If currency markets continue to experience high volatility with a strengthening US dollar, I think equity markets, including North American markets, will follow suit.
So, I’ll keep a close eye on those as potential canaries in the coal mine; e.g., to see whether the spread continues to widen (downward) between the SPX and the Pound:USD Forex pair, as shown on the Year-to-Date comparison chart below (the Pound lost 8.75% last Thursday and Friday).