~Hot spring summer for North America, #1 warmest year in history.
~ Is strange, since La-Nina usually cools the planet
Lets take a summary look:
However this repositioning always dries up California, not so good. I would expect a wet UK, not so unusual. The big story is the not so much measured La-Nina, whose effects are in some regions almost completely smothered by the North Pacific warm surface temperature blob. So I'd expect less wet than usual a soggy Ireland Norway and UK a weaker flow from the Southeast would do so.
June July, Beaufort Gyre switchover from a stagnant High to a near permanent cyclone will occur very early in June if not earlier. The reasons for this are La-Nina and greater over all Arctic warming. The dumping of sea ice East of Greenland would be less severe, and the cloud cover provided by an Arctic Low pressure system usually overestimates sea ice melting predictions. The shrinking Polar Vortex will ultimately provide for higher pressure systems to linger on top of the Norther Hemisphere continents, as well as high latitude sea born cyclones, the difference being, with a strong sun the June July High pressures usually provide greater warming, and a drying feedback contributing to further heat, hence anticyclonic dominating the fleeting less vapor rich weaker cyclones. Thus Northern Hemisphere lands will be High pressure prone, leaving the Arctic a haven for cyclones, a place for clouds to be strong in numbers. NW Europe will witness nice clear truer color sunsets more often than usual. Siberia will be in a likewise summer 2020 heatwave as well, the main reason being threefold, one is the invisible La-Nina (less clouds), the weaker flow of warm Atlantic moisture, and the much cleaner air given by the last days of Covid-19 atmospheric de-pollution.
August-September much like 2020, except the CTNP will be close to vanish , not to be found even where the remaining sea ice will survive the summer heat onslaught. But at September end, I expect the first winter High near the North Pole Greenland area. The time for switchover back to winter mode over Beaufort Gyre, will be crucial in saving what is left of the sea ice as well, I think the steady Gyre High will come very late though, not enough to have a greater melt season impact. This period is usually very interesting, because summer rages further South while winter starts at the Pole. The Low and High pressures switching from favoring warm or cold modes get blurred at the climate starting to expand borders. Likewise, hurricanes, end of summer creations, clashed with the beginning of the Polar Vortex for milleniums. These geophysical encounters moved the hurricanes rather rapidly. As a result of dramatic Polar warming they will move less but can cause much more damage, even if landings to ground become less numerous, because lesser longitude wise life is a direct result of a warmer autumn Arctic. At about the onset of the North Pole long night, Greenland, because of its nature of being colder than surroundings, may prompt a steadier High Pressure above the warmed North Atlantic, encouraging hurricanes to hug the America's coast on a slow journey Northeastwards. In contrast, of the North Pacific where a lower sun effect will meet the quasi constant Pacific warm temperature blob, a year round source of strong Arctic 'hurricanes' , the violent cyclones, which in the past has exposed further the grim state of summer Arctic sea ice.
The only thing really unknown is the new state of circulation affairs, what will a non existent really normally perennially cold Polar Vortex world look like? We are about to find out. WD April 25, 2021