Note wind directions are parallel to contours. Friction Wind blowing near Earth's surface is slowed by frictional drag from surface features. Increasing friction reduces the Coriolis force which is proportional to wind speed. The diminished Coriolis effect can not balance the influence of the pressure gradient and results in non-geostrophic winds close to Earth's surface. Winds are oblique to isobars , the angle between wind direction and the pressure gradient is dependent upon the character of the underlying surface.
Friction decreases with increasing elevation.
Friction is less significant above flat terrain or the ocean surface but still results in winds that are oriented 10-20 o from the isobars. Influence of friction close to Earth's surface results in winds that are oriented at an angle to isobars. Circulation in low pressure systems is therefore counterclockwise, whereas flow in clockwise in anticyclones. Cyclones require divergent air flow at higher altitudes to balance the convergent flow at the surface whereas anticyclones must have convergent flow aloft to ensure their survival. Low pressure systems would be rapidly dissipated by converging air unless the in-rushing air was balanced by a rising air column.