MORNING GLORY CLOUD
The Morning Glory cloud is a rare meteorological phenomenon occasionally observed in different locations around the world. The southern part of the Gulf of Carpentaria in Northen Australia is the only known location where it can be predicted and observed on a more or less regular basis due to the configuration of land and sea in the area. The settlement of Burketown attracts glider pilotsintent on riding this phenomenon.
About Morning Glory Cloud
Morning Glory clouds can be observed from Burketown from late September to early November. 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 that can be up to 1,000 kilometres long, 1 to 2 kilometres high, often only 100 to 200 metres above the ground and can move at speeds up to 60 kilometres per hour. Sometimes there is only one cloud, sometimes there are up to eight consecutive roll clouds.
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. 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 can also be described as a solitary wave or a soliton or an undular bore, which is a wave that has a single crest and moves without changing speed or shape.
Why Did It Happen?
The Morning Glory cloud is not clearly understood because their rarity means they have little significance in terms of rainfall or climate.
Regardless of the complexity behind the nature of this atmospheric phenomenon, some conclusions have been made about its causes. Through research, one of the main causes of most Morning Glory occurrences is the mesoscale circulations associated with 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 the preceding day.
Other Morning Glory Cloud
Morning Glory clouds have occasionally been reported in :
- The Sea of Cortez of the Mexican coast.
- Sable Islan, 180 km southeast of Nova Scotia.
- Yarmouth, Nova Scotia.
- The Campos dos Goytacazes bay in the state of Rio de Jeneiro, Brazil.
- Batroun's shore (Lebanon — Middle East).
Although the cloud phenomenon is common every year in the Gulf of Carpentaria, scientists still do not know exactly how this beautiful clouds may form.
