LINES:

For this class of graphics, solid black lines represent isobars which are defined as lines of constant pressure. In this plot the isobars represent the pressure at sea level. Lines are drawn every 2 millibars (mb). Thin blue lines represent areas of equal temperature called isotherms. They depict the temperature at the 925 mb atmospheric pressure level and are labeled in four degree Celsius increments. The intervals may be different depending on the product you are viewing therefore it is important to look at the line interval legend at the bottom right of the plot.

COLORS:

Background color represents the air temperature at the 925 mb atmospheric pressure level in degrees Celsius. The color-bar located at the bottom of the plot identifies the temperature for each shading of color. Thin blue lines separate colors on the map and represent areas of equal temperature.

WIND BARBS

Evenly spaced on the map are wind barbs that indicate the strength and direction of the wind 10 meters (m) above the surface.

1 kt ~ 1.15 mph ~ 1.85 km/hr

WHY IS THIS IMPORTANT?

Surface maps give forecasters a general idea of the state of the atmosphere near and at the surface. Since we live on the Earth's surface the conditions such as temperature and wind strength directly impact our lives and plans. It is important to know what the current surface conditions are and how they will change in the future.

The sea level pressure distribution identifies regions of high and low pressure and the strength of the surface winds. Isobars are directly related to the wind speed. The closer isobars are to one another the stronger the wind. Isotherms that are closely packed signal the location of fronts . Monitoring surface maps over time, using a loop of plots, can be used to help determine how weather systems will move and intensify/dissipate in the future.