Sunday, May 23, 2021

Summer Threshold switchover, when High's become warm and Low's are sustained by cooler air

 ~It is just about to happen,   after long sojourning Arctic Basin High pressure system  

~Impacts sea ice survival in a big way

    The reasons why cyclones persist more in cooler summer weather are obvious,  they cast a shade from the sun.  In the Arctic it is a bit more complex,  sea ice helps create clouds as well,  more of it causes a cloudier Polar summer. Moist air hitting an ice pack easily fogs up,  fog is a cloud touching the surface.   Onto itself summer sea ice and cyclones are a pair,  so it is not surprising that summer Lows tend to survive longer above ice. But there is a time,  such as now,  when cold Highs and Lows may subsist simultaneously:



  3 CMC surface progs, 23 May 00 UTC,  23/06 and 23/12 UTC +extra 700 mb 23/12 UTC.  All showing a less imposing Arctic Gyre High,  apparently moving towards the Canadian Arctic Archipelago where it will eventually be just South of it,  and a 1008 mb Low over the Arctic Ocean Gyre.   Where it will stymie the sea ice exodus towards Fram Strait,  just Northeast of Greenland.   The 700 mb chart portrays this High and Low as having about the same temperature,  this anticyclone will warm a lot,  because it is allows sunrays through,  opposite to the Low, basking in cold, sustained by sea ice,  cloudy weather.  The split in behaviors is temporal in nature and will revert back opposite coming September.  Clouds are essentially all there is stopping a massive catastrophic sea ice melt.  But this is a "frustrated" but nevertheless end of La-Nina weather cycle,  meaning over all lesser clouds and especially warmer High's significantly warmer by lesser pollution at end of Covid pandemic.   WD May 23, 2021


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