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35-571: The Morning Glory cloud is a rare meteorological phenomenon consisting of a low-level atmospheric solitary wave and associated cloud, occasionally observed in different locations around the world. The wave often occurs as an amplitude -ordered series of waves forming bands of roll clouds . The southern part of the Gulf of Carpentaria in Northern Australia is the only known location where it can be predicted and observed regularly due to

70-468: A soliton or an undular bore , which is a wave that has a single crest and moves without changing speed or shape. They have been called "the biggest waves on the planet". The wave may occur without the appearance of any clouds. Unusual cloud formations have been noticed here since ancient times. The local Garrwa Aboriginal people called it kangólgi . Royal Australian Air Force pilots first reported this phenomenon in 1942. The Morning Glory cloud of

105-1343: A Morning Glory cloud formed over Ruskin, FL , US. List of meteorological phenomena Also actiniform . Also adiabatic warming . Also barometric pressure . Sometimes called aerology . Also simply called an area forecast . Also baroclinicity . Also barotropicity . Also clear ice . Also blocking high and blocking anticyclone . Also standing cloud . Also castellatus . Also pilot balloon or pibal . Also climate science . Also irisation . Also cloud genus . Also saddle point and neutral point . Also cold spell and cold snap . Also vortex Crow instability . Also red adaptation goggles . Also daybreak . Also dewpoint or dew-point . Also non-adiabatic process . Also simply diffuse radiation . Also diurnal range . Also drouth . Also heat storm . Also duster or duststorm . Also atmometer . Also fetch length . Also fire devil and fire tornado . Also pyrocumulus and fire cloud . Also beaver's tail . Also white rainbow , mist bow , and cloud bow . Also foehn wind . Also front-flank downdraft . Often used interchangeably with scud . Also simply called

140-462: A brownish haze that can cause respiratory problems. The Great Smog of 1952 in London , England, is one of the most serious examples of such an inversion. It was blamed for an estimated 10,000 to 12,000 deaths. Sometimes the inversion layer is at a high enough altitude that cumulus clouds can condense but can only spread out under the inversion layer. This decreases the amount of sunlight reaching

175-581: A difference in sea breezes that develop over the Peninsula and the Gulf. On the large scale, Morning Glories are usually associated with frontal systems crossing central Australia and high pressure in northern Australia. Locals have noted that the Morning Glory is likely to occur when the humidity in the area is high, which provides moisture for the cloud to form, and when strong sea breezes have blown

210-539: Is a phenomenon in which a layer of warmer air overlies cooler air. Normally, air temperature gradually decreases as altitude increases, but this relationship is reversed in an inversion. An inversion traps air pollution , such as smog , near the ground. An inversion can also suppress convection by acting as a "cap". If this cap is broken for any of several reasons, convection of any humidity can then erupt into violent thunderstorms . Temperature inversion can cause freezing rain in cold climates . Usually, within

245-457: Is at lower pressure, and lower pressure results in a lower temperature, following the ideal gas law and adiabatic lapse rate . Under the right conditions, the normal vertical temperature gradient is inverted so that the air is colder near the surface of the Earth. This can occur when, for example, a warmer, less-dense air mass moves over a cooler, denser air mass. This type of inversion occurs in

280-510: Is broken, either by extreme convection overcoming the cap or by the lifting effect of a front or a mountain range, the sudden release of bottled-up convective energy—like the bursting of a balloon—can result in severe thunderstorms. Such capping inversions typically precede the development of tornadoes in the Midwestern United States . In this instance, the "cooler" layer is quite warm but is still denser and usually cooler than

315-491: Is instead refracted down towards the earth by the temperature-inversion boundary layer. This phenomenon is called tropospheric ducting . Along coastlines during Autumn and Spring, due to multiple stations being simultaneously present because of reduced propagation losses, many FM radio stations are plagued by severe signal degradation disrupting reception. In higher frequencies such as microwaves , such refraction causes multipath propagation and fading . When an inversion layer

350-413: Is only one cloud, sometimes there are up to ten consecutive roll clouds. Three distinct types of Morning Glory clouds have been identified. The Morning Glory is often accompanied by sudden wind squalls, intense low-level wind shear , a rapid increase in the vertical displacement of air parcels, and a sharp pressure jump at the surface. Cloud is continuously formed at the leading edge while being eroded at

385-431: Is present, if a sound or explosion occurs at ground level, the sound wave is refracted by the temperature gradient (which affects sound speed) and returns to the ground. The sound, therefore, travels much better than normal. This is noticeable in areas around airports, where the sound of aircraft taking off and landing often can be heard at greater distances around dawn than at other times of day, and inversion thunder which

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420-459: Is refracted most, with the blue component of sunlight "completely scattered out by Rayleigh scattering ", making green the first or last light from the upper rim of the solar disc to be seen. Very high frequency radio waves can be refracted by inversions, making it possible to hear FM radio or watch VHF low -band television broadcasts from long distances on foggy nights. The signal, which would normally be refracted up and away into space,

455-510: The English Channel , Munich , Berlin , eastern Russia , and other maritime regions of Australia. There was one distinct and well formed roll cloud observed spanning from horizon to horizon (east to west), just prior to midnight on 22 October 2015 at 50.3044°N, 96.9692°W (about 35 km North of Winnipeg , Manitoba , Canada ), followed up by a series of them (but much less distinctive) shortly after midnight on 24 October 2015. There

490-561: The F scale . Also glazed frost . Also soft hail and snow pellets . Also gust front tornado . Also tropical cell . Also Lower Atmosphere Severity Index . Also apparent temperature , felt air temperature , and humiture . Also velocity diagram . Also huayco . Also the doldrums or the calms . Also simply jet . Also jet stream core or jet maximum . Also George's index . Inversion (meteorology) In meteorology , an inversion (or temperature inversion )

525-695: The Gulf of California off the Mexican coast. The phenomenon has also been observed from Sable Island , 180 km southeast of Nova Scotia . A Morning Glory also passed through Yarmouth, Nova Scotia , in April 2009, as well as several communities in Newfoundland in May 2022. In contrast to the Gulf of Carpentaria where the Morning Glory is visible in the morning, those in the Maritimes have all occurred during

560-508: The fridges frost over and the café tables' corners curl upwards at the Burketown Pub, there is enough moisture in the air for the clouds to form. Reportedly, all winds cease at ground level as the cloud passes over. Although the Morning Glory clouds over the southern part of the Gulf of Carpentaria are the most frequent and predictable, similar phenomena have occasionally been observed elsewhere, e.g. , over central United States , in

595-442: The Gulf of Carpentaria has been studied by multiple teams of scientists since the early 1970s. The first studies were published by Reg H. Clarke ( University of Melbourne ). Multiple studies have followed since then, proposing diverse mathematical models explaining the complex movements of air masses in the region. One of the main contributors for the formation of the morning glory clouds is the mesoscale circulations associated with

630-410: The breeze from the gulf blows in from the west. The two breezes meet in the middle of the peninsula, forcing the air to rise there and form a line of clouds over the spine of the peninsula. When night comes, the air cools and descends and at the same time a surface inversion (where air temperature increases with height) forms over the gulf. The densities in this stable layer are different above and below

665-509: The configuration of land and sea in the area. Morning Glory clouds can be observed from Burketown from late September to early November. The town attracts glider pilots intent on riding this phenomenon. There are generally only a handful of well formed spectacular clouds during this period at Burketown. During the 2012 season there were only four to be seen from there, but quite a few ragged unspectacular cloud lines were seen. Often they start to break up before arriving at Burketown or pass to

700-418: The effects of temperature inversions because they both produce more atmospheric pollutants and have higher thermal masses than rural areas, resulting in more frequent inversions with higher concentrations of pollutants. The effects are even more pronounced when a city is surrounded by hills or mountains since they form an additional barrier to air circulation. During a severe inversion, trapped air pollutants form

735-786: The evening. Rare examples have been observed via satellite observation over the Joseph Bonaparte Gulf in the Eastern Kimberley region of Australia as well as over the Arabian Sea . A Morning Glory cloud was observed in 2007 over the Campos dos Goytacazes bay in the state of Rio de Janeiro, Brazil. In August 2011, it happened again over Peregrino Field in South Campos Basin in Brazil. The phenomenon

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770-425: The front produces a cloud, which forms the leading edge of the cylinder, and evaporates in the back, hence forming the Morning Glory cloud. The cloud lasts until the surface inversion disappears with the heating of the day. There are other ways in which Morning Glory clouds form, especially in rarer cases in other parts of the world, but these are far less understood. Local weather lore in the area suggests that when

805-401: The ground and prevents new thermals from forming. As the clouds disperse, sunny weather replaces cloudiness in a cycle that can occur more than once a day. As the temperature of air increases, the index of refraction of air decreases, a side effect of hotter air being less dense. Normally this results in distant objects being shortened vertically, an effect that is easy to see at sunset when

840-471: The inversion layer to higher altitudes, and eventually even pierce it, producing thunderstorms, and under the right circumstances, tropical cyclones . The accumulated smog and dust under the inversion quickly taints the sky reddish, easily seen on sunny days. Temperature inversions stop atmospheric convection (which is normally present) from happening in the affected area and can lead to high concentrations of atmospheric pollutants. Cities especially suffer from

875-406: The inversion. The air descending from the peninsula to the east goes underneath the inversion layer and this generates a series of waves or rolling cylinders which travel across the gulf. These cylinders of air roll along the underside of the inversion layer, so that the air rises at the front of the wave and sinks at the rear. In the early morning, the air is saturated enough so that the rising air in

910-464: The lower atmosphere (the troposphere ) the air near the surface of the Earth is warmer than the air above it, largely because the atmosphere is heated from below as solar radiation warms the Earth's surface, which in turn then warms the layer of the atmosphere directly above it, e.g., by thermals ( convective heat transfer ). Air temperature also decreases with an increase in altitude because higher air

945-430: The lower part of the inversion layer capping it. An inversion can develop aloft as a result of air gradually sinking over a wide area and being warmed by adiabatic compression, usually associated with subtropical high-pressure areas . A stable marine layer may then develop over the ocean as a result. As this layer moves over progressively warmer waters, however, turbulence within the marine layer can gradually lift

980-438: The north and only stay well formed over water. In an aircraft there is a significantly better chance of sighting the cloud. A Morning Glory cloud is a roll cloud , or arcus cloud , that can be up to 1,000 kilometres (620 mi) long,1 to 2 kilometres (0.62 to 1.24 mi) high, often only 100 to 200 metres (330 to 660 ft) above the ground. The cloud often travels at the rate of 10 to 20 metres per second. Sometimes there

1015-461: The preceding day. The following is a summary of the conditions that cause the Morning Glory cloud to form in the Gulf of Carpentaria (after hypothesis of R.H.Clarke, as described in 1981). First, Cape York , which is the peninsula that lies to the east of the gulf, is large enough that sea breezes develop on both sides. During the day, the breeze from the Coral Sea coast blows in from the east and

1050-448: The sun is visible as an oval. In an inversion, the normal pattern is reversed, and distant objects are instead stretched out or appear to be above the horizon, leading to the phenomenon known as a Fata Morgana or mirage . Inversions can magnify the so-called " green flash "—a phenomenon occurring at sunrise or sunset, usually visible for a few seconds, in which the sun's green light is isolated due to dispersion. The shorter wavelength

1085-407: The trailing edge. Showers or thunderstorms may develop in its wake. In the front of the cloud, there is strong vertical motion that transports air up through the cloud and creates the rolling appearance, while the air in the middle and rear of the cloud becomes turbulent and sinks. The cloud quickly dissipates over land where the air is drier. The cloud can also be described as a solitary wave or

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1120-525: The vicinity of warm fronts , and also in areas of oceanic upwelling such as along the California coast in the United States. With sufficient humidity in the cooler layer, fog is typically present below the inversion cap. An inversion is also produced whenever radiation from the surface of the earth exceeds the amount of radiation received from the sun, which commonly occurs at night, or during

1155-402: The winter when the sun is very low in the sky. This effect is virtually confined to land regions as the ocean retains heat far longer. In the polar regions during winter, inversions are nearly always present over land. A warmer air mass moving over a cooler one can "shut off" any convection which may be present in the cooler air mass: this is known as a capping inversion . However, if this cap

1190-478: Was also recorded on Batroun's shore (Lebanon – Middle East) in September 2004. On 20 November 2013, a Morning Glory formation formed over the greater Durban area. On 4 June 2015 a Morning Glory cloud formed over St. Cloud, FL , US. On 3 November 2016 a Morning Glory cloud formed over Appelscha , The Netherlands. On 5 February 2018 a Morning Glory cloud formed over Richmond, Virginia , US. On 30 August 2018,

1225-517: Was another rare roll cloud formation that was observed in Masury, Ohio, 41.211168°N, -80.537849°W, on 27 May 2012, at 2:30 pm EST. This rare cloud event was observed by a mother and daughter, who also reported that high winds accompanied this formation, immediately after it being observed. Considering the rarity of the event in this region, it is seen as a once in a lifetime occurrence. Morning Glory clouds have occasionally been reported on Cape Cod and in

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