[angkor]

It's in the next sentence:

"This supersedes the Worldwide Caution dated November 21, 2003. The text of that Caution is being reiterated below to remind U.S. citizens of the continuing threat that they may be targets of terrorist actions and to alert them to the raising of the Homeland Security threat level from Yellow (Elevated) to Orange (High). This Worldwide Caution expires on June 21, 2004."

[JustPiper]

Yes in relation to what "Orange" means in general it goes on to say:

Terrorist actions may include, but are not limited to, suicide operations, hijackings, bombings or kidnappings. These may also involve commercial aircraft and maritime interests, and threats to include conventional weapons, such as explosive devices.

Ridge: Possible attacks could rival 9/11"