Category:Weather

This is the category page for weather. Any aviation topics related to weather can be found here.
Wind speed is shown by bars or pennants on weather maps. Each half barb represents 5 knots, full barbs are 10 knots and each pennant is 50 knots.

Trough

A trough is an elongated U-shaped area of low pressure with high pressure on either side which may bring about a gradual wind shift. It is also the V-shape formed by the sharp bending of the isobars along a frontal surface.

Trowal

Trough of Warm Air Aloft. Typically used during winter weather, it is a "tongue" of relatively warm/moist air aloft that wraps around to the north and west of a mature cyclone. It is best analyzed between 750-550 millibars using equivalent potential temperature (theta-e). Areas of intense lift and frontogenesis are commonly associated with trowals, hence they are favoured regions for heavy and/or prolonged precipitation. During a winter storm, the heaviest snowfall amounts frequently occur along and north of the trowal axis. There is warm, moist, stable air in the trowal.
Ref: Trowal Definition

Inversion

When the temperature in the atmosphere warms as it rises
An indication of the presence of wind shear

Atmospheric Diurnal Pressure Variation

It is caused by alternate daytime heating and night-time cooling. Diurnal refers to twice daily.

Pressure Gradient

The rate of change of pressure over a given distance measured at right angles to the isobars. The closer the isobars are to each other, the steeper the pressure gradient.

Saturation

The maximum amount of water vapour that the air can hold at a given temperature.

Veer

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