WW2010
University of Illinois

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

Forecast Maps
 
  300 hghts, winds
 
  300 hghts, temps
 
  500 hghts, vorticity
 
  500 hghts, temps
 
  700 hghts, humidity
 
  700 vvel, precip
 
> 850 hghts, humidity
 
  850 hghts, temps
 
  1000 convrg & temp
 
  sfc precip, prs, thk

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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850 mb Heights and Relative Humidity
model mode

[Image: 850 mb forecast panel with heights and color-filled relative humdidity field (71K)]

This panel shows the 850 mb forecasted fields for geopotential height, relative humidity and wind vectors. 850 mb charts depict conditions in the lower troposphere (roughly 1500 meters).

Geopotential height approximates the actual height of a pressure surface above mean sea-level and is represented by the solid white contours. The geopotential height field is given in meters with an interval of 30 meters between height lines. The locations of surface cyclones and anticyclones hold similar positions in the 850 mb geopotential height field.

Wind vectors provide information about wind direction and wind speed and are drawn here as tiny white arrows. Wind vectors point towards the direction in which the wind is blowing and the longer the wind vector, the stronger the wind. The unit of magnitude for wind speed as depicted by the wind vectors is meters per second.

In this particular image, the important feature is the presence of high relative humidity air over most of the continental United States. Moisture over these areas will allow the possibility of clouds and precipitation to form. Over Kansas, where the air is relatively dry, clouds will most likely not form.

Relative humidity is represented by the color filled regions and the associated values are indicated by the color code located in the lower left corner of the forecast panel. Relative humidities are given in percent with an interval of 10% between the shaded humidity contours. Humidities of 50% and greater are shaded in varying colors of green, while humidities less than 50% are not shaded. The higher the relative humidity, the more moist the air, which is vital for the development of clouds and precipitation.



700 vvel, precip
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.

850 hghts, temps