The envelope of gases that surround a planet. The earth's atmosphere is mainly nitrogen and oxygen.

The force exerted by the weight of the atmosphere, also known as barometric pressure. The internationally recognized unit for measuring atmospheric pressure is the kilopascal.

A severe weather condition characterized by low temperatures, strong winds, and reduced visibility from falling or blowing snow.

Snow lifted from the earth's surface by the wind to a height of 2 meters or more. Blowing snow rises higher than difting snow.

The prevalent or characteristic meteorological conditions, and their extremes, of any place or region.

A transition zone where a cold air mass advances and replaces a warm air mass.

As the surface of the earth cools at night, warm moist air near the ground is chilled and water vapour in the air condenses into droplets on the grass and other objects. The surface on which the dew forms has been cooled by radiation during the night, to a temperature below the dew point of the surrounding air, but is still above freezing. If the temperature of the surface falls below freezing, then frost will form instead. Dew is particularly heavy on clear nights when the earth's surface cools rapidly. When a blanket of cloud insulates the earth, the cooling rate is slower.

The temperature to which air must be cooled for saturation to occur.

Snow raised from the earth's surface by the wind to a height of less than 2 metres. Drifting snow is not as high as blowing snow.

Small water droplets between 0.2 and 0.5 millimetres in diameter that fall slowly and reduce visibility more than light rain.

A cloud with its base at the earth's surface.

Supercooled rain that falls in liquid form and then freezes upon striking a cold object or ground.

Freezing spray occurs when a combination of low temperatures and strong winds cause sea spray to freeze on a ship's superstructure or on other structures either in the sea or near the water's edge. A weather warning is issued whenever moderate or heavy ship icing is expected.

A covering of ice produced by deposition on exposed surfaces when the air temperature falls below the frost point (see dew).

A satellite that orbits the earth at the same rate that the earth rotates and thus remains over a fixed place above the equator.

A warm, swift, narrow ocean current flowing parallel to the east coast of North America. The current then turns and flows south of Nova Scotia and Newfoundland and continues on towards Europe.

Precipitation of small balls or larger pieces of ice (hailstones) with a diameter ranging from 5 to 50 mm or sometimes more, and which fall either separately or fused into irregular lumps.

An area of high pressure around which the wind blows clockwise in the Northern Hemisphere and counterclockwise in the Southern Hemisphere. Also called a High.

A general term that refers to the air's water vapour content. (See Relative humidity).

Cyclones of tropical origin with wind speeds of at least 118 kilometres per hour. A hurricane is a large, rotating storm, where the winds blow counterclockwise around a relatively calm centre called the 'eye.' Visit the Canadian Hurricane Centre for more information.

A line connecting points of equal pressure on a map.

Relatively strong winds concentrated within a narrow band in the upper atmosphere.

A unit of speed equal to 1 nautical mile per hour. 1 knot = 1.853 kilometres per hour.

A cold, strong ocean current flowing parallel to the east coast of Labrador.

An area of low pressure around which the winds blow counterclockwise in the Northern Hemisphere and clockwise in the Southern Hemisphere. Also called a Low.

A unit for expressing the atmospheric pressure. Average global sea level pressure is about 1013 millibars (101.3 kilopascals).

The climatological average high temperature for a given day.

The climatological average low temperature for a given day.

A complex frontal system that forms when a cold front overtakes a warm front, cutting the low pressure system off from its warm air.

A satellite whose orbit closely parallels the earth's meridian lines and thus crosses the polar regions on each orbit.

(atmospheric pressure) The pressure exerted by the weight of air above a given point, sometimes expressed in millibars (mb) or inches of mercury (Hg). The internationally recognized unit for measuring atmospheric pressure is the kilopascal.

The probability that measurable precipitation (at least 0.2 millimetres) will occur during the forecast period. It is often used as a measure of the meteorologist's confidence that the event will / will not occur.

An electronic instrument used to detect objects (such as water droplets) by their ability to reflect and scatter microwaves back to a receiver.

Precipitation in the form of liquid water drops that have diameters greater than that of drizzle.

The ratio of the amount of water vapour required for saturation (at a particular temperature and pressure). The ratio of the air's actual vapour pressure to its saturation vapour pressure.

An elongated area of relatively high pressure extending from the centre of a high pressure region; the opposite of a trough.

Showery precipitation falls from convective cumulus-type clouds and can be further identified by one of more of the following features:

1. Showers often (but not always) begin and end abruptly.
2. Showers usually occur in periods of short duration, perhaps 15 minutes or so, but they may last much longer.
3. There are usually rapid fluctuations in the intensity of the precipitation.
4. There is usually a noticeable brightening of the sky between showers.

The difference in sea level from that predicted in tidal tables, due to the forces of the atmosphere. The two main atmospheric components that contribute to storm surge are atmospheric pressure and wind. Storm surges can be either positive or negative.

Les Suête is an Acadian phrase, local to the west coastal highlands area of Cape Breton Island, and used to describe the very strong Southeast winds common to that area.

A cumulonimbus cloud producing lightning and thunder. May also produce heavy rain, hail, and strong gusty winds.

An elongated area of relatively low pressure extending from the centre of a low pressure region; opposite of a ridge.

Whisps or streaks of precipitation falling out of a cloud which evaporates before reaching the ground.

A transition zone where a cold air mass retreats and is replaced by a warm air mass.

The condition of the troposphere (lower atmosphere) at any particular time and place.

MSC - Atlantic issues special weather warnings whenever expected weather conditions are such that the public welfare is endangered. They come under various headings, such as: storm or hurricane warnings, freezing rain warnings, and heavy snowfall warnings. See Warning Criteria and Terminology for a list of the warning criteria.

Annoucements used to warn the public of a possible occurence of hazardous phenomenona. Weather watches are used only in the case of severe weather related to thunderstorms.

The change of wind speed and/or wind direction over a given distance.

The cooling effect of any combination of temperature and wind, expressed as a loss of body heat.

Wreckhouse is located between Cape Ray and St Andrew's in Southwestern Newfoundland. This area is, at times, subject to extremely violent southeast winds, which have been strong enough to blow railcars off their tracks.