Forecast hour: 0 6 12 18 24 30 36 42 48 54 60 66 72 78 84 90 96 102 108 114 120 126 132 138 144 150 156 162 168

Description:
The GFS data are provided through OpenDAP from the NCEP Nomads Server (http://nomads.ncep.noaa.gov), acquired at 06Z and 18Z for the 00Z and 12Z (respectively) forecasts, and plotted using NCL. The dynamic tropopause potential temperature is computed by NCEP on the 1.5 PV unit surface (as is the wind). The 850-hPa relative vorticity is contoured in black for cyclonic (positive) values only from 1.0e-04 to 10.0e-04 s-1.