Meteorology questions

A long, typically low, horizontal, detached, tube-shaped cloud mass, often appearing to roll slowly about a horizontal axis. The roll cloud, volutus, is a soliton, not attached to other clouds and is an example of an undular bore.

Lenticular clouds are stationary clouds that form in the troposphere, typically in perpendicular alignment to the wind direction. They are often comparable in appearance to a lens or saucer. Because of their unique appearance, they have been brought forward as an explanation for some unidentified flying object (UFO) sightings.

Humidity is the measure of the amount of moisture in the air. A psychrometer is an example of a hygrometer. A psychrometer uses two thermometers to measure relative humidity; one measures the dry-bulb temperature and the other measures the wet-bulb temperature.

A weather front is a boundary separating two masses of air of different densities, and is the principal cause of meteorological phenomena outside the tropics. The air masses separated by a front usually differ in temperature and humidity.

Noctilucent clouds, or night shining clouds, are tenuous cloud-like phenomena in the upper atmosphere of Earth. They are first known to have been observed in 1885, two years after the eruption of Krakatoa volcano. Noctilucent clouds require water vapour, dust and exhaust. The dust is believed to come from micrometeors, although particulates from volcanoes and dust from the troposphere are also possibilities. The exhaust are from Space Shuttles.

The Madden–Julian oscillation is a large-scale coupling between atmospheric circulation and tropical deep convection. Unlike a standing pattern like the El Niño Southern Oscillation, the Madden–Julian oscillation is a traveling pattern that propagates eastward, through the atmosphere above the warm parts of the Indian and Pacific oceans. This overall circulation pattern manifests itself most clearly as anomalous rainfall.

Catatumbo lightning is an atmospheric phenomenon in Venezuela. It occurs only over the mouth of the Catatumbo River where it empties into Lake Maracaibo. The phenomenon is characterized by almost continuous lightning and occurs during 260 nights a year, 10 hours per day and up to 280 times per hour. It has been known for centuries as the Lighthouse of Maracaibo, since it is visible for miles around Lake Maracaibo

The Morning Glory cloud is a roll cloud, or arcus cloud, that can be up to 1,000 km long, 1 to 2 km high and often only 100 to 200 metres above the ground. The southern part of the Gulf of Carpentaria in Northern 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.

Vostok Station is a Russian research station in inland Princess Elizabeth Land, Antarctica. Founded by the Soviet Union in 1957, the station lies at the southern Pole of Cold, with the lowest reliably measured natural temperature on Earth of −89.2°C (−128.6°F; 184.0 K)

Chinook is claimed to mean "ice-eater", as it can make snow one foot deep vanish in one day. The snow partly melts and partly evaporates in the dry wind. The greatest recorded temperature change in 24 hours was caused by Chinook winds on 15 January 1972, in Loma, Montana; the temperature rose from −48 to +9 °C (−54 to +49 °F)