U.S. Homeland Security Secretary Jeh Johnson activated the National Terrorism Advisory System for the first time today.

Under the new system, DHSy will issue bulletins designed to update the public on the changing nature of terrorism threats. The department already issues bulletins to law enforcement agencies about specific cases or types of threats, but the new system is designed to provide more general information to the public about the overall threat environment.

The bulletins would be unlikely to provide specific information about plots, but rather a broader sense of officials’ concerns.

A bulletin might, for example, inform people to expect longer screening lines at public events at times and places when security is ramped up.

“We have witnessed constantly evolving threats across the world, from Garland to the streets of Paris, to San Bernardino,” said Secretary Johnson. “We have also heard repeated calls from ISIL against our citizens, our military and our law enforcement personnel. In light of these persistent activities, the secretary thought it necessary to… share more information with our fellow citizens.” 

David Heyman, a former Homeland Security policy official who advocated eliminating the color code system, welcomed the announcement.

"Given the current threat environment where we clearly understand the tactics of terrorists but have little to no notice of attacks, Secretary Johnson was looking for a way to formally communicate threat information to the public," Heyman said.

"The Secretary wanted a way to do that without raising the alert level, which historically has heightened fear without providing information about how to better protect ourselves, and without simply allowing information to come from leaked sources."

http://www.nbcnews.com/news/us-news/homeland-security-begin-issuing-new-threat-advisories-n480761