500 mb Height Contour
This is a contour plot of 500 mb height in meters with a interval of 60
meters. The 500 mb level is often refered to as the steering level as most
weather systems and precipitation follow the winds at this level. The winds
follow the height contours and generally run from 30 to 100 knots. The
speeds can be roughly estimated from the 300 mb winds as roughly 2/3rds
their magnitude. This level averages around 18,000 feet above sea level and
is roughly half-way up through the weather producing part of the atmosphere
called the troposphere.
500 millibar plots are useful for forecasting. Click on this
one for a larger view.