About the NCEP MMAB Experimental Coastal Visual Range Guidance
revised April 2, 2004; reviewed April 2, 2004; retired 15 August 2018
The lowest layer visibility products are provided as a post-processed field
direct from the eta model. This field is in m and has been converted to n mi
on the depiction shown at this web page. This visibility field is created by
using an algorithm developed by Stoelinga and Warner (1998) which takes into
account clould liquid water, cloud frozen water, liquid precipitation, and
frozen precipitation. This field was added as a part of an eta implementation
which occurred in April 1998. This algorithm was upgraded in the implementation of July 8, 2003.
The U.S. and Gulf of Mexico depictions are derived from eta-12 fields on the
AWIPS 212 grid and converted to a 0.25 by 0.25 degree lon/lat grid by GRADS. The
Alaska depictions are derived from eta-12 fields on the AWIPS grid 216 and
converted to a GRADS 0.25 x 0.25 degree lon/lat grid. For more information on
the eta model see frequently asked questions about the eta.