If forecast skew-ts were accurate, they would be fantastic.
And weather forecasting would be exact too
In reality, these thermodynamic diagrams are just graphics which are generated from the same GFS computer model.
There is no magic here. The forecasters use these diagrams too, to generate their PROB30 TEMPO +TSRA etc. There is nothing a pilot can do with these things which will produce a more accurate TAF - unless the forecaster has done a cockup which is very rare.
The wx we have been having the last few days has indeed been unstable and this shows up on the skew-ts but the weather model itself is far too coarse to predict bases and (especially) tops accurately. This is why I use
IR satellite images (and other data) to get an idea of what is really out there, before the flight.