A very early Good Morning - Today is:
Current: 11.4°C, Max: 12.1°C, Min: 11.4°C
The current forecast is: Rain showers early with some sunshine later in the day. High 17C. Winds WNW at 10 to 15 km/h. Chance of rain 40%. *
Last weather station contact: Wednesday, 27 September 2017 at 01:38:46. Updated in seconds
Station Forecast: Fairly fine, improving | Sunrise: 06:59 | Sunset: 19:19 | Dawn: 06:32 | Dusk: 19:46
Weather Forecast
Temperature : Current trend is Falling, changing by -0.1 °C/hr  11.4°C   Humidity : Current humidity is Very Damp 98%
Based upon today's weather there is a Low Fire Danger (restrictions may apply)
Fire Danger
Pressure : Current trend is Rising slowly, changing by 0.30 hPa/hr  1007.59hPa   Rainfall : Current trend is Steady 0.0mm
Wind Speed :  N  Current wind speed is Calm (F0) from N (0°) 0.0km/h   Wind Gust : Current trend is Steady 0.0km/h
Sun Light : 0Lux, 0.0hrs   Solar UV :  0.0UVI  0W/m2
It feels like 11.7°C. Three clothing layers recommended.There will be 2min 41s more daylight tomorrow.

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Weather Terminology Dictionary and Site References
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A
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ABSOLUTE HUMIDITY

A type of humidity that considers the mass of water vapor present per unit volume of space. Also considered as the density of the water vapor. It is usually expressed in grams per cubic meter.

ABSOLUTE TEMPERATURE SCALE

A temperature scale with a freezing point of +273°K (Kelvin) and a boiling point of +373°K.

ABSOLUTE ZERO

Considered to be the point at which theoretically no molecular activity exists or the temperature at which the volume of a perfect gas vanishes. The value is 0° Kelvin, -273.15° Celsius and -459.67° Fahrenheit.

ADVECTION FOG

Fog that develops when warm moist air moves over a colder surface, cooling that air to below its dew point.

AIR

This is considered the mixture of gases that make up the earth's atmosphere. The principal gases that compose dry air are Nitrogen (N2) at 78.09%, Oxygen (O2) at 20.946%, Argon (A) at 0.93%, and Carbon Dioxide (CO2) at 0.033%. One of the most important constituents of air and most important gases in meteorology is water vapor (H2O).

AIR MASS

An extensive body of air throughout which the horizontal temperature and moisture characteristics are similar.

AIR MASS THUNDERSTORM

A thunderstorm that is produced by convection within an unstable air mass through an instability mechanism. Such thunderstorms normally occur within a tropical or warm, moist air mass during the summer afternoon as the result of afternoon heating and dissipate soon after sunset. Such thunderstorms are not generally associated with fronts and are less likely to become severe than other types of thunderstorms. However, that does not preclude them from having brief heavy downpours.

AIR POLLUTION

The soiling of the atmosphere by contaminants to the point that may cause injury to health, property, plant, or animal life, or prevent the use and enjoyment of the outdoors.

AIR QUALITY STANDARDS

The maximum level which will be permitted for a given pollutant. Primary standards are to be sufficiently stringent to protect the public health. Secondary standards must protect the public welfare, including property and aesthetics.

Arctic air.

ALTIMETER

An instrument used to determine the altitude of an object with respect to a fixed level. The type normally used by meteorologists measures the altitude with respect to sea level pressure.

ALTITUDE

In meteorology, the measure of a height of an airborne object in respect to a constant pressure surface or above mean sea level.

ALTOSTRATUS

This middle cloud genus is composed of water droplets, and sometimes ice crystals, In the mid-latitudes, cloud bases are generally found between 15,000 and 20,000 feet. White to gray in colour, it can create a fibrous veil or sheet, sometimes obscuring the sun or moon. It is a good indicator of precipitation, as it often precedes a storm system. Virga often falls from these clouds.

ANEMOMETER

An instrument that measures the speed or force of the wind.

ATMOSPHERE

The gaseous or air portion of the physical environment that encircles a planet. In the case of the earth, it is held more or less near the surface by the earth's gravitational attraction. The divisions of the atmosphere include the troposphere, the stratosphere, the mesosphere, the ionosphere, and the exosphere.

ATMOSPHERIC PRESSURE

The pressure exerted by the atmosphere at a given point. Its measurement can be expressed in several ways. One is in millibars. Another is in inches or millimeters of mercury (Hg).

AUTUMN

The season of the year which occurs as the sun approaches the winter solstice, and characterized by decreasing temperatures in the mid-latitudes. Customarily, this refers to the months of September, October, and November in the North Hemisphere and the months of March, April, and May in the Southern Hemisphere. Astronomically, this is the period between the autumnal equinox and the winter solstice.

 

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BALL LIGHTNING

A relatively rare form of lightning consisting of a luminous ball, often reddish in colour, which moves rapidly along solid objects or remains floating in mid-air.

BAROGRAPH

An instrument that continuously records a barometer's reading of atmospheric pressure.

BAROMETER

An instrument used to measure atmospheric pressure. Two examples are the aneroid barometer and the mercurial barometer.

BAROMETRIC PRESSURE

The pressure exerted by the atmosphere at a given point. Its measurement can be expressed in several ways. One is in millibars. Another is in inches or millimeters of mercury (Hg).

BEAUFORT WIND SCALE

A system of estimating and reporting wind speeds. It is based on the Beaufort Force or Number, which is composed of the wind speed, a descriptive term, and the visible effects upon land objects and/or sea surfaces. The scale was devised by Sir Francis Beaufort (1777-1857), hydrographer to the British Royal Navy.

BLACK ICE

Thin, new ice on fresh or salt water that appears dark in colour because of its transparency. Also refers to thin, transparent ice on road surfaces.

BLIZZARD

A severe weather condition characterized by low temperatures, winds 35 mph or greater, and sufficient falling and/or blowing snow in the air to frequently reduce visibility to 1/4 mile or less for a duration of at least 3 hours. A severe blizzard is characterized by temperatures near or below 10°F, winds exceeding 45 mph, and visibility reduced by snow to near zero.

BLOCKING HIGH

The development of a warm ridge or cutoff high aloft at high latitudes which becomes associated with a cold high at the surface, causing a split in the westerly winds. Such a high will move very slowly, tending to move westward during intensification and eastward during dissipation. It prevents the movement of migratory cyclones across its latitudes.

BLOWING DUST

Dust that is raised by the wind to heights of six feet or greater. It is reported as "BLDU" in an observation and on the METAR.

BLOWING SAND

Sand that is raised by the wind to heights of six feet or greater. It is reported as "BLSA" in an observation and on the METAR.

BLOWING SNOW

Snow that is raised by the wind to heights of six feet or greater. It is reported as "BLSN" in an observation and on the METAR.

BLOWING SPRAY

Salt spray that is raised by the wind to heights of six feet or greater. It is reported as "BLPY" in an observation and on the METAR.

BOILING POINT

The temperature at which a liquid changes to a vaporous state. The temperature at which the equilibrium vapor pressure between a liquid and its vapor is equal to the external pressure on the liquid. The boiling point of pure water at standard pressure is 100°C or 212°F.

BROKEN

The amount of sky cover for a cloud layer between 5/8ths and 7/8ths, based on the summation layer amount for that layer.

 

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CALM

Atmospheric conditions devoid of wind or any other air motion. In oceanic terms, it is the apparent absence of motion of the water surface when there is no wind or swell.

CARBON DIOXIDE (CO2)

A heavy, colourless gas that is the fourth most abundant constituent of dry air, comprising 0.033% of the total.

CELSIUS TEMPERATURE SCALE

The standard scale used to measure temperature in most areas outside the United States. On this scale, the freezing point of water is 0°C and the boiling point is 100°C. To convert a Fahrenheit temperature to Celsius, subtract 32 from it and then multiply by 5/9:
°C = (°F - 32) * 5/9

CENTRAL PRESSURE

The atmospheric pressure at the center of a high or low. It is the highest pressure in a high and the lowest pressure in a low, referring to the sea level pressure of the system on a surface chart.

CLEAR

The state of the sky when no clouds or obscurations are observed or detected from the point of observation.

CLEAR AIR TURBULENCE

Name given to turbulence that may occur in perfectly clear air without any visual in warning in the form of clouds. It is often found in the vicinity of the jet stream where large shears in the horizontal and vertical are found, although this turbulence is not limited just to jet stream locale. Other areas where it may occur include near mountains, in closed lows aloft, and in regions of wind shear. May be referred to as CAT.

CLEAR ICE

A glossy, clear, or translucent ice formed by the relatively slow freezing of large supercooled in water droplets. The droplets spread out over an object, such as an aircraft wing's leading edge, prior to complete freezing and forms a sheet of clear ice.

CLIMATE

The historical record and description of average daily and in seasonal weather events that help describe a region. Statistics are generally drawn over several decades. The word is derived from the Greek klima, meaning inclination, and reflects the importance early scholars attributed to the sun's influence.

CLOUD

A visible collection of minute particle matter, such as water droplets and/or ice crystals, in the free air. A cloud forms in the atmosphere as a result of condensation of water vapor. Condensation nuclei, such as in smoke or dust particles, form a surface upon which water vapor can condense.

CLOUD BANK

A well-defined cloud mass that can be observed at a distance. It covers the horizon, but is not directly overhead.

CLOUDBURST

A sudden, heavy rainfall of a showery nature.

COLD

A condition marked by low or decidedly subnormal temperature. The lack of heat.

COLD FRONT

The leading edge of an advancing cold air mass that is under running and displacing the warmer air in its path. Generally, with the passage of a cold front, the temperature and humidity decrease, the pressure rises, and the wind shifts (usually from the southwest to the northwest in the Northern Hemisphere). Precipitation is generally at and/or behind the front, and with a fast-moving system, a squall line may develop ahead of the front.

COMMA CLOUD

A feature seen on satellite images with a distinctive comma-shape. This is indicative of a synoptic cloud pattern associated with large, well-developed low pressure systems.

CONVERGENCE

Wind movement that results in a horizontal net inflow of air into a particular region. Convergent winds at lower levels are associated with upward motion. Contrast with divergence.

CUMULIFORM

Clouds composed of water droplets that exhibit vertical development. The density of the droplets often blocks sunlight, casting shadows on the earth's surface. With increasing vertical height, they are often associated with convection. Bases of these clouds are generally no more than 3,000 feet above the ground, but they can develop past the troposphere in both temperate and tropical latitudes. They are classified as low clouds and include all varieties of cumulus and cumulonimbus. The opposite in type are the horizontal development of stratiform clouds.

CUMULONIMBUS

A vertically developed cumulus cloud, often capped by an anvil-shaped cirriform cloud. Also called a thunderstorm cloud, it is frequently accompanied by heavy showers, lightning, thunder, and sometimes hail, tornadoes or strong, gusty winds.

CUMULUS

One of the three basic cloud forms (the others are cirrus and stratus). It is also one of the two low cloud types. A cloud that develops in a vertical direction from the base (bottom) up. They have flat bases and dome- or cauliflower-shaped upper surfaces. The base of the cloud is often no more than 3,000 feet above the ground, but the top often varies in height. Small, separate cumulus are associated with fair weather (cumulus humilis). With additional heating from the earth's surface, they can grow vertically throughout the day. The top of such a cloud can easily reach 20,000 or more into the troposphere. Under certain atmospheric conditions, these clouds can develop into larger clouds, known as towering cumulus (cumulus congestus), and may produce a rain shower. Further development may create a cumulonimbus.

CYCLONE

An area of closed pressure circulation with rotating and converging winds, the center of which is a relative pressure minimum. The circulation is counterclockwise in the Northern Hemisphere and clockwise in the Southern Hemisphere. Also called a low pressure system and the term used for a tropical cyclone in the Indian Ocean. Other phenomena with cyclonic flow may be referred to by this term, such as dust devils, tornadoes, and tropical and extratropical systems. The opposite of an anticyclone or a high pressure system.

 

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DAWN

The first appearance of light in the eastern sky before sunrise. It marks the beginning of morning twilight. The visual display is created by the scattering of light reaching the upper atmosphere prior to the sun's rise to the observer's horizon.

DAY

Considered a basic unit of time as defined by the earth's motion. It represents the time needed for one complete revolution of the earth about its own axis. Also know as a sidereal day, it is approximately equal to 23 hours, 56 minutes, and 4.09 seconds.

DAYLIGHT SAVINGS TIME

Time as adjusted to achieve longer evening daylight in summer by setting the clocks an hour ahead of the standard time. For New Zealand, Daylight Savings Time starts on the LAST SUNDAY in September at 2am where the clocks are put forward one hour and ends FIRST SUNDAY in April at 3am where the clocks are put back one hour. The time zone is represented by NZDT (New Zealand Daylight Time +13 hours) during Daylight Savings Time and NZST (New Zealand Standard Time +12 hours) during the rest of the year.

DEBRIS CLOUD

Considered a rotating cloud of debris or dust that is on the ground or near the ground. The debris cloud appearing beneath a thunderstorm will most likely confirm the presence of a tornado.

DEEPENING

Used in describing the history of a low pressure system or an area of cyclonic circulation, it means a decrease in the central pressure of the system. Although it usually describes the action of a pressure system on a constant pressure chart, it also means a surface low is increasing in cyclonic circulation and acquiring more energy. The opposite of filling.

DEGREE

A measure of temperature difference representing a single division on a temperature scale.

DENSITY

The ratio of the mass of a substance to the volume it occupies. In oceanography, it is equivalent to specific gravity and represents the ratio of the weight of a given volume of sea water to that of an equal volume of distilled water at 4.0°C or 39.2°F.

DEPRESSION

In meteorology, it is another name for an area of low pressure, a low, or trough. It also applies to a stage of tropical cyclone development and is known as a tropical depression to distinguish it from other synoptic features.

DEW

Condensation in the form of small water drops that forms on grass and other small objects near the ground when the temperature has fallen to the dew point, generally during the nighttime hours.

DEW POINT

The temperature to which air must be cooled at a constant pressure to become saturated.

DUSK

The period of waning light from the time of sunset to dark.

DUST

Small particles of earth or other matter suspended in the air. It is reported as "DU" in an observation and for wide spread dust on the METAR.

DUST BOWL

The term given to the area of the Great Plains including Texas, Oklahoma, Kansas, Colorado, and New Mexico that was most greatly affected during the Great Drought of the 1930's.

 

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EARTHQUAKE

A sudden, transient motion or trembling of the earth's crust, resulting from the waves in the earth caused by faulting of the rocks or by volcanic activity.

ECLIPSE

The obscuring of one celestial body by another.

An eclipse of the moon occurs when the earth is in a direct line between the sun and the moon. The moon does not have any light of its own, instead, it reflects the sun's light. During a lunar eclipse, the moon is in the earth's shadow. It will often look dim and sometimes copper or orange in colour.

EDDY

A small disturbance of wind in a large wind flow, which can produce turbulent conditions. They can also be areas of warmer air north of the main westerlies or colder air south of the westerlies. In oceanic circulation, it is a circular movement of water usually formed where currents pass obstructions, between two adjacent currents flowing counter to each other, or along the edge of a permanent current.

ELEVATION

The measure of height with respect to a point on the earth's surface above mean sea level. Sometimes referred to as station elevation.

ENVIRONMENT

The sum total of all the external conditions that effect an organism, community, material, or energy.

EYE

The center of a tropical storm or hurricane, characterized by a roughly circular area of light winds and rain-free skies. An eye will usually develop when the maximum sustained wind speeds exceed 78 mph. It can range in size from as small as 5 miles to up to 60 miles, but the average size is 20 miles. In general, when the eye begins to

 

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FAHRENHEIT TEMPERATURE SCALE

A temperature scale where water at sea level has a freezing point of +32°F and a boiling point of +212°F. More commonly used in areas that observe the English system of measurement. Created in 1714 by Gabriel Daniel Fahrenheit (1696-1736), a German physicist, who also invented the alcohol and mercury thermometers.

FAIR

This is a subjective description. Considered as pleasant weather conditions with regard to the time of year and the physical location.

FILLING

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. Although it usually describes the action of a pressure system on a constant pressure chart, it also means a surface low is decreasing in cyclonic circulation and losing its characteristics. The opposite of deepening.

FLASH FLOOD

A flood that rises and falls quite rapidly with little or no advance warning, usually as the result of intense rainfall over a relatively small area. Flash floods can be caused by situations such as a sudden excessive rainfall, the failure of a dam, or the thaw of an ice jam.

FLOOD

High water flow or an overflow of rivers or streams from their natural or artificial banks, inundating adjacent low lying areas.

FLOOD PLAIN

Level land that may be submerged by flood waters.

FOG

A visible aggregate of minute water droplets suspended in the atmosphere at or near the surface of the earth, reducing horizontal visibility to less than 5/8 statute miles. It is created when the temperature and the dew point of the air have become the same, or nearly the same, and sufficient condensation nuclei are present. It is reported as "FG" in an observation and on the METAR.

FOG BANK

A fairly well-defined mass of fog observed in the distance. Most commonly seen at sea, over a lake, or along coastal areas.

FORECAST

A statement of expected future occurrences. Weather forecasting includes the use of objective models based on certain atmospheric parameters, along with the skill and experience of a meteorologist.

FREEZING DRIZZLE

Drizzle, falling as a liquid, but freezing on impact with the colder ground or other exposed surfaces. It is reported as "FZDZ" in an observation and on the METAR.

FREEZING FOG

Used to describe the phenomena when fog is present and the air temperature is below 0°C. It is reported as "FZFG" in an observation and on the METAR.

FREEZING POINT/FREEZE

The process of changing a liquid to a solid. The temperature at which a liquid solidifies under any given set of conditions. Pure water under atmospheric pressure freezes at 0°C or 32°F. It is the opposite of fusion. In oceanography, the freezing point of water is depressed with increasing salinity.

FREEZING PRECIPITATION

Precipitation that is liquid, but freezes upon impact with a solid surface, such as the ground or other exposed surfaces.

FREEZING RAIN

Rain that falls as liquid and freezes upon impact to form a coating of glaze on the colder ground or other exposed surfaces. It is reported as "FZRA" in an observation and on the METAR.

FRONT

The transition zone or interface between two air masses of different densities, which usually means different temperatures. For example, the area of convergence between warm, moist air and cool, dry air.

FRONTAL PASSAGE

It is the passage of a front over a specific point on the surface. It is reflected by the change in dew point and temperature, the shift in wind direction, and the change in atmospheric pressure. Accompanying a passage may be precipitation and clouds. May be referred to as "fropa."

FROST

The covering of ice crystals that forms by direct sublimation on exposed surfaces whose temperature is below freezing.

FROZEN PRECIPITATION

Precipitation that reaches the ground in a frozen state. Examples include snow, snow pellets, snow grains, ice crystals, ice pellets, and hail.

FUNNEL CLOUD

A violent, rotating column of air visibly extending from the base of a towering cumulus or cumulonimbus toward the ground, but not in contact with it. It is reported as "FC" in an observation and on the METAR.

 

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GALE

On the Beaufort Wind Scale, a wind with speeds from 28 to 55 knots (32 to 63 miles per hour). For marine interests, it can be categorized as a moderate gale (28 to 33 knots), a fresh gale (34 to 40 knots), a strong gale (41 to 47 knots), or a whole gale (48 to 55 knots). In 1964, the World Meteorological Organization defined the categories as near gale (28 to 33 knots), gale (34 to 40 knots), strong gale (41 to 47 knots), and storm (48 to 55 knots).

GALE WARNING

A warning for marine interests for impending winds from 28 to 47 knots (32 to 54 miles per hour).

GROUND FOG

Fog created when radiational cooling at the earth's surface lowers the temperature of the air near the ground to or below its initial dew point. Primarily takes place at night or early morning.

GUST

A sudden significant increase in or rapid fluctuations of wind speed. Peak wind must reach at least 16 knots (18 miles per hour) and the variation between peaks and lulls is at least 10 knots (11.5 miles per hour). The duration is usually less twenty seconds.

GUST FRONT

The leading edge of the cool, gusty surface winds produced by thunderstorm downdrafts. Sometimes confused with an outflow boundary.

 

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HAIL

Precipitation that originates in convective clouds, such as cumulonimbus, in the form of balls or irregular pieces of ice, which comes in different shapes and sizes. Hail is considered to have a diameter of 5 millimeter or more; smaller bits of ice are classified as ice pellets, snow pellets, or graupel. Individual lumps are called hailstones. It is reported as "GR" in an observation and on the METAR. Small hail and/or snow pellets is reported as "GS" in an observation and on the METAR.

HAZE

A suspension of fine dust and/or smoke particles in the air. Invisible to the naked eye, the particles reduce visibility by being sufficiently numerous to give the air an opalescent appearance. It is reported as "HZ" in an observation and on the METAR.

HEAT

A form of energy transferred between two systems by virtue of a difference in temperature. The first law of thermodynamics demonstrated that the heat absorbed by a system may be used by the system to do work or to raise its internal energy.

HEAT INDEX

The combination of air temperature and humidity that gives a description of how the temperature feels. This is not the actual air temperature.

HEAT LIGHTNING

Lightning that appears as a glowing flash on the horizon. It is actually lightning occurring in distant thunderstorms, just over the horizon and too far away for thunder to be heard.

HEAT STROKE

Introduced to the body by overexposure to high temperatures, particularly when accompanied by high humidity. The signs of heat stroke include when an individual's body temperature is greater than 105°F, the skin is hot and dry, there is a rapid and irregular pulse, perspiration has stopped, and one has lost consciousness. Seek immediate medical aid. May be called a sun-stroke when caused by direct exposure to the sun.

HEAT WAVE

A period of abnormally and uncomfortably hot weather. It could last from several days to several weeks. The Weather Channel uses the following criteria for a heat wave: a minimum of ten states must have 90°F plus temperatures and the temperatures must be at least five degrees above normal in parts of that area for at least two days or more.

HIGH CLOUDS

A term used to signify cirriform clouds that are composed of ice crystals and generally have bases above 20,000 feet. The main types of high clouds are cirrus,cirrocumulus, and cirrostratus. This altitude applies to the temperate zone. In the polar regions, these clouds may be found at lower altitudes. In the tropics, the defining altitudes for cloud types are generally higher.

HIGH PRESSURE SYSTEM

An area of relative pressure maximum that has diverging winds and a rotation opposite to the earth's rotation. This is clockwise the in Northern Hemisphere and counterclockwise in the Southern Hemisphere. It is the opposite of an area of low pressure or a cyclone.

HUMIDITY

The amount of water vapor in the air. It is often confused with relative humidity or dew point.

HURRICANE

The name for a tropical cyclone with sustained winds of 74 miles per hour (65 knots) or greater in the North Atlantic Ocean, Caribbean Sea, Gulf of Mexico, and in the eastern North Pacific Ocean. This same tropical cyclone is known as a typhoon in the western Pacific and a cyclone in the Indian Ocean.

HYDROMETEOR

Any any form of atmospheric water vapor, including those blown by the wind off the earth's surface. Liquid or solid water formation that is suspended in the air includes clouds, fog, ice fog, and mist.

Drizzle and rain are example of liquid precipitation, while freezing drizzle and freezing rain are examples of freezing precipitation.

Solid or frozen precipitation includes ice pellets, hail, snow, snow pellets, snow grains, and ice crystals.

Water vapor that evaporates before reaching the ground is virga.

Examples of liquid or solid water particles that are lifted off the earth's surface by the wind includes drifting and blowing snow and blowing spray.

Dew, frost, rime, and glaze are examples of liquid or solid water deposits on exposed objects.

 

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ICE

The solid form of water. It can be found in the atmosphere in the form of ice crystals, snow, ice pellets, and hail for example.

ICE CRYSTALS

Precipitation in the form of slowly falling, singular or unbranched ice needles, columns, or plates. They make up cirriform clouds, frost, and ice fog. Also, they produce optical phenomena such as halos, coronas, and sun pillars. May be called "diamond dust." It is reported as "IC" in an observation and on the METAR.

ICE FOG

Fog that is composed of minute ice particles. It occurs in very low temperatures under clear, calm conditions in the polar latitudes and may produce a halo around the sun or moon.

INDIAN SUMMER

A period of abnormally warm weather in mid to late autumn with clear skies and cool nights. A first frost normally precedes this warm spell.

ISALLOBAR

The line of equal change in atmospheric pressure during a certain time period. It marks the change in pressure tendency.

ISOBAR

The line drawn on a weather map connecting points of equal barometric pressure.

ISODROSOTHERM

The line drawn on a weather map connecting points of equal dew point.

 

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JET STREAM

An area of strong winds that are concentrated in a relatively narrow band in the upper troposphere of the middle latitudes and subtropical regions of the Northern and Southern Hemispheres. Flowing in a semi-continuous band around the globe from west to east, it is caused by the changes in air temperature where the cold polar air moving towards the equator meets the warmer equatorial air moving polarward. It is marked by a concentration of isotherms and strong vertical shear.

 

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KELVIN TEMPERATURE SCALE

A temperature scale with the freezing point of +273°K (Kelvin) and the boiling point of +373° K. It is used primarily for scientific purposes. Also known as the Absolute Temperature Scale. Proposed in 1848 by William T. Kelvin, 1st Baron of Largs (1824-1907), Irish-born Scottish physicist and mathematician.

KNOT

A nautical unit of speed equal to the velocity at which one nautical mile is traveled in one hour. Used primarily by marine interests and in weather observations. A knot is equivalent to 1.151 statute miles per hour or 1.852 kilometers per hour.

 

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LANDFALL

The point at which a tropical cyclone's eye first crosses a land mass.

LANDSPOUT

A small, weak tornado, which is not formed by a storm-scale rotation. It is generally weaker than a supercell tornado and is not associated with a wall cloud or mesocyclone. It may be observed beneath cumulonimbus or towering cumulus clouds and is the land equivalent of a waterspout.

LENTICULAR CLOUD

A cloud species which has elements resembling smooth lenses or almonds and more or less isolated. These clouds are caused by a wave wind pattern created by the mountains. They are also indicative of down-stream turbulence on the leeward side of a barrier.

LIGHTNING

A sudden and visible discharge of electricity produced in response to the build up of electrical potential between cloud and ground, between clouds, within a single cloud, or between a cloud and surrounding air.

LOW CLOUDS

A term used to signify clouds with bases below 6,000 feet and are of a stratiform or a cumuliform variety. Stratiform clouds include stratus and stratocumulus. Cumuliform clouds include cumulus and cumulonimbus. This altitude applies to the temperate zone. In the polar regions, these clouds may be found at lower altitudes. In the tropics, the defining altitudes for cloud types are generally higher.

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. Also known as an cyclone, it is the opposite of an area of high pressure, or a anticyclone.

LUNAR ECLIPSE

An eclipse of the moon occurs when the earth is in a direct line between the sun and the moon. The moon does not have any light of its own, instead, it reflects the sun's light. During a lunar eclipse, the moon is in the earth's shadow. It will often look dim and sometimes copper or orange in colour. Also known as a "Blood Moon".

 

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MAXIMUM

The greatest value attained by a function, for example, temperature, pressure, or wind speed. The opposite of minimum.

MEAN SEA LEVEL

The average height of the sea surface water level. For the United States, it is computed by averaging the levels of all tide stages over a nineteen year period, determined from hourly height readings measured from a fix, predetermined reference level. It is used as a basis for determining elevations, as the reference for all altitudes in upper air measurements, and as the level above which altitude is measured by a pressure altimeter for aviation. Often referred to as MSL.

MEAN TEMPERATURE

The average of temperature readings taken over a specified amount of time. Often the average of the maximum and minimum temperatures.

MELTING POINT

The temperature at which a solid substance undergoes fusion, changing from a solid to a liquid state. Contrast with freezing point.

MICROBAROGRAPH

A instrument designed to continuously record a barometer's reading of very small changes in atmospheric pressure.

MICROSCALE

The smallest scale of meteorological phenomena that range in size from a few centimeters to a few kilometers. Larger phenomena are classified as mesoscale. It also refers to small scale meteorological phenomena with life spans of less than a few minutes that affect very small areas and are strongly influenced by local conditions of temperature and terrain.

MIDDLE CLOUDS

A term used to signify clouds with bases between 6,000 and 18,000 feet. At the higher altitudes, they may also have some ice crystals, but they are composed mainly of water droplets. Altocumulus, altostratus, and nimbostratus are the main types of middle clouds. This altitude applies to the temperate zone. In the polar regions, these clouds may be found at lower altitudes. In the tropics, the defining altitudes for cloud types are generally higher.

MILLIBAR (MB)

The standard unit of measurement for atmospheric pressure used by the National Weather Service. One millibar is equivalent to 100 newtons per square meter. Standard surface pressure is 1,013.2 millibars.

MINIMUM

The least value attained by a function, for example, temperature, pressure, or wind speed. The opposite of maximum.

MIST

A collection of microscopic water droplets suspended in the atmosphere. It does not reduce visibility as much as fog and is often confused with drizzle.

MOISTURE

Refers to the water vapor content in the atmosphere, or the total water, liquid, solid or vapor, in a given volume of air.

MOON PHASES, CYCLES AND FULL MOON NAMES

For all the information about the moon phases, cycles and full moon names please visit our moon phase page by clicking here.

MUGGY

A subjective term for warm and excessively humid weather.

 

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NIGHT

The period of the day between dusk and dawn.

NORMAL

The recognized standard value of a meteorological element as it has been averaged in a given location over a fixed number of years. Normals are concerned with the distribution of data within limits of common occurrence. The parameters may include temperatures (high, low, and deviation), pressure, precipitation (rain, snow, etc.), winds (speed and direction), thunderstorms, amount of clouds, percent relative humidity, etc.

 

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OBSERVATION

In meteorology, the evaluation of one or more meteorological elements, such as temperature, pressure, or wind, that describe the state of the atmosphere, either at the earth's surface or aloft. An observer is one who records the evaluations of the meteorological elements.

OVERCAST

The amount of sky cover for a cloud layer that is 8/8ths, based on the summation layer amount for that layer.

OXYGEN (O2)

A colourless, tasteless, odorless gas that is the second most abundant constituent of dry air, comprising 20.946%.

OZONE (O3)

A nearly colourless gas and a form of oxygen (O2). It is composed of an oxygen molecule made up of three oxygen atoms instead of two.

OZONE LAYER

An atmospheric layer that contains a high proportion of oxygen that exists as ozone. It acts as a filtering mechanism against incoming ultraviolet radiation. It is located between the troposphere and the stratosphere, around 9.5 to 12.5 miles (15 to 20 kilometers) above the earth's surface.

 

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PARTLY CLOUDY

The state of the weather when the clouds are conspicuously present, but do not completely dull the sky or the day at any moment. The National Weather Service does not have an amount of sky cover for this condition.

PASCAL

The unit of pressure produced when one newton acts on about one square meter.

PRECIPITATION

Any and all forms of water, liquid or solid, that falls from clouds and reaches the ground. This includes drizzle, freezing drizzle, freezing rain, hail, ice crystals, ice pellets, rain, snow, snow pellets, and snow grains. The amount of fall is usually expressed in inches of liquid water depth of the substance that has fallen at a given point over a specified time period.

PRESSURE

The force per unit area exerted by the weight of the atmosphere above a point on or above the earth's surface.

PRESSURE ALTIMETER

An aneroid barometer calibrated to indicate altitude in feet instead of units of pressure. It is read accurately only in a standard atmosphere and when the correct altimeter setting is used.

PRESSURE ALTITUDE

The altitude in standard atmosphere at which a given pressure will be observed. It is the indicated altitude of a pressure altimeter at an altitude setting of 29.92 inches of mercury, and is therefore the indicated altitude above the 29.92 constant pressure surface.

PRESSURE CHANGE

The net difference between the barometric pressure at the beginning and ending of a specified interval of time, usually the three hour period preceding an observation.

PRESSURE JUMP

A sudden increase in the observed atmospheric pressure or station pressure.

PRESSURE TENDENCY

The pressure characteristic and amount of pressure change during a specified time period, usually the three hour period preceding the observation.

PREVAILING WIND

A wind that blows from one direction more frequently than any other during a given period, such as a day, month, season, or year.

 

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RADAR

Acronym for RAdio Detection And Ranging. An electronic instrument used to detect distant objects and measure their range by how they scatter or reflect radio energy. Precipitation and clouds are detected by measuring the strength of the electromagnetic signal reflected back.

RADIATION

The process by which energy is propagated through any medium by virtue of the wave motion of that medium. Electromagnetic radiation, which emits heat and light, is one form. Sound waves are another.

RAIN

Precipitation in the form of liquid water droplets greater than 0.5 mm. If widely scattered, the drop size may be smaller. It is reported as "R" in an observation and on the METAR. The intensity of rain is based on rate of fall. "Very light" (R--) means that the scattered drops do not completely wet a surface. "Light" (R-) means it is greater than a trace and up to 0.10 inch an hour. "Moderate" (R) means the rate of fall is between 0.11 to 0.30 inch per hour. "Heavy" (R+) means over 0.30 inch per hour.

RAINBOW

A luminous arc featuring all colours of the visible light spectrum (red, orange, yellow, green, blue, indigo, and violet). It is created by refraction, total reflection, and the dispersion of light. It is visible when the sun is shining through air containing water spray or raindrops, which occurs during or immediately after a rain shower. The bow is always observed in the opposite side of the sky from the sun.

RAINFALL

The amount of precipitation of any type, primarily liquid. It is usually the amount that is measured by a rain gauge.

RAIN FOREST

A forest which grows in a region of heavy annual precipitation. There are two major types, tropical and temperate.

RAIN GAUGE

An instrument used to measure the amount of rain that has fallen. Measurement is done in hundredths of inches (0.01").

RELATIVE HUMIDITY

A type of humidity that considers the ratio of the actual vapor pressure of the air to the saturation vapor pressure. It is usually expressed in percentage.

RIDGE

An elongated area of high atmospheric pressure that is associated with an area of maximum anticyclonic circulation. The opposite of a trough.

RIME

The rapid freezing of supercooled water droplets as they touch an exposed object, forming a white opaque granular deposit of ice. It is one of the results of an ice storm, and when formed on aircraft it is called rime icing.

ROLL CLOUD

A relatively rare, low-level, horizontal, tube-shaped cloud. Although they are associated with a thunderstorm, they are completely detached from the base of the cumulonimbus cloud.

 

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SANDSTORM

A strong wind carrying sand particles through the air. They are low level occurences, usually only ten feet in height to not more than fifty feet above the surface. Due to the frequent winds created by surface heating, they are most predominate during the day and die out in the night. Visibility is reduced to between 5/8ths and 6/16ths statute mile, and if less than 5/16ths, then the storm is considered a heavy sandstorm. It is reported as "SS" in an observation and on the METAR.

SATELLITE

Any object that orbits a celestial body, such as a moon. However, the term is often used in reference to the manufactured objects that orbit the earth, either in a geostationary or a polar manner. Some of the information that is gathered by weather satellites, such as GOES9, includes upper air temperatures and humidity, recording the temperatures of cloud tops, land, and ocean, monitoring the movement of clouds to determine upper level wind speeds, tracing the movement of water vapor, monitoring the sun and solar activity, and relaying data from weather instruments around the world.

SATELLITE IMAGES

Images taken by a weather satellite that reveal information, such as the flow of water vapor, the movement of frontal system, and the development of a tropical system. Looping individual images aids meteorologists in forecasting. One way a picture can be taken is as a visible shot, that is best during times of visible light (daylight). Another way is as an IR (infrared) shot, that reveals cloud temperatures and can be used day or night.

SATURATION POINT

The point when the water vapor in the atmosphere is at its maximum level for the existing temperature.

SEA FOG

A type of advection fog which forms in warm moist air cooled to saturation as the air moves across cold water.

SEA ICE

Ice that is formed by the freezing of sea water. It forms first as small crystals, thickens into sludge, and coagulates into sheet ice, pancake ice, or ice floes of various shapes and sizes.

SEA LEVEL

The height or level of the sea surface at any time. It is used as a reference for elevations above and below.

SEA LEVEL PRESSURE

The atmospheric pressure at mean sea level, usually determined from the observed station pressure.

SEASON

A division of the year according to some regularly recurring phenomena, usually astronomical or climatic. For example, in the Northern Hemisphere, winter is said to begin on the winter solstice and end on the vernal equinox when spring begins, covering the months of December, January, and February. In the tropics, there is the dry and the rainy season, depending on the amount of precipitation.

SEVERE WEATHER

Generally, any destructive weather event, but usually applies to localized storms, such as blizzards, intense thunderstorms, or tornadoes.

SEVERE THUNDERSTORM

A thunderstorm with winds measuring 50 knots (58 mph) or greater, 3/4 inch hail or larger, or tornadoes. Severe thunderstorms may also produce torrential rain and frequent lightning.

SHOWER

Precipitation from a convective cloud that is characterized by its sudden beginning and ending, changes in intensity, and rapid changes in the appearance of the sky. It occurs in the form of rain (SHRA), snow (SHSN), or ice (SHPE). It is reported as "SH" in an observation and on the METAR.

SKY

The vault-like apparent surface against which all aerial objects are seen from the earth.

SLEET

Also known as ice pellets, it is winter precipitation in the form of small bits or pellets of ice that rebound after striking the ground or any other hard surface. It is reported as "PE" in an observation and on the METAR.

SLUSH

Snow or ice on the ground that has been reduced to a softy watery mixture by rain and/or warm temperatures.

SNOW

Frozen precipitation in the form of white or translucent ice crystals in complex branched hexagonal form. It most often falls from stratiform clouds, but can fall as snow showers from cumuliform ones. It usually appears clustered into snowflakes. It is reported as "SN" in an observation and on the METAR.

SNOWFALL

The rate at which snow falls, usually expressed in inches of snow depth over a six hour period.

SNOWFLAKES

An ice crystal or an aggregate of ice crystals which fall from clouds.

SNOW FLURRY/FLURRIES

Light showers of snow, generally very brief without any measurable accumulation. May be reported as "SHSN--" in an observation and on the METAR.

SOLAR DAY

The complete rotation of the earth in relation to the sun. Although it varies, an average has determined a mean solar day of 24 hours. It is universally used for civil purposes.

SOLAR ECLIPSE

An eclipse of the sun occurs when the moon is in a direct line between the sun and the earth, casting some of the earth's surface in its shadow. The moon's disk shaped outline appears to cover the sun's brighter surface, or photosphere. That part of the earth that is directly in the moon's shadow will see a total eclipse of the sun, while the areas around it will see a partial eclipse.

SOLSTICE

The point at which the sun is the furthest on the ecliptic from the celestial equator. The point at which sun is at maximum distance from the equator and days and nights are most unequal in duration. The Tropic of Cancer and the Tropic of Capricorn are those parallels of latitude which lies directly beneath a solstice. In the Southern Hemisphere, the winter solstice falls on or about June 21 and the summer solstice on or about December 21.

SPRING

The season of the year which occurs as the sun approaches the summer solstice, and characterized by increasing temperatures in the mid-latitudes. Customarily, this refers to the months of March, April, and May in the North Hemisphere, and the months of September, October, and November in the Southern Hemisphere. Astronomically, this is the period between the vernal equinox and the summer solstice.

STANDARD ATMOSPHERE

A standard atmosphere has been defined by the International Civil Aeronautical Organization (ICAO). It assumes a mean sea level temperature of 15°C a standard sea level pressure of 1,013.25 millibars or 29.92 inches of mercury, and a temperature lapse rate of 0.65°C per 100 meters up to 11 kilometers in the atmosphere.

STANDING CLOUD

Any type of isolated cloud, generally formed over peaks or ridges of mountainous areas, that appears stationary or standing over the terrain.

STORM

An individual low pressure disturbance, complete with winds, clouds, and precipitation. The name is associated with destructive or unpleasant weather. Storm-scale refers to disturbances the size of individual thunderstorms.

SUMMER

Astronomically, this is the period between the summer solstice and the autumnal equinox. It is characterized as having the warmest temperatures of the year, except in some tropical regions. Customarily, this refers to the months of June, July, and August in the North Hemisphere, and the months of December, January, and February in the Southern Hemisphere.

SUNRISE

The daily appearance of the sun on the eastern horizon as a result of the earth's rotation. In the United States, it is considered as that instant when the upper edge of the sun appears on the sea level horizon. In Great Britain, the center of the sun's disk is used instead. Time of sunrise is calculated for mean sea level.

SUNSET

The daily disappearance of the sun below the western horizon as a result of the earth's rotation. In the United States, it is considered as that instant when the upper edge of the sun just disappears below the sea level horizon. In Great Britain, the center of the sun's disk is used instead. Time of sunset is calculated for mean sea level.

 

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TEMPERATE CLIMATE

Climates with distinct winter and summer seasons, typical of regions found between the Tropics of Cancer and Capricorn and the Arctic and Antarctic Circles. Considered the climate of the middle latitudes.

TEMPERATURE

The measure of molecular motion or the degree of heat of a substance. It is measured on an arbitrary scale from absolute zero, where the molecules theoretically stop moving. It is also the degree of hotness or coldness. In surface observations, it refers primarily to the free air or ambient temperature close to the surface of the earth.

THERMAL LOW

Also known as heat low, it is an area of low pressure due to the high temperatures caused by intensive heating at the surface. It tends to remain stationary over its source area, with weak cyclonic circulation. There are no fronts associated with it. An example is the low that develops over southwestern United States and northwestern Mexico during the summer months.

THERMOMETER

An instrument used for measuring temperature. The different scales used in meteorology are Celsius, Fahrenheit, and Kelvin or Absolute.

THUNDER

The sound emitted by rapidly expanding gases along the channel of a lightning discharge. Over three-quarters of lightning's electrical discharge is used in heating the gases in the atmosphere in and immediately around the visible channel. Temperatures can rise to over 10,000 °C in microseconds, resulting in a violent pressure wave, composed of compression and rarefaction. The rumble of thunder is created as one's ear catches other parts of the discharge, the part of the lightning flash nearest registering first, then the parts further away.

THUNDERSTORM

Produced by a cumulonimbus cloud, it is a microscale event of relatively short duration characterized by thunder, lightning, gusty surface winds, turbulence, hail, icing, precipitation, moderate to extreme up and downdrafts, and under the most severe conditions, tornadoes.

THUNDERSTORM ASTHMA

Thunderstorm Asthma is a unique phenomenon which triggers an asthma attack due to environmental conditions directly caused by a local thunderstorm. During a thunderstorm, pollen particles (usually too large to enter the lungs) are picked up by the winds and can absorb moisture before bursting into smaller fragments in the thunder cloud. These smaller pollen fragments are able to pass through and enter the lungs, triggering the asthma attack.

TIME ZONE

The New Zealand main land has two different time zones depending on the time of year. New Zealand Standard Time (NZST) is +12 hours Coordinated Universal Time (UTC) and is used over the winter period. During Summer, New Zealand runs one hour in advance which is known as Daylight Savings Time. The time zone is represented by NZDT (New Zealand Daylight Time +13 hours to UTC).
New Zealand also has four other timezones in its jurisdiction including: Chatham Islands, Tokelau, Cook Islands and Niue.
More information about Daylight Savings Time can be found here.

TORNADO

A violently rotating column of air in contact with and extending between a convective cloud and the surface of the earth. It is the most destructive of all storm-scale atmospheric phenomena. They can occur anywhere in the world given the right conditions, but are most frequent in the United States in an area bounded by the Rockies on the west and the Appalachians in the east.

TOWERING CUMULUS

Another name for cumulus congestus, it is a rapidly growing cumulus or an individual dome-shaped clouds whose height exceeds its width. Its distinctive cauliflower top often mean showers below, but lacking the characteristic anvil of a cumulonimbus, it is not a thunderstorm.

TROPICAL CYCLONE

A warm core low pressure system which develops over tropical, and sometimes subtropical, waters, and has an organized circulation. Depending on sustained surface winds, the system is classified as a tropical disturbance, a tropical depression, a tropical storm, or a hurricane or typhoon.

TROPICAL DEPRESSION

A tropical cyclone in which the maximum sustained surface winds are 38 miles per hour (33 knots) or less. Characteristically having one or more closed isobars, it may form slowly from a tropical disturbance or an easterly wave which has continued to organize.

TROPICAL DISTURBANCE

An area of organized convection, originating in the tropics and occasionally the subtropics, that maintains its identity for 24 hours or more. It is often the first developmental stage of any subsequent tropical depression, tropical storm, or hurricane.

TROPICAL STORM

A tropical cyclone in which the maximum sustained surface winds are from 39 miles per hour (34 knots) to 73 miles per hour (63 knots). At this point, the system is given a name to identify and track it.

TSUNAMI

An ocean wave with a long period that is formed by an underwater earthquake or landslide, or volcanic eruption. It may travel unnoticed across the ocean for thousands of miles from its point of origin and builds up to great heights over shallower water. Also known as a seismic sea wave, and incorrectly, as a tidal wave.

TWILIGHT

Often called dusk, it is the evening period of waning light from the time of sunset to dark. The time of increasing light in the morning is called dawn. Twilight ends in the evening or begins in the morning at a specific time and can be categorized into three areas of decreasing light. Civil twilight is the time in the evening when car headlights need to be turned on to be seen by other drivers. Nautical twilight is when the bright stars used by navigators have appeared and the horizon may still be seen. Astronomical twilight is when the sunlight is still shining on the higher levels of the atmosphere, yet it is dark enough for astronomical work to begin. During dawn, the reverse order occurs until full daylight.

 

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ULTRAVIOLET

Electromagnetic radiation that has a wavelength shorter than visible light and longer than x-rays. Although it accounts for only 4 to 5 percent of the total energy of insolation, it is responsible for many complex photochemical reactions, such as fluorescence and the formation of ozone. Check the latest UV Index readings and sun smart tips by clicking here.

UNSTABLE/ INSTABILITY

Occurs when a rising air parcel becomes less dense than the surrounding air. Since its temperature will not cool as rapidly as the surrounding environment, it will continue to rise on its own.

UPPER AIR/UPPER LEVEL

The portion of the atmosphere which is above the lower troposphere. It is generally applied to the levels above 850 millibars. Therefore, upper level lows and highs, troughs, winds, observations, and charts all apply to atmospheric phenomena above the surface.

 

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VALLEY BREEZE

An anabatic wind, it is formed during the day by the heating of the valley floor. As the ground becomes warmer than the surrounding atmosphere, the lower levels of air heat and rise, flowing up the mountainsides. It blows in the opposite direction of a mountain breeze.

VAPOR TRAIL

A cloudlike streamer or trail often seen behind aircraft flying in clear, cold, humid air. A vapor trail is created when the water vapor from the engine exhaust gases are added to the atmosphere. Also called a contrail, for condensation trail.

VISIBILITY

A measure of the opacity of the atmosphere, and therefore, the greatest distance one can see prominent objects with normal eyesight. The National Weather Service has various terms for visibility. Surface visibility is the prevailing visibility determined from the usual point of observation. Prevailing visibility is considered representative of visibility conditions at the station. Sector visibility is the visibility in a specified direction that represents at least a 45 degree arc of the horizon circle. Tower visibility is the prevailing visibility determined from the airport traffic control tower (ATCT) at stations that also report surface visibility.

 

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WARM

To have or give out heat to a moderate or adequate degree. A subjective term for temperatures between cold and hot. In meteorology, an air parcel that is warm is only so in relation to another parcel.

WARM FRONT

The leading edge of an advancing warm air mass that is replacing a retreating relatively colder air mass. Generally, with the passage of a warm front, the temperature and humidity increase, the pressure rises, and although the wind shifts (usually from the southwest to the northwest in the Northern Hemisphere), it is not as pronounced as with a cold frontal passage. Precipitation, in the form of rain, snow, or drizzle, is generally found ahead of the surface front, as well as convective showers and thunderstorms. Fog is common in the cold air ahead of the front. Although clearing usually occurs after passage, some conditions may produced fog in the warm air.

WARM HIGH

A high pressure system that has its warmest temperatures at or near the center of circulation. Contrast with a cold high.

WARM LOW

A low pressure system that has its warmest temperatures at or near the center of circulation. Also referred to as a warm core low.

WARNING

A forecast issued when severe weather has developed, is already occurring and reported, or is detected on radar. Warnings state a particular hazard or imminent danger, such as tornadoes, severe thunderstorms, flash and river floods, winter storms, heavy snows, etc.

WATCH

A forecast issued well in advance of a severe weather event to alert the public of the possibility of a particular hazard, such as tornadoes, severe thunderstorms, flash and river floods, winter storms, or heavy snows.

WEATHER

The state of the atmosphere at a specific time and with respect to its effect on life and human activities. It is the short term variations of the atmosphere, as opposed to the long term, or climatic, changes. It is often referred to in terms of brightness, cloudiness, humidity, precipitation, temperature, visibility, and wind,

WEATHERING

The decay and breakup of rocks on the earth's surface by natural chemical and mechanical processes. The mechanical action includes large changes of temperature, extreme temperatures, frost, or the impact of wind borne sand or water. Chemical action includes the chemical reactions between atmospheric constituents in a moist environments or in rain water. Biological agents are mainly fungi which attack organic material.

WEATHER VANE

Originally used as a wind vane, it is an instrument that indicates the wind direction. The name developed based on observations on what kind of weather occurred with certain wind directions. Creative designs often adorn the tops of barns and houses.

WHIRLWIND

A small-scale, rapidly rotating column of wind, formed thermally and most likely to develop on clear, dry, hot afternoons. Often called a dust devil when visible by the dust, dirt or debris it picks up. Also slang for a landspout or a tornado.

WHITEOUT

When visibility is near zero due to blizzard conditions or occurs on sunless days when clouds and surface snow seem to blend, erasing the horizon and creating a completely white vista.

WIND

Air that flows in relation to the earth's surface, generally horizontally. There are four areas of wind that are measured: direction, speed, character (gusts and squalls), and shifts. Surface winds are measured by wind vanes and anemometers, while upper level winds are detected through pilot balloons, rawin, or aircraft reports.

WIND CHILL INDEX

The calculation of temperature that takes into consideration the effects of wind and temperature on the human body. Describes the average loss of body heat and how the temperature feels. This is not the actual air temperature.

WIND DIRECTION

The direction from which the wind is blowing. For example, an easterly wind is blowing from the east, not toward the east. It is reported with reference to true north, or 360 degrees on the compass, and expressed to the nearest 10 degrees, or to one of the 16 points of the compass (N, NE, WNW, etc.).

WIND SHEAR

The rate of wind speed or direction change with distance. Vertical wind shear is the rate of change of the wind with respect to altitude. Horizontal wind shear is the rate of change on a horizontal plane.

WIND SHIFT

The term applied to a change in wind direction of 45 degrees or more, which takes place in less than 15 minutes. It may the result of a frontal passage, from katabatic winds, sea breezes, or thunderstorms, and in some instances, the change may be gradual or abrupt.

WIND SPEED

The rate of the motion of the air on a unit of time. It can be measured in a number of ways. In observing, it is measured in knots, or nautical miles per hour. The unit most often used in the United States is miles per hour.

WIND VANE

An instrument that indicates the wind direction. The end of the vane which offers the greatest resistance to the motion of the air moves to the downwind position.

WINTER

Astronomically, this is the period between the winter solstice and the vernal equinox. It is characterized as having the coldest temperatures of the year, when the sun is primarily over the opposite hemisphere. Customarily, this refers to the months of December, January, and February in the North Hemisphere, and the months of June, July, and August in the Southern Hemisphere.

WINTER STORM

Any one of several storm systems that develop during the late fall to early spring and deposit wintry precipitation, such as snow, freezing rain, or ice.


Weather Forecast Reference
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The following are the possible weather forecasts used by this website and their respective icons. This site bases the forecast upon the current weather readings gathered from the station. Therefore the predicted forecast can change frequently.

Weather Forecasts and Icons

Weather Icon By NightWeather Icon By Day Forecast0=Not available

Weather Icon By NightWeather Icon By Day Forecast1=Settled fine

Weather Icon By NightWeather Icon By Day Forecast2=Fine weather

Weather Icon By NightWeather Icon By Day Forecast3=Becoming fine

Weather Icon By NightWeather Icon By Day Forecast4=Fine, becoming less settled

Weather Icon By NightWeather Icon By Day Forecast5=Fine, possible showers

Weather Icon By NightWeather Icon By Day Forecast6=Fairly fine, improving

Weather Icon By NightWeather Icon By Day Forecast7=Fairly fine, possible showers early

Weather Icon By NightWeather Icon By Day Forecast8=Fairly fine, showery later

Weather Icon By NightWeather Icon By Day Forecast9=Showery early, improving

Weather Icon By NightWeather Icon By Day Forecast10=Changeable, mending

Weather Icon By NightWeather Icon By Day Forecast11=Fairly fine, showers likely

Weather Icon By NightWeather Icon By Day Forecast12=Rather unsettled clearing later

Weather Icon By NightWeather Icon By Day Forecast13=Unsettled, probably improving

Weather Icon By NightWeather Icon By Day Forecast14=Showery, bright intervals

Weather Icon By NightWeather Icon By Day Forecast15=Showery, becoming less settled

Weather Icon By NightWeather Icon By Day Forecast16=Changeable, some precipitation

Weather Icon By NightWeather Icon By Day Forecast17=Unsettled, short fine intervals

Weather Icon By NightWeather Icon By Day Forecast18=Unsettled, precipitation later

Weather Icon By NightWeather Icon By Day Forecast19=Unsettled, some precipitation

Weather Icon By NightWeather Icon By Day Forecast20=Mostly very unsettled

Weather Icon By NightWeather Icon By Day Forecast21=Occasional precipitation, worsening

Weather Icon By NightWeather Icon By Day Forecast22=Precipitation at times, very unsettled

Weather Icon By NightWeather Icon By Day Forecast23=Precipitation at frequent intervals

Weather Icon By NightWeather Icon By Day Forecast24=Precipitation, very unsettled

Weather Icon By NightWeather Icon By Day Forecast25=Stormy, may improve

Weather Icon By NightWeather Icon By Day Forecast26=Stormy, much precipitation

Icons for Weather Extremes / Weather Warnings

Extreme Weather Icon Heavy Prolonged Rain

Extreme Weather Icon High Rain Rate

Extreme Weather Icon Thunder and Hail

Extreme Weather Icon Thunder

Extreme Weather Icon Hail

Extreme Weather Icon Snow Showers

Extreme Weather Icon Snow

Extreme Weather Icon Sleet

Extreme Weather Icon Drizzle

Extreme Weather Icon High Wind Levels

Extreme Weather Icon Thunder Storms

Extreme Weather Icon Sub Zero Warning

Extreme Weather Icon High Temperatures

Extreme Weather Icon Frost Warning

Extreme Weather Icon Fog / Low Cloud

Extreme Weather Icon Dust

Extreme Weather Icon Haze

Extreme Weather Icon Smoke

Moon

Moon PhaseNew Moon

Moon PhaseWaxing Crescent

Moon PhaseFirst Quarter

Moon PhaseWaxing Gibbous

Moon PhaseFull Moon

Moon PhaseWaning Gibbous

Moon PhaseLast Quarter

Moon PhaseWaning Crescent

please visit our moon phase page for more information regarding the moon

Wind

Calm = Beaufort Scale 0
Light air = Beaufort Scale 1
Light breeze = Beaufort Scale 2
Gentle breeze = Beaufort Scale 3
Moderate breeze = Beaufort Scale 4
Fresh breeze = Beaufort Scale 5
Strong breeze = Beaufort Scale 6
Near gale = Beaufort Scale 7
Gale = Beaufort Scale 8
Strong gale = Beaufort Scale 9
Storm = Beaufort Scale 10
Violent storm = Beaufort Scale 11
Hurricane = Beaufort Scale 12

Trends

Rising very rapidly
Rising quickly
Rising
Rising slowly
Steady
Falling slowly
Falling
Falling quickly
Falling very rapidly