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Maps to the Masses
Thu May 29, 2003
Listen in RealAudio 
The weather map, like a topographical map, is a two dimensional interpretation of a three
dimensional world. It's a tricky thing to come up with a weather map, but they've been around
for over a century. Hi, I'm Bryan Yeaton for The Weather Notebook.
Around 1900, the basic weather map's format was pretty much set. There were H's for centers
of high pressure, L's for low pressure, and lines of equal pressure, called isobars, drawn
around the highs and lows. However, the maps lacked cold fronts and warm fronts. That's
because scientists hadn't discovered them yet.
It was the so-called Bergen School of Meteorologists, in Bergen, Norway, that conceived the
notion of fronts, of air masses clashing along boundaries. They named these boundaries after
the battlefronts that were then raging in World War I. It has turned out to be a good
comparison, because both in military and meteorological terms, the front is where the action
is.
It took almost 20 years for the United States to accept this European concept, but by 1936,
all official weather maps began to include fronts. However, the public knew little of fronts
then, because there was no such thing as a weathercast on the six o'clock news. It took
television to make cold fronts and warm fronts household phrases; because TV is such a visual
medium, the earliest weathercasters relied on maps to tell their story.
Once TV became more common in the 1950s, the country started getting used to the evening
forecast, and we became familiar with those wavy lines that snake their way across the
country, showing changing weather on a changing weather map.
Thanks today to writer, Bob Henson. Funding is provided for The Weather Notebook by Subaru of
America and by the National Science Foundation.
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