81ºF

Dense Fog Advisory for some areas

Clay, Duval, Nassau, Camden and Glynn Counties affected until 10 a.m.

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JACKSONVILLE, Fla. – If you plan to hit the pavement this morning, heading to work or school, you may notice dense fog in some areas.

A Dense Fog Advisory has been issued for some counties in Northeast Florida and Southeast Georgia -- including Clay, Duval, Nassau, Camden and Glynn Counties -- until 10 a.m. Thursday.

Some of those areas are experiencing visibility less than a quarter-mile, due to the dense fog.

The fog is expected to clear around 10 a.m., but drivers need to be vigilant and slow down around school zones, bus stops and busy areas.

Fog forms when the temperature drops within a couple of degrees of the dewpoint, all of the moisture in the air condenses out, in the form of a cloud, at the ground level.

Quiet weather patterns, with consistent broad swings in temperature make for fog prone mornings. The warm afternoon temperatures allow for more absorption of moisture in the atmosphere, making you more likely to see fog when the temperatures cool down and the atmosphere can't hold as much moisture.

Fog dissipates when temperatures warm up. As the temperatures warm, the atmosphere can once again hold a higher capacity of moisture, so the droplets of water that make up the cloud are absorbed into the air.

Many times, fog will be more persistent and linger over large bodies of water, like the ocean or the river. The temperature changes diurnally more rapidly over land than the water, so as the land warm up more quickly, the fog dissipates first over the land.

The National Weather Service issues dense fog advisories when they anticipate the potential for widespread visibilities reduced to less than a quarter of a mile. When visibility on the road is less than a quarter of a mile, that is the threshold for what is considered hazardous to drive in.