The images in today’s letter are all one day old. I saved them yesterday because the story they tell is so strangely interesting, knowing that by today it will have changed in some ways. The primary focus is on the truly peculiar shape of the jetstream-level air pressure configuration in the Northern Hemisphere, as mapped at the 500hPa level. This pattern of air pressure changes is considerably different from the pattern of high and low pressure changes at sea level, as commonly found elsewhere. The changeover is always completed at an altitude of less than 5000 to 6000 meters, or 3 to 3 1/2 miles—probably not very much less since I don’t recall ever hearing about jetstream winds being found at less than three miles high. Anyway, except for the zone of the tropical belt, the airspace above this level has a demonstrably different wind system from the space below and everything contained in that space (including airplanes) will be influenced accordingly. Keeping in mind the principle that every pattern of configuration completely governs the strength and location of all jetstream wind pathways, this peculiar pattern should pose no exception. Those winds, in turn, always have a profound influence on the behavior of any bodies of precipitable water (PW) that may have entered the airspace, which then respond by the way they influence the temperature of air at the surface below by virtue of their greenhouse effect, which can be considerable.
Jetstream winds always move counter-clockwise in the NH. One major pathway always follows the outer fringe of the “green zone” of air pressure, as depicted, while a separate pathway follows the light blue line that fringes the blue zone. Yesterday’s odd setup will obviously create some complications of a type we don’t usually see. Let’s have a look, this time with a focus on the deep and narrow penetration of the green zone as it pokes its way past Alaska and the wider, block-shaped penetration that reaches over Greenland :
You can always figure out the location of green zone jet wind pathways just by looking at their isobars. In these two situations wind strength is getting all messed up, literally disappearing in the “outcrop” approaching Greenland. How should this picture affect the behavior of major PW concentrations that are actively engaged in both situations? One large stream has risen from Pacific waters, the other from waters in the Caribbean area of the Atlantic. Considerable amounts of PW from both streams, after first being carried off by larger jetstream winds of a more regular type, have eventually found their way into these deviant sidetrack movements, as we see in this image:
One of these heads straight north along the North American coast line, carried by a weakly-constructed jet. When that jet makes a sharp bend and heads south again practically all of the PW it has been carrying is ejected, right into the heart of the polar zone. Nothing unusual about that development. On the Atlantic side a substantial amount of PW has also escaped its jet carrier at a bending point and freely dispersed into a wide open space in the direction or Greenland. The only thing holding it back from still further progress is the square-shaped pathway holding a moderately strong jet on the fringe of the blue zone. This is how things can happen up there, and nobody would know about it without the amazing instruments we have invented. The resulting effect on surface air temperatures is just what one should expect under a proper understanding of greenhouse energy theory:
The warm track that is visible along the Pacific coastline, being over water, is not very prominent, but as soon as the PW remnants journeyed over naturally very dry land or ice their strength became amplified. We then can see how the jet wind on its return journey south, once stripped of its cargo, left a trail of cold anomalies. Curiously, as we see on the last chart, this trail is also marked by a virtually cloudless sky, putting an exclamation point on the lack of PW being carried. On the Greenland side, a fairly heavy input of PW has certainly had considerable leverage over the normally very dry surface air, producing a major warm anomaly with readings of +20C or better in places.
Carl