Select forecast variable then hours ahead to view the chart.
Shows the geopotential height of the 500mb level.
The charts provide a convenient way of viewing the output from all of the members of the GEFS ensemble model. Each "stamp" represents the output for a given time from one of the members.
The 16 day model updates 4 times per day 07:15 GMT, 13:15 GMT, 19:15 GMT, 01:15 GMT