As of Wednesday morning, dense fog enshrouded the city of London.
The thick fog rolled into the region around midnight local time and lasted through mid-morning, creating heavy traffic delays during the morning commute.
For five hours, the city had zero visibility conditions, and for nearly eight hours, visibility was down to 1/8 mile.
By Wednesday afternoon, more than 800 arriving and departing flights were cancelled or delayed at London Heathrow Airport, according to FlightStats data.
While this time of year is favorable for fog across the Northern Hemisphere due to longer nights and more time for morning fog to form, weather conditions in the city late Tuesday evening were prime for fog formation.
"Clear skies and calm winds are the main causes of fog," said AccuWeather Meteorologist Dan DePodwin said. "Wind yesterday was out of the southeast so that helped bring moisture to the area."
Moisture, clear and calm skies are the perfect combination for this kind of all-encompassing fog.
London is not expected to have another fog incident again this week, but instead some stormy weather is in store for the city.
This aerial photo captured by the London Metropolitan Police helicopter crew, on Twitter as @MPSinthesky, shows everywhere but central London enshrouded in fog.
Fog surrounds the city of London. Photo courtesy of Twitter user @TheDJCull.
Canary Wharf is enclosed by fog with only the tops of buildings visible. Photo courtesy of the London Metropolitan Police helicopter crew.
This part of London is almost unrecognizable due to the heavy fog, photo attributed to the London Metropolitan Police helicopter crew.
Relief is on the way for portions of the Plains that are in the grips of the ongoing drought.
A tropical wave west of the Cape Verde Islands looks like it could be the next named tropical storm in the Atlantic Basin.
It was a rather active past few days with tornadoes, flash flooding, and damaging winds targeting many communities.
A pair of tropical threats will target areas from China and Taiwan to Guam this week.
Television meteorologists and weather reports have the responsibility to provide the public with potentially life-saving information, even if it requires the interruption of a popular television program.
In the icy waters of the Bay of Exploits in northern Newfoundland, a Canadian couple on an innocent boat ride were put in a dangerous situation as one of the region's massive icebergs suddenly crumbled.
July 29th is historically a rainy day in Waynesburg, PA. It all began in 1878 when a farmer casually told drug store clerk William Allison that it always seemed to rain on July 29th in this southwestern PA town. The clerk made a note of it and started keeping a yearly tabulation. July 29th, 2001 was the 104th rainfall in the past 124 years on this date.
Mt. Washington, NH (1989)
34 degrees with a 45-mph wind gust (minus 6 degrees wind chill temperature).
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A total of 2" of rain in 40 minutes (10 miles west of Lafayette).