WW2010
University of Illinois

WW2010
 
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Online Guides
 
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> reading maps
 
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Reading Maps
 
  introduction
 
  utc conversions
 
  temp conversions
 
  surface obs
 
> surface maps
 
  upper air obs

Surafce Maps
 
  obs, isobars, radar
 
  obs, isobars, ir sat
 
  temp contours
 
  temperatures, winds
 
  dew point reports
 
  dew points, winds
 
  24 hour totals
 
> analysis pairs

Analysis Pairs
 
  press & temp
 
> dew point
 
  weather
 
  wind
 
  mixing ratio
 
  moist. convergence
 
  temp. advection
 
  dew point advect
 
  3hr dew pt & wind
 
  3hr temp & wind
 
  3hr press & wind
 
  frontogenesis

User Interface
 
  graphics
> text

NOTE: We've guessed that you're not using a client that supports colored tables and have tried to compensate. Low graphics mode looks much better on clients that do... we recommend switching to Netscape 3.0 or Microsoft Internet Explorer.
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Pressure and Dew point
surface analysis pairs


Example Pressure and Dew point Distribution

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

The solid white 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 dashed green lines represent lines of equal dew point (isodrosotherms). The contour interval of the dew point contours is two degrees Fahrenheit. From the map above you can sometimes find warm fronts, cold fronts, and drylines. Fronts are usually located where the dew point changes drastically over a short distance.

A dryline is also an area where dew point changes dramatically over a short distance. This image is a rare example of a very strong dryline (coldfront) across the Midwest. Dew points dropped over twenty degrees behind the front within a matter of a few hours. This preceded the tornado outbreak on July 2, 1997 that hit parts of Michigan, Indiana and Ohio.

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



press & temp
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.

weather