Tempest weather page hourly chart

Hello new Tempest owner here . Been up and running a few weeks now.
Question is on the hourly chart what does the line below the precipitation outlook
stand for ? There is an arrow to the left of a number . The arrow fluctuates in direction either up or down. Is it wind ? Thanks !

The number is the forecast non-gust wind speed. The arrow is the direction that the wind is blowing TO, not where is is coming from…