Valley drivers might want to leave a little early on their Tuesday morning commute.

The National Weather Service issued an urgent message declaring a dense fog advisory in an area stretching from northern Kentucky through Ohio, to northeast Pennsylvania.

The advisory is in effect until 9 a.m.

Drivers may encounter visibilities of one-quarter to one-half-mile in dense fog and should allow extra distance between their vehicle and the one in front of them in case they encounter visibilities near or at zero from the dense fog.

According to AAA, driving in fog can feel like driving while wearing a blindfold. Objects, such as other vehicles or traffic signals, may not be visible until the last moment – sometimes too late to take proper corrective action.

The two most important safety measures when you are driving in fog are to slow down and turn on your low-beam headlights. By reducing speed, you increase the available reaction time. And driving with your low-beam headlights on helps you to see the roadway more clearly and increases your visibility.

Additional tips from AAA for driving in fog:

Use your windshield wipers to increase your visibility and reduce glare from oncoming vehicles.

If your vehicle is equipped with daytime running lights, you may need to turn on your headlights manually, so your tail lights will also be illuminated.

Avoid sudden stops – and remember that larger vehicles need more distance to slow down or stop.

If you must stop, steer off the roadway as far as safely possible.