Tell me it's all a very bad dream…

WASHINGTON — The FBI is warning police nationwide to be alert for people carrying almanacs, cautioning that the popular reference books covering everything from abbreviations to weather trends could be used for terrorist planning.

In a bulletin sent Christmas Eve to about 18,000 police organizations, the FBI said terrorists may use almanacs “to assist with target selection and pre-operational planning.”

It urged officers to watch during searches, traffic stops and other investigations for anyone carrying almanacs, especially if the books are annotated in suspicious ways.

“The practice of researching potential targets is consistent with known methods of al-Qaida and other terrorist organizations that seek to maximize the likelihood of operational success through careful planning,” the FBI wrote.

The Associated Press obtained a copy of the bulletin this week and verified its authenticity.

The FBI noted that use of almanacs or maps may be innocent, “the product of legitimate recreational or commercial activities.” But it warned that when combined with suspicious behavior– such as apparent surveillance– a person with an almanac “may point to possible terrorist planning.”

The FBI said information typically found in almanacs that could be useful for terrorists includes profiles of cities and states and information about waterways, bridges, dams, reservoirs, tunnels, buildings and landmarks. It said this information is often accompanied by photographs and maps.

The FBI urged police to report such discoveries to the local U.S. Joint Terrorism Task Force.