A rare kind of day for global temperature anomalies. You’ll need to pay special attention to the numbers at the bottom of this map:
First rare note: The entire globe is 0.1C below the baseline average for the day, which goes back a little more than three decades. This is a time period normally associated with a global warming trend of about +0.6C when all days are given equal weight. Today’s negative number is far, far below the norm. Second, the Antarctic Circle average of -8.8C represents an insanely strong dip below normal. Everything in dark blue on the map is around minus 10. Using magnification, I can even see several spots in the minus 28-32 bracket. The Arctic at +1.0C is also below its current average, but only by a degree or so. Third, the difference of 1.4C between the two hemisphere is the greatest I have ever seen. Both polar zones have a great deal of leverage on their respective hemisphere numbers, and thus on the globe as well. The Antarctic is obviously carrying a maximum load of negative anomaly today. It will quickly bounce back, but I expect it to remain pretty much locked in on the negative side for a number of months because of a common feedback process that is now well-established.
The next image lets us compare the differences in high-altitude air pressure configurations between the two polar zones. I would guess that the contrast in “blue zones” a few years ago was seldom as great as what we are now seeing. The way nature does things, a blue zone can only appear when the surface directly below is well-marked with below freezing temperatures. I believe this requirement has seen a trend of progressive decline in recent decades.
Let’s take a quick look at the temperature map to see how the surface in the north is doing today. The only temperatures below freezing are the scattered few that have some shade of blue. Notice how the entire still-frozen center of the Arctic Ocean is now shaded in light green, putting it on the +1 side of zero.
High-altitude air pressure differentials are of critical importance because they govern the positioning and strength of jetstream wind pathways. The pathways identified by the way they track the perimeters of each blue zone and green zone are of elevated importance because of their control over the freedom of movement of precipitable water (PW) concentrations in the upper parts of the non-tropical troposphere. This maps reveals how much these pathways have deteriorated in the north, as opposed to those in the south:
On this final map it is not difficult to see that good-sized volumes of PW are currently making deep penetration of the polar zone in the north while in the south nearly all such movement is being blocked—exactly in locations occupied by jetstream winds.
Carl