Early Warnings: using Trend Shift Indicator divergence.The attached chart has much of the explanation.
Here are the highlights:
TSI gives early sell warning via high values (near 170), relative highs, or in rare cases an "x" signal.
Divergence with price is also a key indicator of future action.
Examine the divergence illustrated during the price drop and the (still red) TSI values.
I hope this is helpful. Feedback appreciated.