Met reports are based on the
True north
ATC (ATIS) reports are always based on the
magnetic north
Wind feathers/barbs
Wind direction is
The degrees in which the wind is coming from
When wind direction number decreasing, it is :
Backing
When wind direction number increasing, it is :
Veering
Wind spins … around high pressure in northern hemisphere
Anti clockwise
Wind spins … around low pressure in Southern Hemisphere
Clockwise
Primary cause of wind
Pressure differences
Isohype is
Area of same true altitude