WW2010
University of Illinois

WW2010
 
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Reading Maps
 
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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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700 mb Heights and Relative Humidity
model mode

[Image: (60K)]

This panel shows the 700 mb forecasted fields for geopotential height, relative humidity and wind vectors. 700 mb charts depict conditions in the middle troposphere (roughly 3000 meters). This is also referred to as the steering level, since most weather systems are "steered" by the winds at this level.

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 700 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.

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.

In this particular image, the important feature is the high relative humidity air over most of High Plains and Rocky Mountain region as well as the Ohio Valley and Mid-Atlantic coast. When relative humidity is high, expect clouds to be present in these regions.

The higher the relative humidity, the more moist the air, which is vital for the development of clouds and precipitation. 700 mb relative humidities of 70% and greater indicate the likely presence of cloud cover in these regions. Also, the absence of high relative humidity air can help intensify thunderstorms through strong downdrafts caused by cooling due to evaporation.



500 hghts, temps
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.

700 vvel, precip