MesoWest Quality Control

MesoWest has been designed for use by National Weather Service meteorologists and other professionals for protection of life and property. Comments and suggestions for improvement are encouraged and can be sent to meteo-mesowest@lists.utah.edu.

The Quality Control of weather information begins with checks that are applied to the data as it is processed. These include "range checks" for all variables as well as a statistical check for several [temperature, relative humidity, and pressure].

The SNOTEL network flags each variable at each station either 'valid' or 'suspect'. These flags are also used in MesoWest quality control.

The key to the coding of information is based on the quality control checks:

• Black/OK: data has passed all QC checks. (Note that Maximum/Minimum Summaries and Station Data Displays use Green for this category.)
• Orange/Caution : some data has been flagged by the statistical check and should be used with caution.
• Red/Suspect: some data has been found to be outside reasonable bounds.

Whenever viewing data in the absence of QC flags, colors, acronyms, and/or statements, all such data should be treated with caution. Viewing the QC column on an individual station plot is a good way to verify data quality when using one of the weather observation products containing tables without QC such as the most recent maximum and minimum in the 5 day Maximum/Minimum Summaries. When you see a QC flag or color specified for a weather station it will not be variable-specific. Thus, you will need to look at all the individual variables to determine which one should be used with caution. In most cases only one variable is responsible for the yellow or red flag color.

Occasionally, the station's name and/or elevation will be colored yellow or red. This is to indicate that the station's location or elevation is uncertain (yellow) or incorrect (red). Special care should be taken when considering data from these stations, since the data may pass the qc check explained above, yet originate from a station in another state!

• 5 Day Maximum/Minimum Summaries: In addition to the QC available in other programs, there is also a check for the amount of data that was available for each daily period for the temperature, relative humidity, and wind speed summaries. Adequate, marginal, or inadequate amount of data available to define the maxima and minima are displayed in green, yellow, or red respectively.

• Precipitation Monitor and Precipitation Summary: There is no QC applied to these data products so please use with caution. QC for precipitation may be verified with QC for an individual station plot.