About This Product
The 500 millibar (mb) map plots a variety of information collected by weather balloons and represents atmospheric conditions at an altitude of approximately 5,500 meters (18,000 feet). The map displays:
- The air temperature (degrees Celsius) in red contours, at 2°C intervals.
- The height of the 500 mb level (meters) in black contours, at 60-meter intervals.
- Wind (knots) — Wind barbs are displayed in a grid. The wind barb is an "arrow" that depicts the wind speed and direction. The "feathers" of the arrow indicate the wind speed while the blank end of the arrow indicates the direction the wind is blowing toward. In addition, regions with wind speeds above 40 knots are shown as blue contours at 10-knot intervals and shaded blue, or shaded purple if above 100 knots.
This map is updated hourly. For more details, visit the NWS Storm Prediction Center's Mesoscale Analysis website.