Final answer:
The observed wind direction at Dallas can be parallel, perpendicular, opposite, or variable to the pressure gradient force.
Step-by-step explanation:
The observed wind direction at Dallas can be parallel, perpendicular, opposite, or variable to the pressure gradient force.
In the context of this question, the wind direction can be parallel to the pressure gradient force if the wind is flowing directly from high pressure to low pressure.
Alternatively, the wind direction can be perpendicular to the pressure gradient force if the wind is flowing across the isobars, which are lines connecting areas of equal pressure.
If the wind direction is opposite to the pressure gradient force, it means the wind is flowing from low pressure to high pressure.
Finally, if the wind direction is variable, it means the wind does not have a consistent direction in relation to the pressure gradient force.