Tattered Fragments of the Map

It has been remarkable to look at the radar display day after day and see virtually no echoes.

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Unfortunately, we don’t understand why the AO [Arctic Oscillation] varies so much from winter to winter, nor why the AO has taken on such extreme configurations during four of the past six winters. Climate models are generally too crude to make skillful predictions on how human-caused climate change may be affecting the AO, or what might happen to the AO in the future.