The United States Weather Maps, September, 1878

Abstract

IN the description of the United States Weather Maps for August, 1878, attention was drawn to the fact (vol. xxii. p. 36) that in that month atmospheric pressure was under the normal over a broad belt going halfway round the globe, extending from the Rocky Mountains across the United States, the Atlantic, Europe, and thence into Asia as far as the valley of the Lena, and the bearing of this abnormal distribution of the pressure on the temperature, winds, and rainfall of this large and important part of the globe was adverted to. In the September following, the U.S. Weather Map for which appears with this notice, great and radical changes in the distribution of pressure took place—such as a change from a large defect from the normal pressure to a large excess above it in the New England States, South Britain, Central Europe, South Africa, and New Zealand; and on the other hand, a change equally striking from a large excess above the normal to a large defect from it over the West India Islands, South Greenland, Iceland, North Britain, and the whole of Southern Asia from the Bay of Bengal to Japan. As it is still premature to speculate on the causes of these enormous changes in the distribution of the mass of the earth's atmosphere and the still more enormous forces called into play in effecting them, we must content ourselves with stating them a little more in detail, and drawing attention to some of the more immediate and striking climatic consequences which followed in their train.