Calculating what latitude aurora is visible using KP Index

[erotavlas]

Is there a formula to calculate at what latitude you are able to see the aurora, given some value like K-index?

From the NOAA website on space weather, they have some global maps with lines showing where on Earth its most likely to see the aurora, what I'm wondering is how they calculated this.

 

[Bobbywhy]

We know that during a geomagnetic storm, the auroral zone expands to lower latitudes.

Auroral Activity Extrapolated from NOAA POES:
"The plots on this page show the current extent and position of the auroral oval at each pole, extrapolated from measurements taken during the most recent polar pass of the NOAA POES satellite."
http://www.swpc.noaa.gov/pmap/

So we would have to know the details of how they "extrapolate from measurements". It appears that there is at least four satellites contributing to this data:

The Polar Operational Environmental Satellite (POES) project operates a constellation of weather satellites in polar orbits around the Earth
http://en.wikipedia.org/wiki/Polar_Operational_Environmental_Satellites

 

[erotavlas]

thanks for that, I also managed to find this site
http://www.swpc.noaa.gov/Aurora/index.html

with an interactive map you can use to determine your magnetic latitude. I just have to figure out now, how to calculate it myself or find a service I can query online that can do it for me