Galerne-
A squally northwesterly wind, cold, humid, and showery, that occurs in the rear of a low pressure area over the English Channel and off the Atlantic coast of France and northern Spain.
Gallego-
A cold, piercing, northerly wind in Spain and Portugal.
Gap wind-
A strong, low-level wind through either a relatively level channel between two mountain ranges or a gap in a mountain barrier; originally applied to strong (10–20 m s-1) easterly winds through the Strait of Juan de Fuca between the Olympic Mountains of western Washington State and the mountains of Vancouver Island, British Columbia, Canada. There they have been defined as “a flow of air in a sea level channel that accelerates under the influence of a pressure gradient parallel to the axis of the channel.” As in the case of mountain- gap winds, this term has also been applied to pressure-gradient winds accelerating through a gap in a mountain barrier. The pressure gradient often results from a stable, post-cold-frontal anticyclone approaching the barrier and being partially blocked (see blocking) as it ascends the barrier, except for the flow through the gap or channel. The tehuantepecer of Central America is a well- known gap wind by this definition. These flows have sometimes been referred to as jet-effect wind and canyon wind.
Garbin-
A sea breeze. In southwest France it refers to a southwesterly sea breeze that sets in about 9 A.M., reaches it maximum towards 2 P.M. and ceases about 5 P.M.
Garua-
A dense fog and/or drizzle from low stratus on the west coast of South America. It creates a raw, cold atmosphere that may last for weeks in winter and supplies a limited amount of moisture to the area.
Gending-
A local dry wind in the northern plains of Java, resembling the foehn. It is caused by a wind crossing the mountains near the south coast and pushing between the volcanoes.
Gentle breeze-
In the Beaufort wind scale, a wind with a speed from 7 to 10 knots (8–12 mph) or Beaufort Number 3 (Force 3).
Gharbi-
A fresh westerly wind of oceanic origin in Morocco.
Gharra-
Hard squalls from the northeast in Libya and Africa. They are sudden and frequent and are accompanied by heavy rain and thunder.
Ghibli-
A hot dust-bearing desert wind in Tripolitania (northwestern Libya), similar to the foehn.
Glacier wind-
A shallow gravity wind, along the icy surface of a glacier, caused by the temperature difference between the air in contact with the glacier and free air at the same altitude. The glacier wind does not reverse itself diurnally as do mountain and valley winds, but it reaches its maximum intensity in the early afternoon. The glacier wind is characterized by strongly turbulent flow. See katabatic wind.
Gorge wind-
A gap wind or canyon wind through a gorge.
Gosling blast-
A sudden squall of rain or sleet in England.
Gowk storm-
Any disturbed state of the atmosphere, especially as affecting the earth's surface, implying inclement and possibly destructive weather.
Gradient-
The space rate of decrease of a function. The gradient of a function in three space dimensions is the vector normal to surfaces of constant value of the function and directed toward decreasing values, with magnitude equal to the rate of decrease of the function in this direction.
Gravity wave-
A wave disturbance in which buoyancy (or reduced gravity) acts as the restoring force on parcels displaced from hydrostatic equilibrium.
Gravity wind-
A wind resulting from cold air running or flowing down a slope, caused by greater air density near the slope than at the same altitude some distance horizontally from the slope.
Greco-
An Italian name for the northeast wind. It was given by Roman sailors to the northeast wind in the Gulf of Lions because it came from the direction of the Greek colony of Marsala (Marseilles). Wind names of similar origin are common in the western Mediterranean, for example, gregale.
Green thunderstorm-
Any thunderstorm that is perceived by observers to be green. The perceptually dominant wavelength of light from green thunderstorms ranges from blue- green to yellow-green. The purity of the color is generally low and the physical mechanism that causes the green appearance is not understood. Although green clouds often occur in conjunction with severe weather, there is no evidence to support anecdotal attributions of the cause of this green to specific characteristics of severe storms, such as hail or tornadoes.
Gregale-
The Maltese and best-known variant of a term for a strong northeast wind in the central and western Mediterranean and adjacent European land areas (stronger than the levante).
Ground fog-
1. According to U.S. weather observing practice, a fog that hides less than 0.6 of the sky and does not extend to the base of any clouds that may lie above it. As an obstruction to vision in an aviation weather observation, ground fog is encoded GF. 2. See radiation fog.
Ground inversion-
An air layer with its base at the ground surface and in which temperature increases with height. These often form at night over land under clear skies and are statically stable. See inversion, lapse rate.
Gregau wind-
In the Tirol, an east wind during March and April.
Gully squall-
A nautical term for a violent squall of wind from mountain ravines on the Pacific side of Central America.
Gust-
1. A sudden, brief increase in the speed of the wind. It is of a more transient character than a squall and is followed by a lull or slackening in the wind speed. Generally, winds are least gusty over large water surfaces and most gusty over rough land and near high buildings. According to U.S. weather observing practice, gusts are reported when the peak wind speed reaches at least 16 knots and the variation in wind speed between the peaks and lulls is at least 9 knots. The duration of a gust is usually less than 20 s. 2. With respect to aircraft turbulence, a sharp change in wind speed relative to the aircraft; a sudden increase in airspeed due to fluctuations in the airflow, resulting in increased structural stresses upon the aircraft. 3. (Rare.) Same as cloudburst.
