Temperature differences cause air movement {wind}|. Hot air rises, and cool air falls.
mountains
Wind goes up mountains by day, because top heats first, and goes down by night, because top cools first.
land and sea
During day, wind goes from sea to land, as land heats first and air rises from it. At night, wind goes from land to sea, because water's high heat capacity causes sea to stay warmer longer.
ocean
Jet streams and polar winds make oceans flow clockwise in Northern Hemisphere and counterclockwise in Southern Hemisphere, making west coasts dry near equator and wet near pole, and east coasts humid, with big storms.
Earth rotation
Warm air at equator rises and flows toward poles under tropopause. Cold air at poles stays near ground and moves toward equator. Earth rotation makes air at surface flow from east to west in Arctic and east to west in equatorial zone.
Equatorial hot air rises and flows north as cold air from north slides under it, while spinning Earth spins these masses clockwise in Northern Hemisphere and counterclockwise in Southern Hemisphere. Middle, temperate latitudes have no steady surface winds but usually two or three great swirls, with eddies.
Tropical-cyclone wind speed has score 0 to 12 {Beaufort scale}|, or 0 to 17, for 0 to 200 miles per hour.
High-pressure swirls {cell, air}| are more near poles and in subtropics. Low-pressure cells are more in temperate zones.
Earth rotation causes {Coriolis force} air-spin direction.
Tropical-cyclone centers {eye, storm}| are calm and several kilometers wide.
Cold-air mass and warm-air mass can contact {front, air}| when air masses start to move. Polar easterlies can meet southern westerlies {polar front}. At fronts, warm air rises and cools to make clouds and precipitation.
Cold air can replace warm air {cold front}|, or cold-air masses can move into regions. Cold fronts bring rolling dark clouds and lightning, moving fast and steep, as cold air tunnels under warm air, with hard rain. Cold fronts first make cumulonimbus clouds and later make dark low clouds and small strong storms. Cold fronts can make squall lines, from which can come tornados.
Warm air masses can move into regions {warm front}|. Warm fronts first bring high clouds, because warm air goes over cold-air top, and then low clouds, moving slow and long with steady rain. Warm fronts first make cirrus clouds, then cirrostratus clouds, then altostratus clouds, and then nimbostratus clouds, with broad light rain.
Objects can be downwind {leeward}|.
Objects can be upwind {windward}|.
Winds go clockwise around high-pressure region near Azores. Winds {Arctic Oscillation} (AO) go counterclockwise around low-pressure region near Iceland. If low pressure is very low, north Europe, north Asia, and Alaska receive warm wind, and Greenland, east Canada, and south Europe receive cold wind.
Yugoslavia mountains make cold air {bora} that flows to Adriatic Sea.
Warm winds {brickfielder} can be in Australia.
Squalls {bull's eye squall} can be at Cape of Good Hope.
Strong winds {buran} can be in Russia.
Warm day winds {chinook}| can come down east Rocky Mountains, because that side receives no sunlight and is cool.
Warm air surrounded by cold air rises and spins counterclockwise {cyclone}| in Northern Hemisphere or clockwise in Southern Hemisphere. Earth rotation causes spin direction. Warm air can hold more water than cold air. As warm moist air rises, it cools and condenses water, causing precipitation.
anticyclone
If surrounded by warm air, cold air falls and spins clockwise {anticyclone} in Northern Hemisphere or counterclockwise in Southern Hemisphere. Cold air is drier, so as it rises, it causes clear skies.
density
In Northern Hemisphere, warm air goes north to cooler regions and rises, because it is less dense, and cool air goes south to warmer regions and falls, because it is more dense. Moving air masses can cause air to swirl counterclockwise or clockwise. Cyclone makes warmer, wetter air rise, causing low pressure and wet days. Anti-cyclones make colder, dryer air fall, causing high pressure and dry days.
West winds {datoo} can be in Gibraltar.
Just north or south of equator {doldrums}|, winds are weak.
Cool Greek winds {etesian} can blow in summer.
Warm day winds {foehm} can come down north Alps, because that side receives no sunlight and is cool.
strong Swedish wind {frisk vind}.
From 25 to 30 degrees south latitude or north latitude {horse latitudes}|, winds are small.
Temperate-zone high-altitude winds {jet stream}| flow east at lower latitudes and west at higher latitudes.
Japan has gentle breezes {matsukaze} in pines.
Rhone-River-valley glacier makes cold air {mistral}| that flows to Mediterranean Sea.
Winds go clockwise around high-pressure region near Azores. Winds {North Atlantic Oscillation} (NAO) go counterclockwise around low-pressure region near Iceland. If low pressure is very low, north Europe, north Asia, and Alaska receive warm wind, and Greenland, east Canada, and south Europe receive cold wind.
Hot dry summer winds {Santa Ana}| can be in California.
Sahara Desert heats wind {sirocco}|, which picks up water from Mediterranean Sea and rains on Italy.
Winds {solano} can be in Spain.
Equator east-to-west winds {trade wind}| are steady at low altitude.
Japan has strong winds {tsumuji}.
Winds {vento coado} can flow on Portuguese hills.
Humid winds {waimea} are in Hawaii.
Winds {williwaw} can blow in Alaska.
gentle warm wind {zephyr}|.
Hot dry winds {zonda} from Andes Mountains can blow across Argentina pampas.
Winds {gale}| can blow from 51 to 102 kilometers per hour.
Desert sandstorms have high humidity, low temperature, and 45-mph winds {haboob}, such as along Nile River.
In Caribbean Sea, cool air can surround warm moist air that rises faster, spinning into tropical cyclones {hurricane}| with winds up to 200 mph. About 48 hurricanes and typhoons happen a year, usually in late summer.
In Southeast Asia, warm land and cool sea causes summer storms {monsoon}|, but October to April is cool and dry.
In northeast USA, northeastern winds {northeaster}| can bring storms.
Sandy hot strong winds {simoom}| can be in Sahara and Arabian deserts.
Cool winds {squall}| can come suddenly and finish soon, typically with rain or snow.
Strong cold fronts can cause funnel-shaped clouds {tornado}| {whirlwind}, 300 to 600 feet diameter, with 200 mile per hour winds. Tornadoes move 25 miles per hour and travel up to 100 miles. Tornadoes are mostly in central USA and in Australia. 1500 tornadoes happen each year.
Pacific Ocean and Indian Ocean have tropical cyclones {typhoon}|. About 48 hurricanes and typhoons happen a year, usually in late summer.
Squall lines can make sea tornados {waterspout}|.
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Date Modified: 2022.0225