solar storm  watch your GPS connection
https://plus.google.com/109694817635388202684 for a sweet little app to help out

http://www.swpc.noaa.gov/SWN/sw_dials.html
I linked the app I'm using on the prior post.

DFW area

I like this one

http://www.swpc.noaa.gov/alerts/k-index.html

as it covers more areas, such as, data from the following ground-based magnetometers: Sitka, Alaska; Meanook, Canada; Ottawa, Canada; Fredericksburg, Virginia; Hartland, UK; Wingst, Germany; Niemegk, Germany; and Canberra, Australia

I would like to know when the K index actually causes disruption to GPS signals.

I have an app on my phone and it gives the level of solar storms all the time at the top, It's called k index monitor. I don't fly if higher than 3.