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Funnel Cloud
A funnel cloud is a funnel-shaped cloud of condensed water droplets, associated with a rotating column of wind and extending from the base of a cloud (usually a cumulonimbus or towering cumulus cloud) but not reaching the ground or a water surface. A funnel cloud is usually visible as a cone-shaped or needle like protuberance from the main cloud base. Funnel clouds form most frequently in association with supercell thunderstorms, and are often, but not always, a visual precursor to tornadoes. Funnel clouds are visual phenomena, but these are not the vortex of wind itself. "Classic" funnel clouds If a funnel cloud touches the surface, the feature is considered a tornado, although ground level circulations begin before the visible condensation cloud appears. Most tornadoes begin as funnel clouds, but some funnel clouds do not make surface contact and these cannot be counted as tornadoes from the perspective of a naked eye observer, even as tornadic circulations of some intensit ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tornado Skips And Hops Across The Central Minnesota
A tornado is a violently rotating column of air that is in contact with the surface of Earth and a cumulonimbus cloud or, in rare cases, the base of a cumulus cloud. It is often referred to as a twister, whirlwind or cyclone, although the word cyclone is used in meteorology to name a weather system with a low-pressure area in the center around which, from an observer looking down toward the surface of the Earth, winds blow counterclockwise in the Northern Hemisphere and clockwise in the Southern Hemisphere. Tornadoes come in many shapes and sizes, and they are often (but not always) visible in the form of a condensation funnel originating from the base of a cumulonimbus cloud, with a cloud of rotating debris and dust beneath it. Most tornadoes have wind speeds less than , are about across, and travel several kilometers (a few miles) before dissipating. The most extreme tornadoes can attain wind speeds of more than , can be more than in diameter, and can stay on the grou ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Air Pressure
Atmospheric pressure, also known as air pressure or barometric pressure (after the barometer), is the pressure within the atmosphere of Earth. The Standard atmosphere (unit), standard atmosphere (symbol: atm) is a unit of pressure defined as , which is equivalent to 1,013.25 Bar (unit), millibars, 760millimetre of mercury, mm Hg, 29.9212inch of mercury, inchesHg, or 14.696pounds per square inch, psi.International Civil Aviation Organization. ''Manual of the International Standard Atmosphere, ICAO Standard Atmosphere'', Doc 7488-CD, Third Edition, 1993. . The atm unit is roughly equivalent to the mean sea-level atmospheric pressure on Earth; that is, the Earth's atmospheric pressure at sea level is approximately 1 atm. In most circumstances, atmospheric pressure is closely approximated by the fluid pressure, hydrostatic pressure caused by the weight of Earth's atmosphere, air above the measurement point. As elevation increases, there is less overlying atmospheric mass, so atmospher ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Synoptic Scale Meteorology
In meteorology, the synoptic scale (also called the large scale or cyclonic scale) is a horizontal length scale of the order of or more. This corresponds to a horizontal scale typical of mid-latitude depressions (e.g. extratropical cyclones). Most high- and low-pressure areas seen on weather maps (such as surface weather analyses) are synoptic-scale systems, driven by the location of Rossby waves in their respective hemisphere. Low-pressure areas and their related frontal zones occur on the leading edge of a trough within the Rossby wave pattern, while high-pressure areas form on the back edge of the trough. Most precipitation areas occur near frontal zones. The word '' synoptic'' is derived from the Ancient Greek word (), meaning "seen together". The Navier–Stokes equations applied to atmospheric motion can be simplified by scale analysis in the synoptic scale. It can be shown that the main terms in horizontal equations are Coriolis force and pressure gradient terms ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Outflow Boundary
An outflow boundary, also known as a gust front, is a storm-scale or mesoscale meteorology, mesoscale boundary separating thunderstorm-cooled air (Outflow (meteorology), outflow) from the surrounding air; similar in effect to a cold front, with passage marked by a wind shift and usually a drop in temperature and a related pressure jump. Outflow boundaries can persist for 24 hours or more after the thunderstorms that generated them dissipate, and can travel hundreds of kilometers from their area of origin. New thunderstorms often develop along outflow boundaries, especially near the point of intersection with another boundary (cold front, dry line, another outflow boundary, etc.). Outflow boundaries can be seen either as fine lines on weather radar imagery or else as arcs of low clouds on weather satellite imagery. From the ground, outflow boundaries can be co-located with the appearance of roll clouds and shelf clouds. Outflow boundaries create low-level wind shear which can be ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sea Breeze
A sea breeze or onshore breeze is a wind that blows in the afternoon from a large body of water toward or onto a landmass. By contrast, a land breeze or offshore breeze is a wind that blows in the night from a landmass toward or onto a large body of water. Sea breezes and land breezes are both important factors in coastal regions' prevailing winds. Sea breeze and land breeze develop due to differences in air pressure created by the differing heat capacity, heat capacities of water and dry land. As such, sea breezes and land breezes are more localised than prevailing winds. Since land heats up much faster than water under solar radiation, a sea breeze is a common occurrence along coasts after sunrise. On the other hand, dry land also cools faster than water without solar radiation, so the wind instead flows from the land towards the sea when the sea breeze dissipates after sunset. The land breeze at nighttime is usually shallower than the sea breeze in daytime. Unlike the day ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Low Pressure System
In meteorology, a low-pressure area (LPA), 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 (such as cloudy, windy, with possible rain or storms), 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 first is in the area on the east side of upper troughs, which form half of a Rossby wave within the Westerlies (a trough with large wavelength that extends through the troposphere). * A secon ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cold Front
A cold front is the leading edge of a cooler mass of air at ground level that replaces a warmer mass of air and lies within a pronounced surface Trough (meteorology), trough of Low-pressure area, low pressure. It often forms behind an extratropical cyclone (to the west in the Northern Hemisphere, to the east in the Southern Hemisphere, Southern), at the leading edge of its cold air Advection#Meteorology, advection pattern—known as the cyclone's dry "conveyor belt" flow. Temperature differences across the boundary can exceed from one side to the other. When enough moisture is present, rain can occur along the boundary. If there is significant Convective instability, instability along the boundary, a Squall line, narrow line of thunderstorms can form along the frontal zone. If instability is weak, a broad shield of rain can move in behind the Weather front, front, and evaporative cooling of the rain can increase the temperature difference across the front. Cold fronts are stronger ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Funnel Cloud3 - NOAA
A funnel is a tube or pipe that is wide at the top and narrow at the bottom, used for guiding liquid or powder into a small opening. Funnels are usually made of stainless steel, aluminium, glass, or plastic. The material used in its construction should be sturdy enough to withstand the weight of the substance being transferred, and it should not react with the substance. For this reason, stainless steel or glass are useful in transferring diesel fuel, while plastic funnels are useful in the kitchen. Sometimes disposable paper funnels are used in cases where it would be difficult to adequately clean the funnel afterwards (for example, in adding motor oil into a car). Dropper funnels, also called dropping funnels or tap funnels, have a tap to allow the controlled release of a liquid. A flat funnel, made of polypropylene, utilises living hinges and flexible walls to fold flat. The term "funnel" may refer to the chimney or smokestack on a steam locomotive and commonly refers to ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Waterspout
A waterspout is a rotating column of air that occurs over a body of water, usually appearing as a funnel-shaped cloud in contact with the water and a cumuliform cloud. There are two types of waterspout, each formed by distinct mechanisms. The most common type is a weak vortex known as a "fair weather" or "non-tornadic" waterspout. The other less common type is simply a classic tornado occurring over water rather than land, known as a "tornadic", "supercellular", or "mesocyclonic" waterspout, and accurately a "tornado over water". A fair weather waterspout has a five-part life cycle: formation of a dark spot on the water surface; spiral pattern on the water surface; formation of a spray ring; development of a visible condensation funnel; and ultimately, decay. Most waterspouts do not suck up water. While waterspouts form mostly in tropical and subtropical areas, they are also reported in Europe, Western Asia (the Middle East), Australia, New Zealand, the Great Lakes, Antarc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Wall Cloud
A wall cloud (murus or pedestal cloud) is a large, localized, persistent, and often abrupt lowering of cloud that develops beneath the surrounding base of a cumulonimbus cloud and from which tornadoes sometimes form. It is typically beneath the rain-free base (RFB) portion of a thunderstorm, and indicates the area of the strongest updraft within a storm. Rotating wall clouds are an indication of a mesocyclone in a thunderstorm; most strong tornadoes form from these. Many wall clouds do rotate; however, some do not. Genesis Wall clouds are formed by a process known as Entrainment (meteorology), entrainment, when an inflow (meteorology), inflow of warm, moist air rises and Convergence zone, converges, overpowering wet, rain-cooled air from the normally downwind downdraft. As the warm air continues to entrain the cooler air, the air temperature drops, and the dew point increases (thus the dew point depression decreases). As this air continues to rise, it becomes more Vapor pressu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tornadogenesis
Tornadogenesis is the process by which a tornado forms. There are many types of tornadoes, varying in methods of formation. Despite ongoing scientific study and high-profile research projects such as VORTEX projects, VORTEX, tornadogenesis is a volatile process and the intricacies of many of the mechanisms of tornado formation are still poorly understood. A tornado is a violently rotating column of air in contact with the surface and a cumuliform cloud base. Tornado formation is caused by the stretching and aggregating/merging of environmental and/or storm-induced vorticity that tightens into an intense vortex. There are various ways this may come about and thus various forms and sub-forms of tornadoes. Although each tornado is unique, most kinds of tornadoes go through a life cycle of formation, maturation, and dissipation. The process by which a tornado dissipates or decays, occasionally conjured as tornadolysis, is of particular interest for study as is tornadogenesis, longev ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
