Examples of Various 500mb Patterns

The light blue lines are isobars, or lines of constant pressure. The numbers printed on the isobars are the height of the isobaric pressure surface (in meters). More details to the other symbols are given in the guide link.

Typical Weak Stagnant Summer Pattern

Sep 7 2012 East Wind (Notice the Finger pointing to the West)

Mar 31 2013: A very unusual Pattern

Which produced an amazing cloudless view in Spring!

Winter time Snow Pattern

Zonal Flow; tightly packed isobars

"Cut-Off" Low

Summer time High Pressure Ridge

Superstorm Sandy Animated loop
Precursor is 3 large low pressure systems Prior to fully Sandy Development