How to extrapolate?

Hi, new to influxdb and Chronograph.
I have nice time series at 5 or 10 minutes intervals in influxdb and graphs updating in realtime on Chronograf. I haven’t explored Grafana yet.

Question: How can I add an extrapolation to a time serie to show the future trend for the next 3 hours, for example ?

See this example that I made in LibreOffice-Calc.