'Warm and cool air masses meeting near the North Pole' would likely to form a 'subtropical jet stream'.
<u>EXPLANATION:</u>
Subtropical-jet stream is known as the space where there is a higher amount of force which is located at the upper level above the 'subtropical jet stream'.
The exact location of the 'subtropical-jet stream' is located at the North phase of 30 Degrees and the reason behind this is due to the variation of air which lies on the region of mid-altitude and warmer equatorial air.
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