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The air moving away from the High pressure system leaves a “hole” to be filled, so air from above sinks into that “hole”.
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High Pressure Systems

Have you ever seen a weather map with a blue H on it? This blue H means there is a high pressure system over that area of the map. Just what does that mean?

It means that that area has higher pressure then the air around it.

When there is a High above your house, you should expect clear skies and no rain or snow! The way I remember it is that a High will make my spirits high because good weather is on the way.

Last modified April 19, 2009 by Jennifer Bergman.

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Windows to the Universe, a project of the National Earth Science Teachers Association, is sponsored in part is sponsored in part through grants from federal agencies (NASA and NOAA), and partnerships with affiliated organizations, including the American Geophysical Union, the Howard Hughes Medical Institute, the Earth System Information Partnership, the American Meteorological Society, the National Center for Science Education, and TERC. The American Geophysical Union and the American Geosciences Institute are Windows to the Universe Founding Partners. NESTA welcomes new Institutional Affiliates in support of our ongoing programs, as well as collaborations on new projects. Contact NESTA for more information. NASA ESIP NCSE HHMI AGU AGI AMS NOAA