Top of PageWhy is the visibility only sometimes contained in the forecast?
To help maintain brevity the marine forecast will only include visibility if it is obstructed to the extent that it could potentially impact marine operations. One nautical mile is the threshold that has been determined by most mariners to be the critical threshold for their activities. Visibility, along with the associated obstruction, will be mentioned when it is expected to be one nautical mile or less. For fog alone, visibility is not mentioned in the marine forecast since the visibility statement at the beginning of the forecast states that the presence of fog alone implies visibility less than one nautical mile.
