A monsoon is traditionally a seasonal reversing wind accompanied by corresponding changes in precipitation but is now used to describe seasonal changes in atmospheric circulation and precipitation associated with annual latitudinal oscillation of the Intertropical Convergence Zone (ITCZ) between its limits to the north and south of the equator. Usually, the term monsoon is used to refer to the rainy phase of a seasonally changing pattern, although technically there is also a dry phase. The term is also sometimes used to describe locally heavy but short-term rains.
Orographic lift occurs when an air mass is forced from a low elevation to a higher elevation as it moves over rising terrain. As the air mass gains altitude it quickly cools down adiabatically, which can raise the relative humidity to 100% and create clouds and, under the right conditions, precipitation.
In meteorology, a low-pressure area, low area or low is a region where the atmospheric pressure is lower than that of surrounding locations. It is the opposite of a high-pressure area. Low-pressure areas are commonly associated with inclement weather, while high-pressure areas are associated with lighter winds and clear skies. Winds circle anti-clockwise around lows in the northern hemisphere, and clockwise in the southern hemisphere, due to opposing Coriolis forces. Low-pressure systems form under areas of wind divergence that occur in the upper levels of the atmosphere (aloft). The formation process of a low-pressure area is known as cyclogenesis. In meteorology, atmospheric divergence aloft occurs in two kinds of places:
The climate of India consists of a wide range of weather conditions across a vast geographic scale and varied topography. Based on the Köppen system, India encompasses a diverse array of climatic subtypes. These range from arid and semi-arid regions in the west to highland, sub-arctic, tundra, and ice cap climates in the northern Himalayan regions, varying with elevation. The northern lowlands experience subtropical conditions, with some areas at higher altitudes, like Srinagar, touching continental climates. In contrast, much of the south and the east exhibit tropical climate conditions, which support lush rainforests in these territories. Many regions have starkly different microclimates, making it one of the most climatically diverse countries in the world. The country's meteorological department follows the international standard of four seasons with some local adjustments: winter ,spring(February to March),summer, South West monsoon and North-east monsoon or autumn.
The 1986 Pacific typhoon season was an above average season, featuring 29 named storms, 19 typhoons, and 3 super typhoons. It has no official bounds; it ran year-round in 1986, but most tropical cyclones tend to form in the northwestern Pacific Ocean between May and December. These dates conventionally delimit the period of each year when most tropical cyclones form in the northwestern Pacific Ocean. Tropical Storms formed in the entire west pacific basin were assigned a name by the Joint Typhoon Warning Center. Tropical depressions that enter or form in the Philippine area of responsibility are assigned a name by the Philippine Atmospheric, Geophysical and Astronomical Services Administration or PAGASA. This can often result in the same storm having two names.
The 1985 Pacific typhoon season was a slightly above average season in terms of named storms, though most storms were weak and short-lived. The season had 28 named storms, 15 typhoons and 1 super typhoon. It ran year-round, thus ending the two-season run which began in 1983 that only had tropical cyclones forming between June and December. These dates conventionally delimit the period of each year when most tropical cyclones form in the northwestern Pacific Ocean. A total of 57 tropical depressions formed this year, of which only 28 became tropical storms and were assigned a name by the Joint Typhoon Warning Center. This made the season well above average. Additionally, tropical depressions that enter or form in the Philippine area of responsibility were assigned a name by the Philippine Atmospheric, Geophysical and Astronomical Services Administration or PAGASA. This can often result in the same storm having two names. This year, a total of 17 storms were named this way.
The 1981 Pacific typhoon season was a slightly above average season that produced 29 tropical storms, 13 typhoons and two intense typhoons. The season ran throughout 1981, though most tropical cyclones typically develop between May and October. The season's first named storm, Freda, developed on March 12 while the final storm, Lee, dissipated on December 29. Tropical cyclones only accounted for 12 percent of the rainfall in Hong Kong this season, the lowest percentage for the protectorate since 1972.
The characteristics of United States rainfall climatology differ significantly across the United States and those under United States sovereignty. Summer and early fall bring brief, but frequent thundershowers and tropical cyclones which create a wet summer and drier winter in the eastern Gulf and lower East Coast. During the winter, and spring, Pacific storm systems bring Hawaii and the western United States most of their precipitation. Low pressure systems moving up the East Coast and through the Great Lakes, bring cold season precipitation to from the Midwest to New England, as well as Great Salt Lake. The snow to liquid ratio across the contiguous United States averages 13:1, meaning 13 inches (330 mm) of snow melts down to 1 inch (25 mm) of water.
Delhi features a monsoon influenced humid subtropical climate bordering a hot semi-arid climate, with high variation between summer and winter temperatures and precipitation. Delhi's version of a humid subtropical climate is markedly different from many other humid subtropical cities such as São Paulo, Houston, and Brisbane in that the city features dust storms and wildfire haze due to its semi-arid climate.
The North American monsoon, variously known as the Southwest monsoon, the Mexican monsoon, the New Mexican monsoon, or the Arizona monsoon is a term for a pattern of pronounced increase in thunderstorms and rainfall over large areas of the southwestern United States and northwestern Mexico.
Pakistan's climate varies from a continental type of climate in the north (Gilgit-Baltistan,Kashmir,KPK), a mountainous dry climate in the west (Baluchistan), a wet climate in the East (Punjab) an arid climate in the Thar Desert, to a tropical climate in the southeast (Sindh), characterized by extreme variations in temperature, both seasonally and daily, because it is located on a great landmass barely north of the Tropic of Cancer.
The 1993 North Indian Ocean cyclone season was the least active on record in the basin, with only four tropical disturbances. There are two main seas in the North Indian Ocean – the Bay of Bengal to the east of the Indian subcontinent and the Arabian Sea to the west. The India Meteorological Department (IMD) issued advisories for the systems in its official capacity as the local Regional Specialized Meteorological Center, while the Joint Typhoon Warning Center also issued advisories for two of the storms on an unofficial basis. Of the five disturbances tracked by the IMD, two intensified into cyclonic storms.
Rain is a atmospheric phenomenon of water droplets that have condensed from atmospheric water vapor and then fall under gravity. Rain is a major component of the water cycle and is responsible for depositing most of the fresh water on the Earth. It provides water for hydroelectric power plants, crop irrigation, and suitable conditions for many types of ecosystems.
Inflow is the flow of a fluid into a large collection of that fluid. Within meteorology, inflow normally refers to the influx of warmth and moisture from air within the Earth's atmosphere into storm systems. Extratropical cyclones are fed by inflow focused along their cold front and warm fronts. Tropical cyclones require a large inflow of warmth and moisture from warm oceans in order to develop significantly, mainly within the lowest 1 kilometre (0.62 mi) of the atmosphere. Once the flow of warm and moist air is cut off from thunderstorms and their associated tornadoes, normally by the thunderstorm's own rain-cooled outflow boundary, the storms begin to dissipate. Rear inflow jets behind squall lines act to erode the broad rain shield behind the squall line, and accelerate its forward motion.
Earth rainfall climatology Is the study of rainfall, a sub-field of meteorology. Formally, a wider study includes water falling as ice crystals, i.e. hail, sleet, snow. The aim of rainfall climatology is to measure, understand and predict rain distribution across different regions of planet Earth, a factor of air pressure, humidity, topography, cloud type and raindrop size, via direct measurement and remote sensing data acquisition. Current technologies accurately predict rainfall 3–4 days in advance using numerical weather prediction. Geostationary orbiting satellites gather IR and visual wavelength data to measure realtime localised rainfall by estimating cloud albedo, water content, and the corresponding probability of rain.
A Gulf of California moisture surge, or simply gulf surge, is a meteorological event where a pulse of high humidity air is pushed up the Gulf of California. Gulf surges bring moisture to southern Arizona during the North American Monsoon. Prior to the 1970s, the consensus of meteorologists was the moisture that fueled the central and southern Arizona monsoon resulted from the movement of the Bermuda High to a more south and west position, which in turn transported water vapor to the region from the Gulf of Mexico. However, operational meteorologists in the 1970s described episodic surges of moisture that infiltrated the area that was thought to originate in the Gulf of California. It was noted that these episodes were likely to be associated with a convective system near the tip of the Baja peninsula such as a tropical cyclone or an easterly wave.
The climate of Asia is dry across its southwestern region. Some of the largest daily temperature ranges on Earth occur in the western part of Asia. The monsoon circulation dominates across the southern and eastern regions, due to the Himalayas forcing the formation of a thermal low which draws in moisture during the summer. The southwestern region of the continent experiences low relief as a result of the subtropical high pressure belt; they are hot in summer, warm to cool in winter, and may snow at higher altitudes. Siberia is one of the coldest places in the Northern Hemisphere, and can act as a source of arctic air mass for North America. The most active place on Earth for tropical cyclone activity lies northeast of the Philippines and south of Japan, and the phase of the El Nino-Southern Oscillation modulates where in Asia landfall is more likely to occur. Many parts of Asia are being impacted by climate change.
The Monsoon of South Asia is among several geographically distributed global monsoons. It affects the Indian subcontinent, where it is one of the oldest and most anticipated weather phenomena and an economically important pattern every year from June through September, but it is only partly understood and notoriously difficult to predict. Several theories have been proposed to explain the origin, process, strength, variability, distribution, and general vagaries of the monsoon, but understanding and predictability are still evolving.
The 2015 North Indian Ocean cyclone season was an event in the annual cycle of tropical cyclone formation. It was an average season with 4 cyclonic storms. The North Indian Ocean cyclone season has no official bounds, but cyclones tend to form between months of April and December, with the peak from May to November. These dates conventionally delimit the period of each year when most tropical cyclones form in the northern Indian Ocean.
