First polar low of 2015/16 season

Our good friend at the Norwegian Met Office in Tromsø, Gunnar Noer, just told me that they observed the first polar low (with an impact on Norway) this season a few days ago. Here’s a satellite image taken at 18:21 on 26 October 2015:

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The polar low is clearly visible just north of northern Norway. At 20:00 UTC the polar low is more developed:

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It’s also clear that the polar low formed in a cold air outbreak well north of the well polar front (the region that separates cold air in the north from warm air in the south), which is one of the main characteristics of polar lows.

I also found an image of satellite-derived surface wind speeds from the ASCAR radar (click image for higher resolution):

pl_ascat_cropped

This shows that the polar low produced fairly strong winds. There’s plenty of other interesting features as well (as in pretty much every satellite image):

  • A jet along the sea ice edge just north of Iceland, probably due to the high mountains of Greenland. It’s more common to get jets in northerly flow in this region.
  • The left-side jet off the northern tip of Novaya Zemlya, also due to topography. Left-side jets are normally stronger than right-side jets because flow towards a barrier creates a small-scale high pressure anomaly in front of the barrier, and this strengthens the jet.
  • The strong southerly flow along the coast north of southern Norway, also a left-side jet.
  • The strong winds along the polar front, which isn’t unusual in any way.