By reducing the area of coverage over the Eastern Pacific and Western
Atlantic oceans the WPC will be able to release the analysis approximately
30 minutes earlier, about 1 hour after observation time. The current
domain was defined at a time when the North American analysis was distributed
by facsimile and only one chart could be sent for each analysis time and
this chart needed to meet the needs of a wide variety of users. With
the availability of several different surface analyses from different centers,
it no longer makes sense to delay the data-rich North American analysis
in order to prepare an analysis over a large section of the adjacent Oceans.
See the surface analysis faq for more information.