A historic day of space weather is unfolding today! We have just had the early arrival of a very strong CME with the Bt spiking to > 90 nT. 1s mag data reported 94 nT which is the strongest reading since solar cycle 23. More notably, we are undergoing the first S4 / severe radiation storm of this cycle and proton fluxes are now exceeding 30,000 PFU. This makes it one of the strongest radiation storms ever recorded, surpassing the event in October 2003. We may see G4+ storming today and widespread auroras across North America down to mid- and even low-latitudes. Stay tuned and make sure your camera batteries are charged for tonight!