Skip Navigation Links 
NOAA logo - Click to go to the NOAA home page National Weather Service   NWS logo - Click to go to the NWS home page
Climate Prediction Center

CPC Search
About Us
   Our Mission
   Who We Are

Contact Us
   CPC Information
   CPC Web Team

HOME > Monitoring and Data > Monitoring Weather & Climate > Blocking
Observed Northern Hemisphere Atmospheric Blocking Banner

All colored regions in the hovmoller plot below depict regions where the flow is blocked according to the blocking index. The color scheme denotes the strength of the blocked flow as determined from the 500 hPa geopotential height gradient measured from the blocking ridge equatorward (denoted GHGS in blocking index definition). The presence of an intense cutoff low equatorward of the blocking ridge can act to enhance the blocking strength.

Blocking Strength GHGS Observations

500 hecto pascals Geopotential Height and Anomalies


NOAA/ National Weather Service
National Centers for Environmental Prediction
Climate Prediction Center
5200 Auth Road
Camp Springs, Maryland 20746
Climate Prediction Center Web Team
Page last modified: October 22, 2002
Disclaimer Privacy Policy