The 12 hour Surface Analysis map shows current weather conditions ... Use of surface analyses began first in the United States, spreading worldwide during the 1870s. Use of the Norwegian cyclone ...

The 48 hour Surface Analysis map shows current weather conditions ... Use of surface analyses began first in the United States, spreading worldwide during the 1870s. Use of the Norwegian cyclone ...

This story appears in the February 2017 issue of National Geographic magazine ... was documented—in Tuscany.” For their map of the United States (above), Hargreaves and Levin chose as their ...