Windward in the context of "Precipitation (meteorology)"

⭐ In the context of precipitation, the windward side of mountainous terrain is considered particularly susceptible to…

Ad spacer

⭐ Core Definition: Windward

In geography and seamanship, windward (/ˈwɪndwərd/ WIND-wərd, /ˈwɪnərd/ WIN-ərd) and leeward (/ˈlwərd/ LEE-wərd, /ˈljərd/ LEW-ərd) are directions relative to the wind. Windward is upwind from the point of reference, i.e., towards the direction from which the wind is coming; leeward is downwind from the point of reference, i.e., along the direction towards which the wind is going.

The side of a ship that is towards the leeward is its "lee side". If the vessel is heeling under the pressure of crosswind, the lee side will be the "lower side". During the Age of Sail, the term weather was used as a synonym for windward in some contexts, as in the weather gage.

↓ Menu

>>>PUT SHARE BUTTONS HERE<<<

👉 Windward in the context of Precipitation (meteorology)

In meteorology, precipitation is any product of the condensation of atmospheric water vapor that falls from clouds due to gravitational pull. The main forms of precipitation include drizzle, rain, rain and snow mixed ("sleet" in Commonwealth usage), snow, ice pellets, graupel and hail. Precipitation occurs when a portion of the atmosphere becomes saturated with water vapor (reaching 100% relative humidity), so that the water condenses and "precipitates" or falls. Thus, fog and mist are not precipitation; their water vapor does not condense sufficiently to precipitate, so fog and mist do not fall. (Such a non-precipitating combination is a colloid.) Two processes, possibly acting together, can lead to air becoming saturated with water vapor: cooling the air or adding water vapor to the air. Precipitation forms as smaller droplets coalesce via collision with other rain drops or ice crystals within a cloud. Short, intense periods of rain in scattered locations are called showers.

Moisture that is lifted or otherwise forced to rise over a layer of sub-freezing air at the surface may be condensed by the low temperature into clouds and rain. This process is typically active when freezing rain occurs. A stationary front is often present near the area of freezing rain and serves as the focus for forcing moist air to rise. Provided there is necessary and sufficient atmospheric moisture content, the moisture within the rising air will condense into clouds, namely nimbostratus and cumulonimbus if significant precipitation is involved. Eventually, the cloud droplets will grow large enough to form raindrops and descend toward the Earth where they will freeze on contact with exposed objects. Where relatively warm water bodies are present, for example due to water evaporation from lakes, lake-effect snowfall becomes a concern downwind of the warm lakes within the cold cyclonic flow around the backside of extratropical cyclones. Lake-effect snowfall can be locally heavy. Thundersnow is possible within a cyclone's comma head and within lake effect precipitation bands. In mountainous areas, heavy precipitation is possible where upslope flow is maximized within windward sides of the terrain at elevation. On the leeward side of mountains, desert climates can exist due to the dry air caused by compressional heating. Most precipitation occurs within the tropics and is caused by convection.

↓ Explore More Topics
In this Dossier

Windward in the context of Rain

Rain is a form of precipitation where water droplets that have condensed from atmospheric water vapor fall by gravity. Rain is a major component of the water cycle and is responsible for depositing most of the fresh water on the Earth. It provides water for hydroelectric power plants, crop irrigation, and suitable conditions for many types of ecosystems.

The major cause of rain production is moisture moving along three-dimensional zones of temperature and moisture contrasts known as weather fronts. If enough moisture and upward motion is present, precipitation falls from convective clouds (those with strong upward vertical motion) such as cumulonimbus (thunder clouds) which can organize into narrow rainbands. In mountainous areas, heavy precipitation is possible where upslope flow is maximized within windward sides of the terrain at elevation which forces moist air to condense and fall out as rainfall along the sides of mountains. On the leeward side of mountains, desert climates can exist due to the dry air caused by downslope flow which causes heating and drying of the air mass. The movement of the monsoon trough, or Intertropical Convergence Zone, brings rainy seasons to savannah climes.

↑ Return to Menu

Windward in the context of Rain shadow effect

A rain shadow is an area of significantly reduced rainfall behind a mountainous region, on the side facing away from prevailing winds, known as its leeward side.

Evaporated moisture from bodies of water (such as oceans and large lakes) is carried by the prevailing onshore breezes towards the drier and hotter inland areas. When encountering elevated landforms, the moist air is driven upslope towards the peak, where it expands, cools, and its moisture condenses and starts to precipitate. If the landforms are tall and wide enough, most of the humidity will be lost to precipitation over the windward side (also known as the rainward side) before ever making it past the top. As the air descends the leeward side of the landforms, it is compressed and heated, producing Foehn winds that absorb moisture downslope and cast a broad "shadow" of dry climate region behind the mountain crests. This climate typically takes the form of shrub–steppe, xeric shrublands, or deserts.

↑ Return to Menu

Windward in the context of Weather gage

The weather gage (sometimes spelled weather gauge or known as nautical gauge) is the advantageous position of a fighting sailing vessel relative to another. The concept is from the Age of Sail and is now antique. A ship at sea is said to possess the weather gage if it is in any position upwind of the other vessel -- having the wind at their back, speeding progress, when sailing towards the other ship. Proximity with the land, tidal and stream effects and wind variability due to geography (hills, cliffs, etc.) may also come into play.

  • An upwind vessel is able to manoeuvre at will toward any downwind point, since the relative wind then moves aft.
  • The fastest point of sail for a frigate typically have the wind blowing in the direction of travel, allowing that ship greater choice in the distance of separation. They could more easily disengage if damaged, and could more easily optimize for the range of their gunnery.
  • However, in sailing warfare, the leeward ship gained a point of advantage in gunnery under heavier wind. When beating to windward, the vessel experiences heeling under the sideward pressure of the wind. This restricts gunnery, as cannon on the windward side are elevated, while the leeward gun ports aim into the sea or in heavy weather may be awash.
  • Ships seeking to evade capture or attack have the advantage being downwind if they are faster vessels or are close to friendly land -- but in heavier weather a strong disadvantage if there is danger of grounding on a lee shore
  • A vessel downwind of another, in attempting to attack upwind, is constrained to trim sail as the relative wind moves forward and cannot point too far into the wind for fear of being headed. The helm is typically more responsive on a downwind course. Sailing upwind involves frequent changes of sail: more tiring for the crew, more chance for mishap, and more taxing for the helm.
  • A ship with the weather gage, turning downwind to attack, may alter course at will to bring starboard and port guns to appropriate elevations.

The term has had a literary rebirth in the popular seafaring novels of C.S. Forester, Patrick O'Brian and Alexander Kent. One of the last times that weather gage was perhaps a factor in a surface naval engagement was in the Battle of the Denmark Strait in 1941, where the German battleship Bismarck and the heavy cruiser Prinz Eugen held the weather gage over the British battleship HMS Prince of Wales and the battlecruiser HMS Hood. Being upwind, the German ships had the advantage that their rangefinders were drier than the British rangefinders facing the spray. The weather restricted the visual range to much less than the gun range.

↑ Return to Menu