On today’s weather maps we are getting a wonderful demonstration of the power of the pattern of differences in high-altitude air pressure to significantly influence the pattern of anomalies in Earth’s air temperatures at the surface, which will be displayed in the pictures below. There must be a regular link between two such disparate phenomena, and in my mind that link is best revealed by taking changes in the pattern of jetstream strength and location into consideration. The jetstream pattern will at all times be dominated by and exist in correspondence with the upper air pressure pattern. Today the upper air pressure pattern in the northern hemisphere is highly irregular, thereby causing irregularities of an extraordinary nature in all three of the main jetstream pathways. (Their basic relationship was described in more detail in CLs #1662-3 on April 22-23.)
As discussed more recently, the jetstream pathways, wherever they happen to be, have their own strong effect on the courses taken by members of another kind of airborne stream existing at the same altitude, whenever the two streams come in contact, which is often. These other streams are composed of large quantities of precipitable water which originated at tropical surfaces before being lofted to the same altitude inhabited of the jetstreams. The normal pathways taken by these streams, once they are aloft, is always in the direction of the poles, taking them directly into the territory where jetstreams prevail and can have a dominating influence over their pathways and other behavior, including rainfall and the like.
The high-flying streams of PWAT, in turn, have a direct influence on air temperatures down at the surface, all because of their abilty to provide a goodly amount of greenhouse-type energy radiation which heads down to the surface. Once there it adds on to any amount of similar energy that is normally and more regularly received from an assortment of more ambient sources. The overhead streams keep coming and going, fairly often but not on any particular schedule, and when they do come they all have their own way of spreading out the distribution of either more or less of their greenhouse radiation power, a factor that ultimately determines the relative strength of any warming anomaly. The main point is that all of the necessary links enabling the connection between high-altitude air pressure and surface air temperatures are real phenomena, basically repetitive in action, yet always tending toward changes of some sort. Beneficially to us, they are all being instrumentally recorded day after day.
This first picture is just a current overhead view of the NH air pressure pattern that is generally in play at levels of altitude where jetstreams exist. This one for today is highly unusual in overall shape and shows a distinct lack of any normal amount of internal coherence:
In this next picture we see a full global representation of the same pattern, with the outer edges of it now all lined up as a further convenience. We want to make comparisons taken from the map that immediately follows, which depicts all the major temperature anomalies around the planet today:
Focus on the large bulges in the wavy transition between green and red near the top over the upper map, then see how each of those bulges corresponds with a warm anomaly shown in the lower map. The very large bulge on the right corresponds with the large anomaly we were looking at yesterday, with its several connections to PWAT streams. The large cold anomaly in the center of North America exists as a consequence of having a temporary absence of any PWAT stream passing over and adding radiation. Today’s jetstream pattern is not shown, in the interest of brevity, but is very much involved in shaping all of the PWAT stream bed pathways, also not shown, that are overlying the warm anomalies that are shown. (If you open this today you can go to “live” links and see all those related maps.) On the above maps you can also check out the bulges and the corresponding anomalies in the southern hemisphere, where the effect tends to be clearest on the limited amount of land area. Ocean surface waters in that part of the globe have quite a large and different kind of impact all their own on air temperatures, now in a cooling mode.
Carl