USD Liquidity vs S&P vs BTC - Liquidity Leads Assets

Plotting USD Liquidity for the past 5 years versus the S&P and Bitcoin. Made twitter-famous by Raoul Pal and Arthur Hayes. As we can see in the chart, liquidity is tightly correlated with the S&P and also drives Bitcoin cycles.

Liquidity looks to lead price movements in both assets classes.

Question for the community: How can we best forecast moves in USD liquidity?