JACKSONVILLE, Fla. – Heavy fog is covering areas in several northeast Florida and southeast Georgia counties Saturday morning, according to the National Weather Service. A Dense Fog Advisory has been issued for Southeast Georgia's coastal waters for today. The Dense Fog Advisory is in place until 10:00am, when clearing is expected as temperatures warm. Expect reduced visibilities along hwy 17, bridges, and along I-95. Counties under the Dense Fog Advisory include Hamilton, Suwannee, Columbia, Baker, Unin, Bradford, Clay, Gilchrist, Alachua, Putnam, Marion, Echols, Clinch, coastal Glynn, and coastal Camden counties. Southeastern Georgia's marine waters out to 20 nautical miles are also under a Dense Fog Advisory until 11:00am, and coastal fog may linger well into the late morning hours today.
The National Weather Service reports some areas throughout the morning may have visibility of less than one quarter mile, due to the dense fog.
"Expect persistent dense fog over our coastal waters this morning, with visibilities reduced to less than a quarter of a mile. The fog is anticipated to be a factor over bodies of water through the mid morning hours. Bridges may also be foggy for quite a while today," said meteorologist Rebecca Barry.
Fog forms when the temperature drops within a couple of degrees of the dew-point, 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.
Motorists are urged to use extreme caution this morning when heading out on the roadways. The National Weather Service recommends drivers slow down, use low beam headlights and leave plenty of distance between you and other drivers to avoid collisions.
The marine Dense Fog Advisory will remain in effect until 10 a.m. Saturday.