Irrlicht Engine

You could make local only simulation and then stream through planet wide data for the weather system if you are using a heightmap based approach. Infact using a heightmap based approach you could easily account for pressures and air temperatures using pixel shader computations.

A recursively changing noise seed based heightmap would be easy. Much better would be, getting yourself a NASA Pressure and temperature map(they also have air moisture, solar input etc, maps) converting it into several heightmaps and do computations on those as a start. That way you can also better see what you should be getting.
In total however for a real simulation you would have to account for Coriolis force(earth gyro spin), Day and night cycles, Temperature, Pressure, Ocean and land heat transfer, air moisture and solar insolation. In other words, quite a bit.

i adrealy have to account for these data for generating the environement anyway ;p the question is always wich depth is needed to fool the user not what is needed to make the most realistic simulation possible but if generating such data allow to have a more realistic weather simulation for special event then
if (rand() >= 1 )
{
TropicalStormWind
}

i would say it's worth investing a bit

I forgot to mention some factors: Material Thermal properties, Areas in Shadows, Geological influences, Human caused emissions... All of the mentioned terms being highly simplified.
But nevermind those, we don't need em yet...

Just an idea, you could actaully use normal maps (sorta) to map wind directions(or just normal map for wind direction) for your atmosphere, and heightmaps for pressure, temperature, moisture.(Or simpler if you prefer) Then use the Wind normal map to alter the pressure, temperature and moisture distribution, you can also account for heat absorption of land/ocean (just another black and white heightmap). How you apply it to a 3d environment though is a bit tricky, you would have to look for ideal factors/conditions in the computed data and create resultant elements per pixel, probably quite computationally expensive. Infact I myself might try my hand on this a bit, it also might be a good opportunity to brush up on my rusty Shader skills.