WW2010
University of Illinois

WW2010
 
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Online Guides
 
  introduction
 
> meteorology
 
  remote sensing
 
  reading maps
 
  projects, activities

Meteorology
 
  introduction
 
  air masses, fronts
 
  clouds, precipitation
 
  el nino
 
  forces, winds
 
  hurricanes
 
  hydrologic cycle
 
  light, optics
 
> midlatitude cyclones
 
  severe storms
 
  weather forecasting

Midlatitude Cyclones
 
  introduction
 
  definition
 
  associated winds
 
  air masses
 
  on satellite images
 
> upper air features

Upper Air Features
 
  geopotential height
 
  troughs
 
  ridges
 
  wave amplification
 
  rising motion
 
  steering level
 
  jet stream
 
  jet streaks
 
  vertical motions
 
  mid-level moisture
 
> wind vectors

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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Wind Vectors
indicate wind direction and speed

The black arrows plotted on this image are wind vectors. These vectors indicate direction and intensity of the wind. The vectors point in the direction to which the wind is blowing and in this image, winds are primarily blowing from west to east. Intensity of the wind is conveyed through the size of the vector. The longer the arrows, the stronger the winds.

For example, wind vectors in the vicinity of the blue arrow are longer than those near the green arrow. This means that by the blue arrow, the winds are stronger, than by the green arrow. Wind vectors are also useful in finding regions of upper level convergence and divergence, which indicate regions of upward and downward motion. Upward motion is typically associated with clouds and precipitation.

Below is an ETA Model forecast panel for 300 mb winds and geopotential heights (white contours). The color filled regions indicate wind speed in knots and is color coded according to the legend at the bottom of the image. The shades of blue indicate winds less than 60 knots, while winds greater than 100 knots are given in shades of red.

[Image: upper air forecast panel (21K)]

The wind vectors (red arrows) are much smaller in the blue regions, where the winds are relatively weak, and largest in the red, which is the region of strongest winds. The ribbon of strongest winds (green, yellow and red colors) is called the jet stream with a jet maximum, or jet streak located along the east coast.

Notice how the wind vectors are aligned generally parallel to the geopotential height contours. Once high enough above the earth, the effects of surface friction on wind direction decrease dramatically and consequently, winds flow roughly parallel to the height contours.



mid-level moisture
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.

Severe Storms