Verification of a Real-Time System to Estimate Weather Conditions at High Resolution in the United States

The Weather Channel in Atlanta, Georgia (TWC) and Weather Services International Corporation in Andover, Massachusetts (WSI) jointly developed a system called HiRaD (High Resolution Aggregate Data) that produces synthetic current conditions or surface weather conditions for any arbitrary point within the conterminous United States (CONUS). Concurrently, a shadow HiRaD system produces synthetic surface weather conditions that differ from the primary system only as a result of the systematic withholding of input surface observations or METARs from the core system. The output of this system is called the data denial result and is used directly or comparatively to measure the skill, variability and bias of the HiRaD estimation techniques.

The data denial verification is performed to quality control and to improve HiRAD output data. Hourly comparisons between estimated observations and METAR observations have been performed for two sample sizes – one for the entire list of conterminous United States METAR points, another for METAR locations representative of the top 100 Designated Market Area (DMAs). Initial results from the nationwide sample show an average error of less than 2 degrees Fahrenheit for temperature, approximately 2.2 degrees Fahrenheit for dewpoint temperature and 3 miles per hour for wind speed. Diurnal, seasonal and geographical variations in the mean absolute error field were noted for each variable. An archive of the verification results has been created to track the performance of the system as it continues to be developed and improved. The results of the verification over a period of several months will be presented and discussed.

An unintended finding resulting from data denial Verification has been to identify locations where instrument or encoding issues have arisen with METAR observations. Ideally, data denial verification will used as a tool to evaluate that quality of new data sources yet to implemented in HiRAD.