All Weather News

A Blanket of Fog

2 Dec 2012, 2:42 pm

Dense fog blanketed parts of the nation early on this morning, and at one point, at least 20 states were seeing Dense Fog Advisories.

This image below, from, was taken back in late May 2012 from Dubai.  The world’s tallest building, the Burj Khalifa, stands at 2,700 ft-high and it uses this to its advantage as it stands well above the cloud layer, which hovers around 400 feet.  The lights from the surrounding buildings is helping to illuminate the thick clouds.

Many locations had their visibilities reduced to around 1/4 mile or less this morning, which made driving and air travel somewhat difficult.  According to the National Weather Service, fog is “water droplets suspended in the air at the Earth’s surface. Fog is often hazardous when the visibility is reduced to ¼ mile or less.”

During the early morning hours, the fog can cause many folks to become distracted or unaware of their surroundings.  With these reduced visibilities, it is a good idea to drive slower than usual and leave extra space between you and the car in front of you. The fog not only impedes vision, but also makes for slicker roads, which reduces your ability to stop quickly. When the fog becomes very dense, there is next to no time to react properly to avoid an accident.  A Dense Fog Advisory is defined as “when fog reduces visibility to 1/8 mile or less over a widespread area.”


Fog blanketed much of the Midwest this morning, and the graphic above shows eight states with fog-related advisories. The green shaded counties are Freezing Fog Advisories.  Temperatures were down in the low 30s in the early morning hours and the abundant moisture combine with the lack of winds, allowed the fog to settle down on surfaces and freeze.  This situation is not good at all for travelers, because icy conditions can form on the roadways in a very thin layer, very similar to black ice.  Freezing Fog is defined by the NWS as “a fog where the droplets freeze upon contact with exposed objects and form a coating of rime and/or glaze.”

Outside our studio, you can see how gloomy the conditions were.


The campus grounds of the University of Iowa look like they were straight out of a scene from a horror movie this morning!  And no, this picture was not taken from a black-and-white camera, it was just THAT foggy at 4am.  As the sun rose and burned off the fog around 10am, the colors returned and the buildings in the distance became visible.  What a difference a few hours make!  The campus grounds look stunning and alive, even though its a Sunday, and most of the students are either sleeping (my first guess) or are away.



The East coast also had to contend with the fog this morning.  Dense Fog Advisories covered 9 states, plus the Washington D.C. area.  While the fog is clearing in the Mid Atlantic, the moisture is creeping into New England.  As the advisories were being lifted from MD, PA and NJ, MA, CT and NH were being placed under Dense Fog Advisories.

It was not a good day to do any morning exercises in Ocean City, MD.  The boardwalk was barely visible and the conditions only started to improve after the late morning hours. Joggers would have had a pretty terrible view early this morning!




How about trying to head down the I-95 corridor through the “City of Brotherly Love”?  Well there were low visibility issues as well in Philadelphia and the surrounding areas.  So if you were thinking of leaving early this morning and beating the weekend rush, well you had to take your time.


And finally, up in New England, Portsmouth, NH had fog even on the coastline.  All these tug boats were docked throughout the evening hours and in the morning, they were the only thing visible.  There is a larger ship ahead of them that is barely visible and, if there were clear skies, you could see the rest of the port.  If dense fog is found to be occurring over a marine area, an advisory for widespread or localized fog would be put up about the reducing visibilities to regionally or locally defined limitations that do not exceed 1 nautical mile.


Well now that the fog has lifted, for the most part, go out and enjoy this wonderful Sunday.  The afternoon will be pleasantly mild across much of the country, from the East coast back to the Midwest, and between the 49th parallel and the Rio Grande.  Here are the amazingly warm temps for today… is this really December?!

These temps are running well above seasonal levels.  We could see high temps nearly 30° warmer than where they should be.  That much warmth can be found in the Northern Plains.  The core of the warmth will be from Nebraska to North Dakota.  Few places will be below average, including the southern tip of Florida, and the western sides of the the Cascades and the Sierra Nevadas.


Take care and have a great week!

Meteorologist Addison Green (twitter @agreenWNTV)

2 responses to “A Blanket of Fog

  1. Well, you would expect the moon in pegiere to make tidal currents stronger. We were paddling from Manhattan down to Sandy Hook and the ebb current, which is normally strong, was really sluggish. On the other hand, the flood current coming back, which is normally weaker than the ebb, was just roaring! for which we were thankful

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