NCEP.aggregate: no visible global function definition for ‘aggregate’
NCEP.gather.gaussian: no visible global function definition for
  ‘download.file’
NCEP.gather.gaussian: no visible global function definition for
  ‘read.table’
NCEP.gather.pressure: no visible global function definition for
  ‘download.file’
NCEP.gather.pressure: no visible global function definition for
  ‘read.table’
NCEP.gather.surface: no visible global function definition for
  ‘download.file’
NCEP.gather.surface: no visible global function definition for
  ‘read.table’
NCEP.interp.gaussian: no visible global function definition for
  ‘download.file’
NCEP.interp.gaussian: no visible global function definition for
  ‘read.table’
NCEP.interp.gaussian: no visible global function definition for ‘sd’
NCEP.interp.pressure: no visible global function definition for
  ‘download.file’
NCEP.interp.pressure: no visible global function definition for
  ‘read.table’
NCEP.interp.pressure: no visible global function definition for ‘sd’
NCEP.interp.surface: no visible global function definition for
  ‘download.file’
NCEP.interp.surface: no visible global function definition for
  ‘read.table’
NCEP.interp.surface: no visible global function definition for ‘sd’
NCEP.track2kml: no visible global function definition for ‘rgb’
NCEP.track2kml: no visible global function definition for ‘col2rgb’
NCEP.track2kml : <anonymous>: no visible global function definition for
  ‘rgb’
NCEP.vis.area: no visible global function definition for ‘heat.colors’
NCEP.vis.area: no visible global function definition for ‘par’
NCEP.vis.area: no visible global function definition for ‘dev.off’
NCEP.vis.area: no visible global function definition for ‘rgb’
NCEP.vis.area: no visible global function definition for ‘rect’
NCEP.vis.points: no visible global function definition for
  ‘heat.colors’
NCEP.vis.points: no visible global function definition for ‘par’
NCEP.vis.points: no visible global function definition for ‘dev.off’
NCEP.vis.points: no visible global function definition for ‘rect’
NCEP.vis.points: no visible global function definition for ‘rgb’
robust.NCEP.interp.gaussian: no visible global function definition for
  ‘download.file’
robust.NCEP.interp.gaussian: no visible global function definition for
  ‘read.table’
robust.NCEP.interp.gaussian: no visible global function definition for
  ‘sd’
robust.NCEP.interp.pressure: no visible global function definition for
  ‘download.file’
robust.NCEP.interp.pressure: no visible global function definition for
  ‘read.table’
robust.NCEP.interp.pressure: no visible global function definition for
  ‘sd’
robust.NCEP.interp.surface: no visible global function definition for
  ‘download.file’
robust.NCEP.interp.surface: no visible global function definition for
  ‘read.table’
robust.NCEP.interp.surface: no visible global function definition for
  ‘sd’
Undefined global functions or variables:
  aggregate col2rgb dev.off download.file heat.colors par read.table
  rect rgb sd
Consider adding
  importFrom("grDevices", "col2rgb", "dev.off", "heat.colors", "rgb")
  importFrom("graphics", "par", "rect")
  importFrom("stats", "aggregate", "sd")
  importFrom("utils", "download.file", "read.table")
to your NAMESPACE file.