Today I can’t resist the idea of loading up the letter with images and cutting the commentary. It’s because I saw something interesting happening at the North Pole and then noticed the very same sequence developing at the other end, not far from the pole. The North Pole has recorded a warming anomaly of a little over +20C for at least one day. The source of all the extra heat can be explained and illustrated with considerable clarity for anyone who understands the regular connection between high-altitude air pressure configuration, jetstream location and behavior, the existence and behavior of equally high-level concentrated streams of water vapor, the way the two types of streams interact, and what can happen to surface air temperatures as a result of all that miles-high activity. Four different maps, twice repeated, will tell almost the very same story with an uncanny degree of similarity. In the south the peak anomaly is a few degrees less warm but the full size of its impact is quite similar. So here we go:
A major jetstream wind pathway, the innermost of three such majors, always follows the track of the pale blue line in the air pressure configuration model:
A well-stocked vapor stream is here observed while being carried along the right side of the jet wind limb that is heading directly over the pole. The sharp bend in the wind pathway weakens the jet and allows the vapor to escape and then spread out. The pole itself is now underlying a total of about 8kg of precipitable water, probably more than four times its average for this day.
The brightest red anomaly just to the right of the pole, backed by 10-11kg of vapor, looks like it may run as high as +23 to 24 degrees. That spot has reported maximum temperatures above freezing for the day while the pole had a high of -1C.
Now we head south and start over. The high-altitude air pressure pattern here, just the opposite of the trend in the north, has begun weakening due to the seasonal warming of temperatures at the surface below.
Jetstream winds following the light blue track now have a sharp bend of their own to negotiate, just like the one in the north, perhaps even tighter. These winds also all move east to west, which in this case is clockwise.
A massive vapor stream heading poleward has found an entry in the looping jetstream pathway. Use magnification to see how deeply it is pushing directly into the coldest parts of the polar zone.
The Antarctic as a whole is now reporting an anomaly of +1.2C, as opposed to the flat and negative numbers that have been common for months on end. This particular breakthrough by an intact vapor stream of high concentration is the primary reason. It may at least be signaling the start of a trend that will soon be more consistent.
Carl