On July 7, 2015, the US National Weather Service implemented a new set of icons for
weather conditions reporting, and a new 6-hour icon dynamically created when there are
changing conditions during the 12 hour forecast.  To do this, a new script (DualImage.php)
was created to blend two images together from image templates (in forecast/icon-templates)
and a resulting image displayed to the browser.

An updated advforecast2.php V4.00 (6-Jul-2015) was released to support the dual-image 
function.

The following base images were added to the NWS set for the July 7,2015 DualIcon NWS forecasts
in forecast/images/ subdirectory:

hur_warn.jpg
hur_watch.jpg
nsnip.jpg
nsnip10.jpg
nsnip100.jpg
nsnip20.jpg
nsnip30.jpg
nsnip40.jpg
nsnip50.jpg
nsnip60.jpg
nsnip70.jpg
nsnip80.jpg
nsnip90.jpg
nwind_bkn.jpg
nwind_few.jpg
nwind_ovc.jpg
nwind_sct.jpg
nwind_skc.jpg
snip.jpg
snip10.jpg
snip100.jpg
snip20.jpg
snip30.jpg
snip40.jpg
snip50.jpg
snip60.jpg
snip70.jpg
snip80.jpg
snip90.jpg
ts_nowarn.jpg
ts_warn.jpg
ts_watch.jpg
wind_bkn.jpg
wind_few.jpg
wind_ovc.jpg
wind_sct.jpg
wind_skc.jpg