200px|thumb|A Morning Glory cloud formation between [[Burketown and Normanton, Australia.]]

200px|thumb|right|The location of the Gulf of Carpentaria.

200px|thumb|right|Satellite photo of morning cloud formations over the Gulf of Carpentaria. Northern part of the visible linear cloud is North Australian Squall Line, Morning Glory cloud is the very southern part of this linear cloud.

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 the configuration of land and sea in the area.

Description

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 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 long, high, often only above the ground. The cloud often travels at the rate of 10 to 20 metres per second. Sometimes there is only one cloud, sometimes there are up to ten consecutive roll clouds. Three distinct types of Morning Glory clouds have been identified. Cloud is continuously formed at the leading edge while being eroded at the trailing edge. The wave may occur without the appearance of any clouds. Royal Australian Air Force pilots first reported this phenomenon in 1942.

The Morning Glory cloud of 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).

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).

Other reported occurrences

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 the English Channel, Munich, The phenomenon 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, a Morning Glory cloud formed over Ruskin, FL, US.

See also

  • Gravity wave
  • Hector (cloud)

Notes

  • Smith, Deborah. (2002) Morning Glory lures scientists to ride cloud nine The Sydney Morning Herald. 16 September 2002
  • Meteorology of the Morning Glory Cloud
  • Morning Glory Cloud of the Gulf of Carpentaria Galleries and articles covering the history of soaring the wave.