77ºF

Dense sea fog made for a misty start to Friday

A Dense Fog Advisory was issued for Duval, Nassau, & St Johns counties until 11:00, and for marine waters until 1:00.
A Dense Fog Advisory was issued for Duval, Nassau, & St Johns counties until 11:00, and for marine waters until 1:00.

JACKSONVILLE, Fla. – Dense sea fog rolled onshore late Thursday night, reducing visibilities around town to less than three miles. A Special Weather Statement was issued by the National Weather Service warning residents to expect visibilities between 1 and 3 miles. A Dense Fog Advisory was eventually issued for Nassau, Duval and St Johns Counties until 11:00am for reduced visibilities to less than a quarter of a mile.

Our marine waters are under a Dense Fog Advisory until 1:00pm for reduced visibilities, in many cases down to zero. The fog over our waters will be much more persistent today, and could stick around into the early afternoon hours. Dense Fog Advisories are issued when widespread reduction in visibilities to less than a quarter of a mile are expected.

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.  The mild weather pattern we've seen lately, with unusually warm afternoon and significant cool downs at night lead to 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.

Warming temperatures allow fog to dissipate, but that will be a challenge for us today, as we are shielded by clouds and will be slow to warm out of the 60s this morning. After lunch, we will reach the low 70s. 

When driving in fog the Florida Highway Patrol recommends taking the following precautions:

-- Slow Down. Don't drive faster than your vision.

-- Be Cautious. Fog can become thicker without warning and without being noticed until it is too late to react.

-- Increase Following Distance. Ensure enough reaction time and stopping distance.

-- Use regular low-beam headlights.

-- Use windshield wipers and defroster as necessary to maximize visibility.


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