The most successful attempts at influencing weather involve cloud seeding ; they include the fog-and low stratus dispersion techniques employed by major airports, techniques used to increase winter precipitation over mountains, and techniques to suppress hail.

The international cloud classification system is based on the fact clouds can show free-convective upward growth like cumulus, appear in non-convective layered sheets such as stratus, or take the form of thin fibrous wisps, as in the case of cirrus.

These were respectively stratocumuliform and stratiform cloud genera of a newly defined middle height range above stratocumulus and stratus but below cirrocumulus and cirrostratus, with free convective cumulus and non-convective nimbus occupying more than one altitude range as clouds with vertical extent.

When a low stratiform cloud contacts the ground, it is called fog, although radiation and advection types of fog do not form from stratus layers.

Of the two main cloud types in this family, the prefixed genus is stratocumulus ( Sc ), a low altitude cloud of limited convection, and the non-prefixed genus is non-convective stratus ( St ) that usually forms into a comparatively thin layer.

Since nimbus was classified separately from the cumulus, stratus, and cirrus categories during that time, it was usual to refer to it as a nimbiform cloud that comprised its own physical category.

Low stratus clouds usually produce only light precipitation, but this always occurs as the feature praecipitatio due to the fact this cloud genus lies too close to the ground to allow for the formation of virga.

* Genus stratus ( St ): A uniform stratiform layer of low non-convective cloud resembling fog but not resting on the ground.

** Species stratus nebulosus ( St neb ): A featureless veil of low cloud sometimes producing light drizzle ( C < sub > L </ sub > 6 ).

** Species stratus fractus ( St fra ): A ragged broken up sheet of St that often forms in precipitation ( C < sub > L </ sub > 7 ) falling from a higher cloud deck.

Moderate vertical nimbostratus cloud covering the sky with a scattered layer of low stratus fractus in the middle of the upper half of the image.

While fog is a type of stratus cloud, the term " fog " is typically distinguished from the more generic term " cloud " in that fog is low-lying, and the moisture in the fog is often generated locally ( such as from a nearby body of water, like a lake or the ocean, or from nearby moist ground or marshes ).

Fog, like its slightly elevated cousin stratus, is a stable cloud deck which tends to form when a cool, stable air mass is trapped underneath a warm air mass.

If the cirrostratus is broken fibratus it can mean that the front is weak and that stratus rather than nimbostratus will be the rain cloud ( meaning drizzle instead of moderate rain ).

A stratus cloud can form from stratocumulus spreading out under an inversion, indicating a continuation of prolonged cloudy weather with drizzle for several hours and then an improvement as it breaks into stratocumulus.

The low, sharp inversion can lead to areas of persistent stratocumulus or stratus cloud, colloquially known as anticyclonic gloom.

The low, sharp inversion can lead to areas of persistent stratocumulus or stratus cloud, colloquially known as anticyclonic gloom.

Curtis Roads suggests a taxonomy of cloud morphology based on atmospheric clouds: cumulus, stratocumulus, stratus, nimbostratus, and cirrus ; as well as nebulae: dark or glowing, amorphus or ring-shaped, and constantly evolving.

While stratus cloud decks can occasionally reach the interior valleys in July and August, they are very often confined to the coastline during this time.

The low, sharp temperature inversion can lead to areas of persistent stratocumulus or stratus cloud, known in colloquial terms as anticyclonic gloom.

The prefix nimbo-or the suffix-nimbus indicates a precipitating cloud ; for example, a nimbostratus cloud is a precipitating stratus cloud, and a cumulonimbus cloud is a precipitating cumulus cloud.

Low stratus is also of the species nebulosus except when broken up into ragged sheets of stratus fractus.

It is only rarely observed with stratus nebulosus.

Altocumulus is also often seen in a fragmented form behind a frontal system alongside stratus fractus or stratocumulus.

More specifically, the term stratus is used to describe flat, hazy, featureless clouds of low altitude varying in color from dark gray to nearly white.

On a weak warm front, it is common for a stratus to form, rather than the usual nimbostratus.

If it is seen after rain it should clear due to warm front succession, but if this does not occur the stratus must be part of the warm sector of a frontal system ; heavy rain may start again with the arrival of a cold front after several hours of stratus.

The text of hexameter verses, rhymed at end and middle, in the ledger lines is as follows: Subiacet hic stratus, Robert Hallum vocitatus ; Quondam prelatus, Sarum sub honore creatus ; Hic decretorum, doctor pacisque creator ; Nobilis Anglorum, regis fuit ambasciator ; Festum Cuthberti, Septembris mense vigebat ; In quo Roberti, mortem Constantia flebat ; Anno milleno, tricent octuageno ; Sex cum ter deno, cum Christo vivat amoeno.

In summer it is frequently covered with cumulus clouds, especially on rainy days, and in winter stratus clouds and fog often cover the peak.

A distinct social stratus known as kosezes ( Kasazes in Latin, in German Edlinger, noble people ), which were present also in other parts of the Slovene Lands until the High Middle Ages, is thought of having derived from the private army of the Carantanian prince.

The condition is prevalent in many parts of the world where an offshore marine layer of stratus or stratocumulus clouds is common, such as the western coasts of continents — particularly off Peru, Namibia, Western Australia, atlantic Sahara and Northern California, particularly San Francisco.

This species may also result from a continuous sheet of stratus becoming broken up by the wind ( C < sub > L </ sub > 6 ).

Nimbostratus will occur along warm fronts where the slowly rising warm air mass creates nimbostratus and stratus clouds, which are preceded by higher-level clouds such as cirrostratus and altostratus.

Instrument pilots have been advised that Watsonville is occasionally surrounded by non-IFR traffic that ( illegally ) climbs / descends to low stratus layer.

However, only two are seen with altostratus and stratus nebulosus whose uniform structures prevent the formation of a perlucidus variety.

A " cloudy day " usually features a sky filled with stratus clouds obscuring the disk of the sun.

That morning, low stratus clouds overspread much of Oklahoma, with clear skies along and west of a dry line located from Gage to Childress, Texas.

Being familiar with Wegener's earlier work, Bergeron theorized that ice crystals on the tree branches were scavenging vapor from the supercooled stratus cloud, preventing it from reaching the ground.

These velocities are common in convective downdrafts, but are not typical for stratus clouds.

Cumuliform clouds forming in the lower level were given the genus name cumulus, and low stratiform clouds the genus name stratus.

The heavier precipitating clouds, nimbostratus, towering cumulus ( cumulus congestus ), and cumulonimbus, also typically see the formation in precipitation of the pannus feature, low ragged clouds of the genera and species cumulus fractus or stratus fractus.

**** Mutatus mother clouds: Altocumulus, nimbostratus, stratus.

:::* Mutatus mother clouds: Stratocumulus, stratus.

* USA Today Weather site on stratus clouds

Onshore winds in spring and early summer bring mists or low stratus clouds ( known locally as sea frets ) to the coast and moors.

* Adiabatic compression heating in the trough of each wave oscillation may also evaporate cumulus or stratus clouds in the airmass, creating a " wave window " or " Foehn gap ".

A typical June Gloom day consists of marine stratus clouds covering the coast of southern California, extending a varying distance inland depending on the strength of the June Gloom effect each day.

However, scientists believe that the presence of actinoform clouds within the marine stratus is indicative of an increase in drizzle and the onset of precipitation.