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

Surface Obs
 
  overview
 
  temperature
 
  weather
 
  dew points
 
  cloud cover
 
  pressure
 
  winds
 
> contours

Contours
 
  introduction
 
  isobars
 
  wind & isobars
 
  isotherms
 
> isodrosotherms
 
  more contouring

User Interface
 
  graphics
> text

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Isodrosotherms
surface maps

A line connecting points of equal Dew Point Temperature is called an isodrosotherm. That means, at every point along a given isodrosotherm, the values of dew point temperature are the same.

Isodrosotherms are represented by dashed green contours. An image of reported dew point temperatures and isodrosotherms has been given below.

The black numbers are station reports of surface dew point temperature in degrees Fahrenheit, which is the unit for dew point temperature in the U.S.. Most other nations of the world use Celsius

The isodrosotherms were generated from the observed values of dew point temperature, and have been plotted at intervals of 5 degrees Fahrenheit. The small green numbers are contour labels, which identify the value of an isodrosotherm (55, 65 degrees Fahrenheit).

For example, high dew point values of greater than 70 have been reported in Iowa, Illinois and southern Michigan and are therefore located south of the 70 degree contour.

In the image below, this surface dew point temperature information has been incorporated into a more complex surface map generated for the same time.

Reported dew points show that a dome of very moist air has pushed its way into Iowa, Illinois, and southern Michigan where dew point temperatures are above 70. Such high dew points usually mean humid and sticky weather conditions.

On the other hand, pleasant weather is found across North Dakota and Minnesota, where dew points are in the 50's and the air is much drier.



isotherms
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.

more contouring