And with subarctic temperatures that often drop below zero, staying active outdoors is out of the question.

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Temperatures at the altitudes UAVs fly drop to 50 degrees below zero.

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The drop in the MACD-His below the zero line last week (see arrow) is also a sign of weakness.

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Temperatures would drop from the forties into the single digits overnight, and high winds would drive the windchill well below zero, the service advised.

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