Not all atmospheric rivers (ARs) reach altitudes that are home to jetstream winds. These rivers carry high concentrations of precipitable water (PW), just like the others, are wind driven, perhaps in a more thorough way, and their contents can sometimes travel for thousands of miles without stopping. They originate from massive amounts of warm water evaporation, rise in continuous streams, are lifted by wind activity to altitudes that remain lower than three miles, start the condensation process at any time, and drop precipitation in intermittent phases as they travel onward. At the same time their PW content is constantly generating greenhouse energy effects along the entire course of travel. The end result of this process is practically identical to the results produced by ARs that are traveling higher up. We have a fine example of a lower one work today, leaving tracks that are well mapped out. We’ll start with a wind trail that is picking up vapor from a source of warm water on the west side of the Gulf of Mexico, moves directly northward through the US and Canada, and eventually ends with a high-speed burst after entering the skies north of Alaska and above the Arctic Ocean:
We do not have closeup images of exactly what “surface” winds are like when they are blowing a couple of miles above the surface, but assume that they follow the same track, being based on the same regular isobar outline of low atmosphere air pressure as displayed on the next map. We also need to assume that wind speed in that zone can be relatively high and also remain relatively steady over long distances, in much the same manner as jetstream winds.
We can be sure this wind is carrying high concentrations of PW because of the way these concentrations show up on this next map, in constant contrast with lower PW totals on either side of the trail over the entire distance:
We also have to look for precipitation, which is a bit puzzling because there isn’t any sign of it until the river contents are over Canada, and then not much more. In a few places we don’t even see clouds. ARs at the jetstream level, in fact, at times behave in the very same way over long stretches of their journey but have more overall open displays of fallout.
There is no doubt at all about the constant production of powerful greenhouse energy effects emanating from the PW content of the river. The very strongest effect is associated with the outburst of high wind speed at the very end of the river, just north of Alaska, which is an interesting development. With magnification, I get an anomaly reading of +12 to 14C in this location.
I also want to show the current map of jetstream winds in the upper-level wind system of this part of the planet. They track a completely different formation of air pressure isobars from the ones we’ve seen below, and thus follow a completely different set of pathways. I can see no sign of contact with the AR we have been studying, which at all times has remained at a lower level, safe from being interfered with by the jets. These jets are, however, very much involved with the movement of other ARs at their own level, two of which are adding warm anomalies over other parts of the US, mainly to several southwestern states and to Florida.
Carl