A north wind moves from the north towards the south. If you read the name as its destination, the mental picture reverses before you have even considered speed.
Start with the convention
The National Weather Service glossary defines wind direction by where the wind is coming from. That convention gives words such as northerly a specific meaning in a forecast.
For a paper exercise, draw north at the top of a page. Place a starting point there and draw the movement towards the bottom. Label both the source direction and the direction of movement.
Read the symbol’s own key
Do not assume every arrow in every application uses an identical visual convention. A wind barb, a movement arrow and a boat heading symbol need their own explanations.
If a graphic is unclear, consult its legend or documentation rather than deciding from the arrow’s appearance alone.
Keep direction within the larger forecast
A direction does not tell you wind speed, gusts, changes over time or local conditions. This vocabulary exercise is not enough to decide whether conditions suit a boat or crew.
Pair it with forecast issue and valid times. A useful reading identifies what the direction means, where the forecast applies and when it describes conditions.