I’ll start today with one more look, on today’s map, at high-altitude air pressure over Antarctica. This nice compact shape of the blue zone, with no irregularities on the border, is what we have come to expect for this region. The cavity that recently developed (see CL#2158 on Mar 15), causing a spectacular temperature anomaly, can be thought of as shocking, or at least exciting, or purely an aberration with no lasting effect:
The blue zone in the Arctic, and surrounding green zone as well, is an entirely different matter. Irregularities come and go practically every day. Today is typical for both blue and green zones. The big cavity we saw yesterday that resembled the one in Antarctica and seemed ready to expand has instead tightened up a bit. Sea level pressure may have helped by pulling back instead of expanding outward. The overall anomaly picture–netting warm ones and cold—has changed very little, and so also the relatively low number (+0.7C on the next map) for the Arctic region:
Here are the other maps. I will probably be showing sea level pressure maps more often because the changes recorded do seem to have an important influence on the daily outcome for the high-level configuration, which in turn sets off other critical high-level changes that ultimately affect anomaly production in significant ways.
Carl