Updrafts/Downdrafts rising and sinking air The atmosphere can be unstable for updrafts but stable for downdrafts, stable for updrafts but unstable for downdrafts, stable for both, or unstable for both.
Updrafts and downdrafts are some of the main causes of in-flight turbulence in planes, and are one reason airlines try to avoid regions of bad weather. Extreme cases, known as downbursts and microbursts are responsible for many airplane crashes.
Downdraft - A column of generally cool air that rapidly sinks to the ground, most often accompanied by precipitation in a shower or thunderstorm.
downdraft convective available potential energy"(Abbreviated DCAPE.) The maximum energy available to a descending parcel, according to parcel theory.
Downdraft - a relatively small-scale current of air with marked downward motion
Downstream - in the same direction as a stream or other flow, or toward the direction in which the flow is moving ...
Downdraft - A small-scale column of air that rapidly sinks toward the ground, usually accompanied by precipitation as in a shower or thunderstorm. A downburst is the result of a strong downdraft.
DOWNDRAFT A sudden descent of cool or cold air to the ground, usually with precipitation, and associated with a thunderstorm or shower. Related term: updraft
DOWNPOUR A heavy rain. Related term: cloudburst ...
Downdraft Downward moving air, usually within a thunderstorm cell.
Drainage basin A fixed geographical region from which a river and its tributaries drain water.
downdraft—A relative small scale downward current of air; often observed on the lee side of large objects restricting the smooth flow of the air or in precipitation areas in or near cumuliform clouds.
DOWNDRAFT - Sinking air in the atmosphere. Commonly associated with precipitation regions of thunderstorms.
DOWNGRADE - A demotion in status of a storm system, usually a tropical system. Example, the hurricane was DOWNGRADED to a tropical storm.
Rear Flank Downdraft (or RFD) - A region of dry air subsiding on the back side of, and wrapping around, a mesocyclone. It often is visible as a clear slot wrapping around the wall cloud.
The violent downdraft having shared the circulation with the updraft now strangles it.
Precipitation weakens and the thunderstorm, a short lived creature, weakens and dies.
A convective downdraft with an affected outflow area of at least 2?Ǭ? miles wide and peak winds lasting between 5 and 20 minutes. Intense macrobursts may cause tornado-force damage of up to F3 intensity.
Macroscale ...
Forward flank downdraft
The main region of downdraft in the forward, or leading, part of a supercell, where most of the heavy precipitation is. Compare with rear flank downdraft. See pseudo-warm front and supercell.
Fractus ...
A strong localized downdraft less than 4 km wide that occurs beneath severe thunderstorms. A strong downdraft greater than 4 km across is called a downburst.
Microclimate(6)
The climate structure of the air space near the surface of the earth.
Downburst: a strong downdraft current of air from a cumulonimbus cloud, often associated with intense thunderstorms.
Drizzle: precipitation consisting of numerous minute droplets of water less than 0.5 mm (500 micrometers) in diameter.
The structure typically is most pronounced on the leading edge of the updraft, while drier air from the rear flank downdraft often erodes the clouds on the trailing side of the updraft.BarometerAn instrument for measuring atmospheric pressure.
Triple point also may refer to a point on the gust front of a supercell, where the warm moist inflow, the rain-cooled outflow from the forward flank downdraft, and the rear flank downdraft all intersect; ...
MicroburstA convective downdraft with an affected outflow area of less than 2½ miles wide and peak winds lasting less than 5 minutes.
Lee WaveThe wavelike effect, characterized by severe updrafts and downdrafts, that occurs in the lee of a mountain range when rapidly flowing air is lifted up the steep front of a mountain range. Compare mountain wave.
Occluded MesocycloneA mesocyclone in which air from the rear-flank downdraft has completely enveloped the circulation at low levels, cutting off the inflow of warm unstable low-level air.
FIRST GUST Another name for the initial wind surge observed at the surface as the result of downdrafts forming the leading edge or gust front of a thunderstorm.
The first type is known as a single cell storm usually composed of a convective cloud containing one updraft and one downdraft segment.
A strong downdraft in a column of precipitation marks its dissipating stages.
They are characterized by a single updraft core and a single downdraft that descends into the same area as the updraft. The downdraft and its outflow boundary then cut off the thunderstorm inflow.
Cell Convection in the form of a single updraft, downdraft, or updraft/downdraft couplet, typically seen as a vertical dome or tower as in a cumulus or towering cumulus cloud.
Downbursts: Surface winds in excess of 62 km/hr (39 mph) caused by a small-scale downdraft from the base of a convective cloud.
In meteorology, the term is used specifically to describe vertical transport of heat and moisture in the atmosphere, especially by updrafts and downdrafts in an unstable atmosphere.
DOWNBURST - A strong downdraft of air which induces an outburst of damaging winds on or near the ground.
DRIFTING SNOW - An uneven distribution of snowfall/snow depth caused by strong surface winds, but does not reduce surface visibility.
Gust Front- the leading edge of a thunderstorm's downdraft air that is most prominent beneath the rain-free base and the leading edge of a thunderstorm; ...
PLOW/PLOUGH WIND The spreading downdraft and strong straight-line winds preceding a thunderstorm. So named in the American Midwest because of its ability to flatten tall grasses as it passes. Related term: first gust ...
DOWNBURST: A severe localized downdraft from a thunderstorm.
DRIZZLE: Small, slowly falling water droplets, with diameters between .2 and .5 millimeters.
ECMF: European Centre for Meteorology Forecast model.
MICROBURST: A strong localized downdraft from a thunderstorm with peak gusts lasting 2 to 5 minutes.
MILLIBAR: A unit of atmospheric pressure. 1 mb = 100 Pa (pascal). Normal surface pressure is approximately 1013 millibars.
strong downdrafts produce strong winds associated with thunderstorms
midlevel clouds
altostratus (midlevel flat, layerd cloud)
a corona closely circles the sun or moon shining through altostratus
altocumulus (midlevel puffy clouds) ...
DOWNBURST: A strong localized downdraft of wind that is experienced beneath a severe thunderstorm.
DRIFTING SNOW: The uneven distribution of snowfall. Snow depth caused by strong surface winds.
Macroburst A downburst (strong downdraft) that affects a path longer than 4.0 km (2.5 mi).
Magnetosphere Regions of the upper atmosphere encompassed by the Earth's magnetic field; deflected by solar wind into a teardrop-shaped cavity.
Microburst - A small downdraft of air with an outflow diameter of less than 2.5 miles with the peak winds lasting from 2 to 5 minutes. This can effect a plane's performance.
Entrainment - The infiltration of surrounding air into a vertically nonmoving air column. For example, the influx of cool, dry air into the downdraft of a cumulonimbus cloud; a process that acts to intensify the downdraft.
A mesoscale area of high pressure, typically associated with cooler air from the rainy downdraft area of a thunderstorm or a complex of thunderstorms. A gust front or outflow boundary separates a bubble high from the surrounding air.
A small high that may be created by precipitation and vertical instability associated with thunderstorm activity. A product of downdrafts, it is relatively cold and often has the characteristics of a different air mass.
Supercell storm An enormous severe thunderstorm whose updrafts and downdrafts are nearly in balance, allowing it to maintain itself for several hours. It can produce large hail and tornadoes.
Gust Front - The leading edge of gusty surface winds from thunderstorm downdrafts; sometimes associated with a shelf cloud or roll cloud.
microburstAn intense, localized downdraft of air that spreads on the ground, causing rapid changes in wind direction and speed; a localized downburst.
Downdraft A relatively small-scale, downward moving current of air. Downward total radiation Solar and terrestrial radiation directed downwards (towards the earth's surface); incoming radiation.
 See also: Storm, Air, Cloud, Thunder, Thunderstorm
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