Simple chart showing the federal funds rates since 1955. As you can see the rate is currently in a falling wedge pattern which should eventually break to the upside. However given the conditions of the global economy, for now, we may very well be at the peak at the top of the channel with a downward move pending.
If this happens to be the peak and feds continue to cut rates from here, we could see interest rates at -1.8% or lower by the end 2020 / beginning of 2021. The time is derived by the last two drops from the top to the bottom of the channel which took ~460 days.