality checks against the station data - it is not combined with observations if the observations are complete.
The order of preference is to use station observations, then remote data (satellite or radar) and then forecast as a fall back. In most cases, 'forecast' actually refers to the hour zero initial state of the forecast model and so is actually the current picture of the atmosphere which the forecast model is then based upon. Historical forecast data is available for January 2022 onwards. In typical cases forecast is not needed to fill in the observations, and even when it is used in most cases only an hour or two of forecast is used while waiting for observation data to populate
Regards
Visual Crossing Support
