This panel shows the 850 mb forecasted fields for geopotential height, temperature 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 purple 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.
Temperature 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. Temperatures are given in degrees Celsius with an interval of 5 degrees Celsius between temperature contours, also called isotherms.