I see your current Settings.php has $SITE['NWSforecasts'] = array( // for the advforecast2.php V3.xx version script
// use "Zone|Location|Point-printableURL", as entries .. first one will be the default forecast.
"COZ085|Colorado Springs,CO|http://forecast.weather.gov/MapClick.php?lat=38.92431&lon=-104.72045606489473&unit=0&lg=english&FcstType=text&TextType=2",
"COZ081|Woodland Park,CO|http://forecast.weather.gov/MapClick.php?lat=38.99388&lon=-105.05692943199966&unit=0&lg=english&FcstType=text&TextType=2",
"COZ083|Canon City,CO|http://forecast.weather.gov/MapClick.php?lat=38.44098&lon=-105.24244796499966&unit=0&lg=english&FcstType=text&TextType=2",
"COZ085|Manitou Springs,CO|http://forecast.weather.gov/MapClick.php?lat=38.85971&lon=-104.91719883399969&unit=0&lg=english&FcstType=text&TextType=2",
"COZ082|Pike's Peak Summit,CO|http://forecast.weather.gov/MapClick.php?lat=38.84054&lon=-105.04441604199968&unit=0&lg=english&FcstType=text&TextType=2",
"COZ040|Denver,CO|http://forecast.weather.gov/MapClick.php?lat=39.73915&lon=-104.98469734299971&unit=0&lg=english&FcstType=text&TextType=2",
"COZ035|Estes Park,CO|http://forecast.weather.gov/MapClick.php?lat=40.3772&lon=-105.5217&unit=0&lg=english&FcstType=text&TextType=2",
"COZ032|Breckenridge,CO|http://forecast.weather.gov/MapClick.php?lat=39.4816&lon=-106.0383&unit=0&lg=english&FcstType=text&TextType=2",
"COC097|Aspen,CO|http://forecast.weather.gov/MapClick.php?lat=39.1911&lon=-106.8175&unit=0&lg=english&FcstType=text&TextType=2",
);
which seems to work just fine.
When you added a new entry, did you remember the opening and closing double-quote marks followed by a comma?
If not, then it would be a PHP syntax error in Settings.php, and since that is included in ALL the wx...php pages, your site would be 'down' until the syntax error is corrected.