A report on Fog and Cloud

View from Blassenstein mountain near Scheibbs (Lower Austria) to the west, with fog over Erlauf valley and Danube
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A massive fog bank over Twentynine Palms, California, covers the entire city as it begins to rise and join the clouds above it.
Stratocumuliform cloudscape
A foggy Aura River in Turku, Finland
Tropospheric cloud classification by altitude of occurrence: Multi-level and vertical genus-types not limited to a single altitude level include nimbostratus, cumulonimbus, and some of the larger cumulus species.
Minute droplets of water constitute this after-dark radiation fog, with an ambient temperature of -2 C. Their motion trails are captured as streaks.
Cumulus humilis clouds in May
A close-up view of water droplets forming fog. Those outside the camera lens's depth of field appear as orbs.
Windy evening twilight enhanced by the Sun's angle, can visually mimic a tornado resulting from orographic lift
Advection fog layer in San Francisco with the Golden Gate Bridge and skyline in the background
Nimbostratus cloud producing precipitation
Heavy fog on a road near Baden, Austria
Cirrus fibratus clouds in March
Light fog reduces visibility on a suburban street, rendering the cyclist very hazy at about 200 m. The limit of visibility is about 400 m, which is before the end of the street.
Stratocumulus over Orange County.
Sutro Tower casts a 3-dimensional fog shadow
Stratocumulus cloud
Morning freezing fog in Elko, Nevada
Cumulus humilis clouds
Pogonip fog in Virginia City, Nevada, from an early 20th-century postcard
Cumulonimbus cloud over the Gulf of Mexico in Galveston, Texas
Tree in field during extreme cold with frozen fog
High cirrus upper-left merging into cirrostratus and some cirrocumulus upper right
Ice fog on Pyhäjärvi, Tampere during sunset.
A large field of cirrocumulus
Fog rolls into Seattle from the sea
Sunrise scene giving a shine to an altocumulus stratiformis perlucidus cloud (see also 'species and varieties')
Sea fog or "fret" encroaching on Brighton Pier
Altostratus translucidus near top of photo merging into altostratus opacus near bottom
Sea fog in the Arctic Ocean near the island of Jan Mayen
Cumulus humilis clouds over Jakarta, Indonesia
Maple tree with red leaves in the morning mist, in western Estonia
Stratocumulus stratiformis perlucidus over Galapagos, Tortuga Bay (see also 'species and varieties')
A fog on the field of the Leppälahti ja Kuivaniemi villages in Kuopio, Finland
Stratus nebulosus translucidus
Fog hovering over the valleys surrounding La Silla Observatory.<ref>{{cite web|title=Sunset Panorama at La Silla|url=http://www.eso.org/public/images/potw1544a/|work=eso.org|url-status=live|archive-url=https://web.archive.org/web/20151128073056/http://www.eso.org/public/images/potw1544a/|archive-date=28 November 2015}}</ref>
Deep multi-level nimbostratus cloud covering the sky with a scattered layer of low stratus fractus pannus (see also 'species' and 'supplementary features' sections)
Fog surrounding skyscrapers in the Melbourne city centre
Cumulus humilis and cumulus mediocris with stratocumulus stratiformis perlucidus in the foreground (see also 'species and varieties')
Light fog over Taipei, Taiwan with Taipei 101 in the background
Towering vertical cumulus congestus embedded within a layer of cumulus mediocris: Higher layer of stratocumulus stratiformis perlucidus.
Fog in London with the Palace of Westminster in the background
Progressive evolution of a single cell thunderstorm
Dense fog over Indian subcontinent, captured by NASA's Aqua satellite in December 2012
Isolated cumulonimbus cloud over the Mojave Desert, releasing a heavy shower
Fog partially obscuring a mountain in Tirupati in the India summer.
Altocumulus lenticularis forming over mountains in Wyoming with lower layer of cumulus mediocris and higher layer of cirrus spissatus
Example of a castellanus cloud formation
Cumulus mediocris cloud, about to turn into a cumulus congestus
A layer of stratocumulus stratiformis perlucidus hiding the setting sun with a background layer of stratocumulus cumulogenitus resembling distant mountains.
Cirrus fibratus radiatus over ESO's La Silla Observatory
Altocumulus stratiformis duplicatus at sunrise in the California Mojave Desert, USA (higher layer orange to white; lower layer grey)
Cumulus partly spreading into stratocumulus cumulogenitus over the port of Piraeus in Greece
Cumulonimbus mother cloud dissipating into stratocumulus cumulonimbogenitus at dusk
Cirrus fibratus intortus formed into a Kármán vortex street at evening twilight
Global cloud cover, averaged over the month of October 2009. NASA composite satellite image.
Lenticular nacreous clouds over Antarctica
Noctilucent cloud over Estonia
Joshua Passing the River Jordan with the Ark of the Covenant (1800) by Benjamin West, showing Yahweh leading the Israelites through the desert in the form of a pillar of cloud, as described in
Stratocumulus stratiformis and small castellanus made orange by the sun rising
An occurrence of cloud iridescence with altocumulus volutus and cirrocumulus stratiformis
Sunset reflecting shades of pink onto grey stratocumulus stratiformis translucidus (becoming perlucidus in the background)
Stratocumulus stratiformis perlucidus before sunset. Bangalore, India.
Late-summer rainstorm in Denmark. Nearly black color of base indicates main cloud in foreground probably cumulonimbus.
Particles in the atmosphere and the sun's angle enhance colors of stratocumulus cumulogenitus at evening twilight
Total cloud cover fraction averaged over the years 1981-2010 from the CHELSA-BIOCLIM+ data set

Fog can be considered a type of low-lying cloud usually resembling stratus, and is heavily influenced by nearby bodies of water, topography, and wind conditions.

- Fog

Conductive, radiational, and evaporative cooling require no lifting mechanism and can cause condensation at surface level resulting in the formation of fog.

- Cloud
View from Blassenstein mountain near Scheibbs (Lower Austria) to the west, with fog over Erlauf valley and Danube

4 related topics with Alpha

Overall

This graph shows the maximum percentage, by mass, of water vapor that air at sea-level pressure across a range of temperatures can contain. For a lower ambient pressure, a curve has to be drawn above the current curve. A higher ambient pressure yields a curve under the current curve.

Dew point

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Temperature to which air must be cooled to become saturated with water vapor, assuming constant air pressure and water content.

Temperature to which air must be cooled to become saturated with water vapor, assuming constant air pressure and water content.

This graph shows the maximum percentage, by mass, of water vapor that air at sea-level pressure across a range of temperatures can contain. For a lower ambient pressure, a curve has to be drawn above the current curve. A higher ambient pressure yields a curve under the current curve.
Graph of the dependence of the dew point upon air temperature for several levels of relative humidity.

In the air, the condensed water is called either fog or a cloud, depending on its altitude when it forms.

Clouds, formed by condensed water vapor

Water vapor

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Gaseous phase of water.

Gaseous phase of water.

Clouds, formed by condensed water vapor
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Evidence for increasing amounts of stratospheric water vapor over time in Boulder, Colorado.
MODIS/Terra global mean atmospheric water vapor in atm-cm (centimeters of water in an atmospheric column if it condensed)
Cryogeyser erupting on Jupiter's moon Europa (artist concept)
Artist's illustration of the signatures of water in exoplanet atmospheres detectable by instruments such as the Hubble Space Telescope.

The condensation of water vapor to the liquid or ice phase is responsible for clouds, rain, snow, and other precipitation, all of which count among the most significant elements of what we experience as weather.

Fog and clouds form through condensation around cloud condensation nuclei.

Stratus undulatus clouds during a rainy day.

Stratus cloud

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Stratus undulatus clouds during a rainy day.
A cirrostratus cloud
Stratocumulus cloud

Stratus clouds are low-level clouds characterized by horizontal layering with a uniform base, as opposed to convective or cumuliform clouds that are formed by rising thermals.

These clouds are essentially above-ground fog formed either through the lifting of morning fog or through cold air moving at low altitudes over a region.

Different air masses that affect North America, as well as other continents, tend to be separated by frontal boundaries.

Warm front

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Density discontinuity located at the leading edge of a homogeneous warm air mass, and is typically located on the equator-facing edge of an isotherm gradient.

Density discontinuity located at the leading edge of a homogeneous warm air mass, and is typically located on the equator-facing edge of an isotherm gradient.

Different air masses that affect North America, as well as other continents, tend to be separated by frontal boundaries.
A surface weather analysis for the United States on October 21, 2006. Note the warm front in the northwest Gulf of Mexico.

Fog can also occur preceding a warm frontal passage.

As it cools, any water vapor that is present will condense and form extensive cloud cover.