Update to 6.3.0:

• Close to 30 new functions, including (but not limited to):
• Butterworth bandpass filter
• Calculation of potential vorticity and temperature
• K-means clustering via the Hartigan and Wong AS-136 algorithm
• Vertical interpolation routine for WRF ARW variables
• "Regular expression" (regex) string matching
• Getting the unique values in an array
• Routines for coloring streamlines based on a scalar field (contribution from Alan Brammer, UAlbany)
• Improvements to NCL's handling of advanced file structures (NetCDF-4 and HDF5 groups, for example)
• Improvements and updates to the GRIB 1/2 readers
• Speed-up for multiple calls to the "fbinrecread" function
• More options on the appearance of polyline and polygons overlaid on maps
• Many bug fixes

For full details, please see: http://www.ncl.ucar.edu/current_release.shtml