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.