A CME does not kill HF immediately. The operator advantage is the lead time between launch and arrival, which gives you time to expect rising Kp and shifting band behavior.
Fast Earth-directed events usually matter most for polar paths first. When the shock lands, lower bands often stay useful longer than the high-latitude high bands.
Use this tracker with the aurora dashboard and globe. CME arrival windows, southward Bz, and rising solar wind are the trio that turns a quiet day into a propagation problem.
Earth-directed CME watch