One data point...how many GRIB blocks make up the upper wind forecast? What BOM is doing is "Homogenise" key data sites with long recording history. They then use these sites to adjust across the country to show a warming trend across the entire database. Effectively, BOM will reduce the key temp data to a handful of data points to represent the entire continent. Why one site? Why ANY site? Any thinking person must ask, critically, is the temperature record now trustworthy?