Low pressure systems
A low pressure system (cyclone) develops where relatively warm air ascends from the Earth's surface. These are systems of closed isobars surrounding a region of relatively low pressure.
LOW PRESSURE SYSTEM An area of a relative pressure minimum that has converging winds and rotates in the same direction as the earth. This is counterclockwise in the Northern Hemisphere and clockwise in the Southern Hemisphere.
low pressure system: area of minimum air pressure, and cyclonic air movement.
low (low pressure system): area with lower atmospheric pressure than its surrounding areas; this makes air from surrounding areas to flow into the low, the end result of which is probably cloudiness and precipitation.
(return to top)M ...
BOMB- A low pressure system that decreases in central pressure by at least 24 millibars in a 24 hour period.
Low pressure systems that originate in the panhandle region of Texas and Oklahoma which initially move east and then "hook" or recurve more northeast toward the upper Midwest or Great Lakes region.
Low Pressure System - A whirling mass of warm, moist air that generally brings stormy weather with strong winds. When viewed from above, winds spiral into a low-pressure center in a counterclockwise rotation in the Northern Hemisphere.
A low pressure system that develops over subtropical waters that initially has a non-tropical circulation, but in which some elements of tropical cyclone cloud structure are present. Subtropical cyclones can evolve into tropical cyclones.
Surface low pressure systems will tend to be smaller in area and have stronger surface winds than a given high pressure system, due to the addition of surface friction to the pressure gradient force and coriolis effect that drive the circulation.
A strong low pressure system that affects the Mid Atlantic and New England States. It can form over land or over the coastal waters.
A shallow low pressure system caused by the strong heating of the earth's surface. These lows are usually weak and are strongest in the late afternoon. They can trigger afternoon or evening showers and thunderstorms.
Heat wave ...
A low pressure system that has its coldest temperatures at or near the center of circulation, and is thermally barotropic with respect to a horizontal plane. Also known as a cold core low.
Cold Low- a low pressure system with cold air mass from near the surface to all vertical levels (also called a cold core low).
Texas Hooker Low pressure systems that originate in the panhandle region of Texas and Oklahoma. The lows initially move east and then "hook" or recurve more northeast toward the upper Midwest or Great Lakes region.
WAVE CYCLONE - A low pressure system with waves and / or fronts associated with it. Wave cyclones are almost always extratropical type storms associated with frontal systems or upper level disturbances.
Noreaster: A deep low pressure system which moves along the Eastern United States seaboard producing heavy strong winds causing heavy land erosion and much damage along the shore.
CLOSED LOW A low pressure system that is completely encircled by an isobar. They often move slowly, as they displaced south of the main westerlies.
A general increase in the central pressure of a low pressure system.Fire WindA thermally driven wind blowing radially inward toward a fire, ...
Texas HookerSame as Panhandle Hook - low pressure systems that originate in the panhandle region of Texas and Oklahoma which initially move east and then "hook" or recurve more northeast toward the upper Midwest or Great Lakes region.
Snow AdvisoryThis product is issued by the National Weather Service when a low pressure system produces snow that may cause significant inconveniences, ...
Lake Effect Snow AdvisoryThis product is issued by the National Weather Service when pure lake effect snow (this is where the snow is a direct result of lake effect snow and not because of a low pressure system) may pose a hazard or it is life ...
DeepeningA decrease in the central pressure of a surface low pressure system. The storm is intensifying.Deformation ZoneThe change in shape of a fluid mass by variations in wind, specifically by stretching and/or shearing.
Cyclogenesis and Cyclolosis "Cyclogenesis" and "cyclolosis" are terms used by meteorologists to refer to stages of an extratropical cyclone or low pressure system.
NAO Index - This index measures the anomalies in sea level pressure between the Icelandic low pressure system and the Azores high pressure system.
Snow Advisory- This product is issued when a low pressure system produces snow that may cause significant inconveniences but do not meet warning criteria and if caution is not exercised could lead to life threatening situations.
Subtropical cyclone: A low pressure system that develops in subtropical waters (north of 20 north degrees latitude) and initially has non-tropical features (see table below for a list of tropical features) but does have some element of a tropical ...
Surface data indicates that a small scale low pressure system, about 100 miles in diameter, probably accounted for the LEWP configuration. Supercells often form near or immediately northeast of such a low.
Used in describing the history of a low pressure system or an area of cyclonic circulation, it means an increase in the central pressure of the system.
Alberta clipper"A low pressure system that is often fast-moving, has low moisture content, and originates in western Canada (in or near Alberta province).
A shift in position of various high and low pressure systems that in climate terms is usually defined as an index (i.e.
The main difference, however, between a lake effect snow and a "standard" snow storm is that lake effect snow storms are not low pressure system storms.
NOR' EASTER: An intense low pressure system that tracks along the east coast of the United States, producing strong northeast winds, large waves, and intense precipitation.
Cut-Off Low - An upper level low pressure system that is no longer in the normal west to east upper air flow. Usually a cut-off low will lie to the South of the established upper air flow.
Tropical Cyclone - the general term for a large low pressure system that originates over the tropical oceans; includes tropical depressions, tropical storms, and hurricanes ...
Tropical Storm - An organized low pressure system in the tropics with wind speeds between 38 and 74 mph.
Tropical Storm Warning- A warning issued when sustained winds of 39 to 73 mph (34 to 63 knots) are expected within 24 hours.
Subtropical Cyclone: A non-frontal low pressure system that has characteristics of both tropical and extratropical cyclones.
Storm Track: The path followed by the centre of a low pressure system or cyclone over a given period of time, usually its lifetime.
Dry Slot - A zone of dry (and relatively cloud-free) air which wraps east- or northeastward into the southern and eastern parts of a synoptic scale or mesoscale low pressure system. A dry slot generally is seen best on satellite photographs.
JET STREAM: Strong winds concentrated within a narrow band in the atmosphere. The jet stream often "steers" surface features such as front and low pressure systems.
KATABATIC WIND: Local winds a result of cold, dense air flowing downhill.
synoptic scale - Used with respect to weather systems ranging in size from several hundred kilometers to several thousand kilometers, the scale of migratory high and low pressure systems (frontal cyclones) of the lower troposphere.
air at high altitudes above the earth that generally flows from west to east over the mid-latitudes. The jet stream separates cold polar air from warmer air to the south and generally "steers" surface features such as fronts and low pressure systems.
Warm fronts usually form on the eastern sides of low pressure systems, create wide areas of clouds and rain, and move at an average speed of 15 mph.
 See also: Low pressure, Pressure, Weather, Low, Air
|
