Boy, that would be nice to have WD look at a file that gets refreshed every period of time and accept that as data!
The closest thing I've run into is the Peet Brothers 2100 which has three types of output and just one works with WD.
I can't recall how long ago it was that I set one up but it works for reading the stream, not file, from the serial port from the Peet. Not exactly what you want, but maybe there is some relatively 'light' programming that would look at the tile you were sent, parse it into an acceptable stream.
Drivers are a MAJOR pain to write (for me, at least) but for some it seems to be easier to do. I know that WeeWx has a bunch for stations and when I looked at the code it runs from 'relatively' simple to what the heck are they doing, especially when they use OOP techniques and stuff without a lot of comments in the code to tell you what and why they are doing it.
If you find a WD driver that does what you want, or close, please let us know. Dale