Propagation & Weather
NOAA Space Weather Prediction Page
The go-to guys for what’s in space http://www.swpc.noaa.gov/communities/radio-communications
N0NBH HF Propagation and Solar Data Tools
A fantastic collection of useful, real-time solar & propagation tools you can use, and gadgets to add to your ham website.
Worldwide Lightning Location Network
University of Washington @ Seattle operates this worldwide network of 40 VLF sensors, with excellent displays on their website -- updated every 10 minutes.