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Reading Maps
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> surface maps
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Surafce Maps
  obs, isobars, radar
  obs, isobars, ir sat
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Analysis Pairs
  press & temp
  dew point
> weather
  mixing ratio
  moist. convergence
  temp. advection
  dew point advect
  3hr dew pt & wind
  3hr temp & wind
  3hr press & wind

User Interface
> 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.
Pressure and Weather
surface analysis pairs

Latest Pressure and Weather Distribution

This panel depicts sea-level pressure and current weather. This chart is useful for finding regions of active weather and high and low pressure systems.

The solid white contours represent pressure contours (isobars) in millibars. The isobars have an interval of 4 millibars. The wind speed is directly related to the distance between the isobars. The closer they are together, the stronger the pressure gradient, and the stronger the wind. Low and high pressure systems can also be located from the map above. Low pressure systems are located in the regions of the lowest pressure, while high pressure systems are located in the regions of highest pressure.

The letters found in the above image indicate what type of weather is currently occurring. The table below can be used to help interpret what each letter in the image stands for. To test your knowledge of weather symbols, try the weather symbol quiz.

Common Weather Symbols

T Thunderstorm T+ Severe Thunderstorm R Rain RW Rain Shower
L Drizzle ZR Freezing Rain ZL Freezing Drizzle A Hail
IP Ice Pellets IPW Ice Pellet Shower S Snow SW Snow Shower
SP Snow Pellets SG Snow Grains IC Ice Crystals BD Blowing Dust
BN Blowing Sand BS Blowing Snow D Dust F Fog
GF Ground Fog H Haze IF Ice Fog K Smoke
BS Blowing Spray + Heavy NO SIGN Moderate - light

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

dew point
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.