The study of the physics, chemistry, and dynamics of the earth's atmosphere

High Pressure Systems High Pressure systems are weather patterns that are known for fair weather. High's form to the east of vorticity minimums on a ridge in a forecast map. High's rotate clockwise with the wind pattern pushing out of the High's center.

Low Pressure Systems

Low Pressure Systems: A low pressure system is a type of weather pattern that most likely happens around a trough on a forecast map and to the east of the cyclone’s vorticity max. Low pressure systems rotate counterclockwise, with a pattern of winds going towards the center of the Low. Depending on the intensity and the low amount of pressure (e.g. 996mb), the Low can produce a significant amount of precipitation.


Vorticity Maximums and Minimums

Vorticity maximums (Vort max) are points on a forecast map that lie normally at or near a short-wave trough. Air parcels in vort max's can usually go as fast as 14.89x10^-5 per second, indicating the description of how short or long the wave is in that particular trough. Vort max's can easily produce Low pressure systems to the east of them. Vorticity minimum's (vort min) are the exact opposite. Vort min's occur near a ridge on a forecast map, with air parcels in the center going as slow as 5.21x10^-5 per second (never negative values). To the east of these vort min's, High pressure systems can easily form here. To access the current Vorticity max's and min's, click on the link, and select either 00Z(UTC) or 12Z(UTC) WRF forecast log, and select any number (e.g. 06, 12, etc).


Grenci, L. (2008, Spring). High and Low Pressure Systems. METEO 101: Penn State University.
Grenci, L. (2008, Spring). Vort Min and Max. METEO 101: Penn State University.

Further Reading

The National Weather Service "Jet Stream" page.
The National Oceanic Atmospheric Administration's Explore Weather page.

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