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Pressure and Temperature

[Image: (28K)]
Reference Weather Map

Current Weather Map

This panel depicts temperature and sea-level pressure contours. This chart is useful for finding fronts and high and low pressure systems.

The solid black contours represent pressure contours (isobars) in millibars. The isobars have a contour interval of four millibars. The wind speed is directly related to the distance between the isobars. The closer the isobars are together, the stronger the pressure gradient, and the stronger the wind.

The colored regions represent the surface temparature. The contour interval of the isotherms is 5 degrees Fahrenheit. From the chart above you can sometimes find warm and cold fronts. Fronts are usually located where temperature changes drastically over a short distance.

When pressure contours are perpendicular to isotherms it means it is either getting warmer or colder. By knowing that winds flow counter-clockwise around a low and clockwise around a high, one can usually see whether there is warming or cooling going on. Usually when the winds are from the south, and you have isotherms (temperature lines) perpendicular to the isobars (pressure lines) you have warm air advection (warm air moving up from the south). The opposite is true if you have winds from the north and isotherms perpendicular to isobars. In that case you have cold air advection (cold air coming in from the north) going on.

For more information on how pressure affects the weather go to our pressure module

temp contours
Terms for using data resources. CD-ROM available.
Credits and Acknowledgments for WW2010.
Department of Atmospheric Sciences (DAS) at
the University of Illinois at Urbana-Champaign.

Dew Point Maps