RALEIGH — The National Weather Service posted a dense-fog advisory for northern parts of the Triangle on Tuesday morning and warned drivers that they might encounter foggy patches elsewhere.

The advisory was placed in effect until 9 a.m. for Orange and Durham counties, and the weather service emphasized caution for drivers on Interstate 40 and 85.

The advisory was lifted for Wake, Franklin and Wilson counties because cloud cover had moved in and prevented fog from forming as widely, forecasters said.

The weather service said drivers should still be cautious, however, because fog could be dense in low-lying areas and around water bodies.