This might be why.

avoid delays, mariners are advised to plan their trips accordingly. (Fifth District Bridge Branch)*

*Italicized text above and below indicates our comment or paraphrase. Plain text is copied from the Notices to Mariners or other sources given.

Hazardous Navy Exercises off North Florida Coast:
THE FOLLOWING AREAS WILL CONTAIN EXERCISES HAZARDOUS TO SURFACE VESSELS FROM 0000-2359 DAILY BETWEEN 17-23 JAN 11 IN THE FOLLOWING AREAS:
GUNEX AREA AREA BOUNDED BY
"BB/CC" 30-45N 080-32W
30-45N 079-40W
30-37.5N 079-40W
30-34N 080-33W
"31J" 29-20N 079-50W
29-20N 079-40W
29-10N 079-40W
29-10N 079-50W
"27C" 30-00N 081-00W
30-00N 080-50W
29-50N 080-50W
29-50N 081-00W
"26C/26D" 30-10N 081-00W
30-10N 079-40W
30-30N 081-00W
30-00N 079-40W (7th District LNM 03)