See also: Surface, Air, Weather, Pressure, Cloud
rotational instability"In general, any instability of a rotating fluid system; usually synonymous with inertial instability.
rotational"Possessing vorticity. See also irrotational.
The spinning of a body, such as the earth, about its axis.
Rotation Process of the Earth turning on its axis. Rotationm determines day and night, and the length of the day. Compare with revolution.
- S - ...
Rotation in the opposite sense from Earth's rotation, i.e. clockwise in the Northern Hemisphere as seen from above. The opposite of cyclonic rotation.
Weather Glossary Search Page
Weather Glossary Source List ...
A rotation-type anemometer consists of an array of three (or four) hemispherical cups mounted symmetrically about a vertical rotation axis.
La rotation de la terre fait dévier les mouvements de l'air et de l'eau partout sauf à l'Équateur, phénomène connu sous le nom d'effet de Coriolis.
If rotation is observed, then the term dust whirl or debris cloud should be used.
*Dust Whirl - A rotating column of air rendered visible by dust. Similar to debris cloud; see also dust devil, gustnado, tornado.
The rotation of a tropical storm is more recognizable than for a tropical depression. Tropical storms can cause a lot of problems even without becoming a hurricane. However, most of the problems a tropical storm cause stem from heavy rainfall.
the rotation of the earth which causes winds to be deflected to the right in the northern hemisphere and to the left in the southern hemisphere.
TORQUE - Rotational force applied to the propeller.
TORQUE EFFECT - The tendency for an aircraft to roll the opposite way the propeller is rotating due to drag on the propeller.
A area of rotation of storm size that may often be found on the southwest part of a supercell. Its circulation can be larger than the tornado that may develop within it, but not necessarily.
The Earth's rotation imparts an acceleration known as the Coriolis effect, Coriolis acceleration, or colloquially, Coriolis force. This acceleration causes cyclonic systems to turn towards the poles in the absence of strong steering currents.
(or cyclonic rotation) Circulation (or rotation) which is in the same sense as the Earth's rotation, i.e., clockwise (in the Southern Hemisphere) as seen from above. Winds around synoptic-scale low pressure systems circulate cyclonically.
**The Earth's Rotation & Speed**
1. The earth rotates on it's axis.
2. The earth takes 24 hours to complete 1 rotation which is: ...
ANTI-CYCLONIC ROTATION Rotation opposite that of the earth. For example, clockwise in the Northern Hemisphere as would be seen from a view above. The opposite of cyclonic rotation.
Cyclonic - Rotation in the same sense that the earth rotates, counter-clockwise in the Northern Hemisphere. Wind around a low; subgeostrophic.
Anticyclonic Rotation Rotation in the opposite sense as the Earth's rotation. In the Northern Hemisphere, this would be clockwise as would be seen from above.
Antlophobia The fear of floods.
VORTICITY- Any rotation within a horizontal or vertical windflow.
VORT MAX, VORT LOBE- Highest value of vorticity. A region of maximum vorticity. A wind flow through a vort max will produce divergence downwind from the vort max.
3) Analyze areas of rotation (when generated from one AZRAN to another).
A sidereal day is equivalent to one complete rotation of the earth relative to the equinox, which is 23 hours, 56 minutes, and 4.091 seconds.
Rankine VortexVelocity profile for a symmetric circulation in which the inner core is in solid rotation and tangential winds outside the core vary inversely with radial distance from the center.
It is used to aid in displaying shear and rotation in storms and storm top divergence that might otherwise be obscured by the storm's motion, investigate the 3-D velocity structure of a storm, ...
GeosynchronousTerm applied to any equatorial satellite with an orbital velocity equal to the rotational velocity of the earth.
Fujiwhara effectThe Fujiwhara effect describes the rotation of two storms around each other.Funnel cloudA rotating, cone-shaped column of air extending downward from the base of a thunderstorm but not touching the ground.
Rotation anemometer A type of anemometer in which the rotation of an element serves to measure the wind.
AnticycloneA large-scale circulation of winds around a central region of high atmospheric pressure, clockwise in the Northern Hemisphere, counterclockwise in the Southern HemisphereAnticyclonic RotationRotation in the opposite sense as the ...
Is any rotation observed in the cloud elements etc? What was the wind regime, before, during and after the event? Note particularly the onset of notable gustiness, changes of wind in direction/speed as compared with onset of precipitation etc.
The serious tornado is aided by rotation aloft, especially at the edges of large mesoscale rotating convective storms. Again, centrifugal force aids the formation of a core of low pressure that hurries air upwards.
Since the earth is rotating, the force observed as gravity is the resultant of the force of gravitation and the centrifugal force arising from this rotation. It is directed normal to sea level and to its geopotential surfaces.
(One radian = 57.2958°, 2p radians = 360°) or, the rate of angular rotation around a cyclone or anticyclone = w. (A rotor that spins at 1000 rpm has twice the angular velocity of one spinning at 500 rpm).
An effect of the earth's rotation that deflects the direction of any large moving object (including the wind) to the right in the Northern Hemisphere, and to the left in the Southern Hemisphere.
The deflection (to the right in the northern hemisphere) is caused by the rotation of the earth.Corrective Action Report (CAR)Used to identify and document problems with ARM systems, physical infrastructure, or instruments.
TORNADO - A region of rotation extending from the base of a thunderstorm or other convective cloud to the earth's surface. This is a vortex, or wind velocity field, with a speed of at least 40 MPH at the surface.
This daily rotation of the earth means that in 24 hours a point on its equator moves a distance of some 40 000 kilometres, giving it a tangential velocity of about 1670 kilometres per hour (or roughly 1000 mph).
Cup anemometer is used to measure the wind speed from the speed of rotation of a windmill which consist of 3 or 4 hemispherical or conical cups, each fixed to the ends of horizontal arms attached to a vertical axis.
Straight Line Winds - Any wind that is not associated with rotation. The term is mainly used to distinguish thunderstorm winds from tornadic winds.
*Mesocyclone - A storm-scale region of rotation, typically around 2-6 miles in diameter and often found in the right rear flank of a supercell (or often on the eastern, or front, flank of an HP storm).
VORTICITY The measurement of the rotation of a small air parcel. It has vorticity when the parcel spins as it moves along its path.
When seen from within several miles, many wall clouds exhibit rapid upward motion and cyclonic rotation. However, not all wall clouds rotate.
*Cyclonic Circulation (or Cyclonic Rotation) - Circulation (or rotation) which is in the same sense as the Earth's rotation, i.e., counterclockwise (in the Northern Hemisphere) as would be seen from above.
Precipitation often totally envelops the region of rotation, making visual identification of any embedded tornadoes difficult and very dangerous.
A measure of the local rotation in a fluid flow. In weather analysis and forecasting, ...
Vorticity - A measure of the local rotation in a fluid flow. In weather analysis and forecasting, ...
Coriolis Force- An apparent force caused by the rotation of the Earth. In the Northern Hemisphere winds are deflected to the right, and in the Southern Hemisphere to the left.
Cloud rotation is one example of differential motion, but not all differential motion indicates rotation. For example, horizontal wind shear along a gust front may result in differential cloud motion without the presence of rotation.
A force per unit mass that arises solely from the earth's rotation, acting as a deflecting force. It is dependent on the latitude and the speed of the moving object.
Vorticity This is a term used by meteorologists to describe the rotation of a fluid. An example is the rotation of the atmosphere (a gaseous fluid) around relatively large scale low and high pressure cells.
This helps forecasters to identify the tell-tale circular rotation typical of budding funnel clouds. Further, this radar can detect areas of high winds in the atmosphere not observable from the ground. It can also sense areas of wind-shear.
Coriolis effect A deflective force arising from the rotation of the earth on its axis; affects principally synoptic-scale and global-scale winds.
Vorticity - A measure of the rotation of air in a horizontal plane. Positive (counter-clockwise or cyclonic) vorticity can be correlated with surface low development and upward vertical motion (in areas of positive vorticity advection).
absolute vorticity—the rotation of the Earth imparts vorticity to the atmosphere; absolute vorticity is the combined vorticity due to this rotation and vorticity due to circulation relative to the Earth (relative vorticity).
They also occasionally contain rotation on a broad scale. Because of its structure, the severe storm may last for hours beyond the lifetime of a normal thunderstorm while producing large hail, high winds, torrential rain, and possible tornadoes.
Coriolis Force - A force that deflects moving objects to one side because of the Earth's rotation. The object is still going straight but the Earth moves underneath it, making it look like it is moving to one side.
Coriolis Effect - The deflective effect of Earth's rotation on all free-moving objects, including the atmosphere and oceans. Deflection is to the right in the Northern Hemisphere and to the left in the Southern Hemisphere.
HORIZONTAL VORTICITY- A rotation of air caused by vertical speed or directional wind shear.
HORSE LATITUDES - subtropical regions where anticyclones produce settled weather.
Anticyclonic- describes the movement of air around a high pressure; and rotation about the local vertical oppostie the earth's rotation.
Coriolis Effect- The curving motion of anything, such as air, caused by the rotation of the Earth.
Cyclone- A low-pressure system in which winds spin inward in a counterclockwise direction in the northern hemisphere.
VORTICITY: A measure of the amount of "spin" (or rotation) in the atmosphere.
WAA: Warm Air Advection
WARM FRONT: A boundary between a warm airmass that is replacing a cooler airmass.
Cyclonic: Air flow around the centre of a surface Low. In the Northern Hemisphere, this flow is counter-clockwise as seen from above. (In the Southern Hemisphere, it is clockwise.) Also, any rotation in the direction of the Earth's rotation.
CUP ANEMOMETER: Anemometer which measures wind speed by the speed of rotation of 3 or 4 hemispherical or conical cups, each fixed to the end of a horizontal arm projecting from a vertical axis.
See also: Surface, Air, Weather, Pressure, Cloud