Here is a simple example of how NOAA manufactures station data. The station at MORRISVILLE 6 SW in New York stopped reporting data in February 2013. The raw data file is shown below (click for a larger image.) Missing monthly data is marked by -9999.
The manufactured data (shown below) continues through the present and is marked with an “E”
We know that temperatures can vary several degrees within 50 yards, but they are pulling data in from stations tens of miles away, and reporting it to a precision of 0.01 degrees.
NCDC then releases temperature graphs to the public showing warming, with no mention that about 40% of the current station data is manufactured, without any underlying measured station data.