Weather Glossary

Anticyclonic gloom

Anticyclonic gloom

While high pressure areas are often associated with dry and sunny weather...

CAPE

CAPE

Convective Available Potential Energy (CAPE) is a measure of...

Crepuscular Rays

Crepuscular Rays

Beams of sunlight particularly seen from the rising or...

Drizzle

Drizzle

This is a centuries-old subjective term referring to fine-dropped...

El Nino

El Nino

The name 'El Niño' is widely used to describe the warming...

Fog

Fog

This is a centuries-old subjective term referring to reduced...

Front, Cold

Front, Cold

This boundary typically marks the arrival of lower temperatures...

Frost Hollow

Frost Hollow

During calm, clear nights, heat radiates quickly away from the ground...

Frost, Hoar

Frost, Hoar

When the temperature of hard surfaces (such as roads...

Glory

Glory

This is a halo that appears around the edge of an observer’s...

Haar, Fret

Haar, Fret

These are centuries-old colloquial terms (of Germanic or...

High Pressure

High Pressure

Areas of high atmospheric pressure occur where air is more concentrated...

Instability

Instability

The likelihood that showers will develop is largely determined by how 'stable'...

Kelvin-Helmholtz Clouds

Kelvin-Helmholtz Clouds

These relatively rare clouds resemble evenly-spaced ocean waves...

MJO

MJO

The Madden Julian Oscillation (MJO) is an eastward pulsation...

Petrichor

Petrichor

The smell produced when rain falls on dry earth...

QBO

QBO

The Quasi Biennial Oscillation - is a regular variation in the...

Rime

Rime

Air can sometimes be both below freezing but still saturated with...

Snow

Snow

This is crystallised water that has formed from water vapour around...

Sudden Stratospheric Warming (SSW)

Sudden Stratospheric Warming (SSW)

Every so often in winter time...

Temperature Inversion

Temperature Inversion

When the atmosphere is well-mixed through its depth...

Vorticity

Vorticity

A crucial element in meteorology is the degree of vorticity (or spin)...

Windchill

Windchill

When the air is cold and the wind is blowing, heat is removed from...

Aurora

Aurora

The Aurora Borealis (or Northern Lights) is a dramatic and colourful...

Circumzenithal Arc

Circumzenithal Arc

This is another effect caused as the sun’s rays are refracted by the...

Dew

Dew

Dew neither rises nor falls, but forms instantaneously when...

Drought

Drought

There is no single universal definition of drought...

Explosive Cyclogenesis

Explosive Cyclogenesis

This refers to the rapid intensification of...

Freezing Fog

Freezing Fog

Even when fog occurs when air temperatures are below freezing...

Front, Occluded

Front, Occluded

Where a cold front catches up with a warm front, a wedge of...

Frost, Air

Frost, Air

Often referred to simply as "a frost" an air frost occurs when...

Funnel Cloud

Funnel Cloud

A funnel cloud is a cone-shaped cloud, which extends from the base...

Graupel

Graupel

These are pellets of ice (sometimes known as soft hail)...

Hail

Hail

This is frozen rain...

ITCZ

ITCZ

Beneath the overhead midday sun, heating is at a maximum within...

Jet Stream

Jet Stream

Jet streams are narrow channels of high speed air (which can be...

La Niña

La Niña

'La Niña' or "the girl" is the term adopted for the opposite side of...

Monsoon

Monsoon

While this word is often associated with heavy rainfall...

Polar Low

Polar Low

During winter, outbreaks of intensely cold air can emerge from...

Rainbow

Rainbow

This magnificent 'special effect' is the result of sunlight being scattered...

Sea Breeze

Sea Breeze

In conditions of light wind and strong sunshine land areas can heat...

Solar Cycle

Solar Cycle

The sun goes through a cycle of approximately 11-years between...

Sun Dog/Mock Sun/Parhelion

Sun Dog/Mock Sun/Parhelion

These are subtly-coloured spectra of light that appear as a partial arc...

Tornado Alley

Tornado Alley

This refers to the zone of Plain States in the USA, where tornadoes...

Waterspout

Waterspout

Similar to tornadoes, watersports are funnel clouds which extend down to a water surface

Blizzard

Blizzard

A blizzard is defined as moderate or heavy falling snow...

Coriolis Force

Coriolis Force

This effect results from the rotation of the Earth. The consequence is that air...

Diurnal Range

Diurnal Range

The difference between the daytime maximum and the night-time...

ENSO

ENSO

El Niño Southern Oscillation (ENSO) describes the hand-in-hand...

Fallstreak

Fallstreak

Even when temperatures are below freezing point, clouds often...

Freezing Rain

Freezing Rain

On some occasions, warm, most air can glide over air which is much...

Front, Warm

Front, Warm

This typically marks the arrival of higher temperatures in...

Frost, Ground

Frost, Ground

This occurs when the temperature of the ground surface falls below...

Föehn Effect

Föehn Effect

When moisture-laden air is forced to rise and cool as it blows over...

Gust Front

Gust Front

This is a line of strong and gusty winds that can occur on the outer edge

Heat Island

Heat Island

Urban areas contain high concentrations of concrete, brick and...

Indian Ocean Dipole

Indian Ocean Dipole

This is an oscillating pattern of sea surface temperatures...

Katabatic Winds

Katabatic Winds

At night, particularly under calm conditions and clear skies, heat radiates...

Low Pressure

Low Pressure

Areas of low atmospheric pressure occur where air is less concentrated...

Noctilucent Cloud

Noctilucent Cloud

At a height of around 200,000 feet, in the atmospheric layer...

Polar Vortex

Polar Vortex

Centred over polar regions, this is a circulation of strong winds high up...

Rayleigh Scattering

Rayleigh Scattering

Ever wondered why clear skies are blue?

Shower

Shower

This is a centuries-old subjective term for a brief spell of rainfall...

Sting Jet

Sting Jet

On the rear side of rapidly developing mid-latitude depressions...

Sun Pillar

Sun Pillar

This is a vertical shaft of light that appears most often at sunrise...

Trough

Trough

This denotes a distinct linear zone of relatively low pressure...

Weather "Bomb"

Weather "Bomb"

This refers to the rapid intensification of an area of low pressure...