The first demand of @majedforcast is «  data for overhead pressures and contour lines, especially at level 500 ».
This is a good example to show that these isolines are already available (Geopotential heights at 500hPa), but they are so hidden and difficult to find...
Just to illustrate this old post:

https://community.windy.com/topic/10464/improve-the-isolines-accessibility?_=1611579480015