MONSOON The seasonal shift of winds created by the great annual temperature variation that occurs over large land areas in contrast with associated ocean surfaces. The monsoon is associated primarily with the moisture and copious rains that arrive with the southwest flow across southern India. The name is derived from the word mausim, Arabic for season. This pattern is most evident on the southern and eastern sides of Asia, although it does occur elsewhere, such as in the southwestern United States.
They have been seen only during twilight dusk and dawn during the summer months in the higher latitudes. They may appear bright against a dark night sky, with a blue-silver color or orange-red.
These winter weather events are notorious for producing heavy snow, rain, and tremendous waves that crash onto Atlantic beaches, often causing beach erosion and structural damage. Wind gusts associated with these storms can exceed hurricane force in intensity.
A nor'easter gets its name from the continuously strong northeasterly winds blowing in from the ocean ahead of the storm and over the coastal areas. An observer is one who records the evaluations of the meteorological elements. It is composed of an oxygen molecule made up of three oxygen atoms instead of two. It acts as a filtering mechanism against incoming ultraviolet radiation.
It is located between the troposphere and the stratosphere, around 9. This includes drizzle, freezing drizzle, freezing rain, hail, ice crystals, ice pellets, rain, snow, snow pellets, and snow grains. The amount of fall is usually expressed in inches of liquid water depth of the substance that has fallen at a given point over a specified time period.
It consists of two thermometers, a wet bulb and dry bulb. May also be referred to as a sling psychrometer. See What is a Psychrometer? RAIN Precipitation in the form of liquid water droplets greater than 0. If widely scattered, the drop size may be smaller. The intensity of rain is based on rate of fall.
It is created by refraction, total reflection, and the dispersion of light. It is visible when the sun is shining through air containing water spray or raindrops, which occurs during or imsfimagestely after a rain shower. The bow is always observed in the opposite side of the sky from the sun.
It is usually expressed in percentage. In meteorology, it is used when discussing the amount of water vapor in a volume of air. It is caused by the temperature difference when the surface of the land is warmer than the adjacent body of water.
Predominate during the day, it reaches its maximum early to mid afternoon. It blows in the opposite direction of a land breeze. SHOWER Precipitation from a convective cloud that is characterized by its sudden beginning and ending, changes in intensity, and rapid changes in the appearance of the sky. SKY The vault-like apparent surface against which all aerial objects are seen from the earth. SLEET Also known as ice pellets, it is winter precipitation in the form of small bits or pellets of ice that rebound after striking the ground or any other hard surface.
SNOW Frozen precipitation in the form of white or translucent ice crystals in complex branched hexagonal form. It most often falls from stratiform clouds, but can fall as snow showers from cumuliform ones. It usually appears clustered into snowflakes.
SPRING The season of the year which occurs as the sun approaches the summer solstice, and characterized by increasing temperatures in the mid-latitudes.
Astronomically, this is the period between the vernal equinox and the summer solstice. Sea-level pressure is the station pressure adjusted for the elevation of the station using a standard formula, and the difference between them will be a constant percentage for each station.
See Setting Station Pressure on a Kestrel. It is characterized as having the warmest temperatures of the year, except in some tropical regions. It is measured on an arbitrary scale from absolute zero, where the molecules theoretically stop moving.
It is also the degree of hotness or coldness. In surface observations, it refers primarily to the free air or ambient temperature close to the surface of the earth. THAW A warm spell of weather when ice and snow melt. To free something from the binding action of ice by warming it to a temperature above the melting point of ice. The different scales used in meteorology are Celsius, Fahrenheit, and Kelvin or Absolute. Over three-quarters of lightning's electrical discharge is used in heating the gases in the atmosphere in and imsfimagestely around the visible channel.
Temperatures can rise to over 10, degrees Celsius in microseconds, resulting in a violent pressure wave, composed of compression and rarefaction.
The rumble of thunder is created as one's ear catches other parts of the discharge, the part of the lightning flash nearest registering first, then the parts further away.
TIDE The periodic rising and falling of the earth's oceans and atmosphere. It is the result of the tide-producing forces of the moon and the sun acting on the rotating earth. This propagates a wave through the atmosphere and along the surface of the earth's waters. It is the most destructive of all storm-scale atmospheric phenomena.
They can occur anywhere in the world given the right conditions, but are most frequent in the United States in an area bounded by the Rockies on the west and the Appalachians in the east. It may travel unnoticed across the ocean for thousands of miles from its point of origin and builds up to great heights over shallower water. Also known as a seismic sea wave, and incorrectly, as a tidal wave.
This same tropical cyclone is known as a hurricane in the eastern North Pacific and North Atlantic Ocean, and as a cyclone in the Indian Ocean.
Although it accounts for only 4 to 5 percent of the total energy of insolation, it is responsible for many complex photochemical reactions, such as fluorescence and the formation of ozone.
If there is enough moisture, then it may condense, forming a cumulus cloud, the first step towards thunderstorm development. Contrast with a downdraft.
In meteorology, it is considered as the part of total atmospheric pressure due to the water vapor content. It is independent of other gases or vapors. Generally, with the passage of a warm front, the temperature and humidity increase, the pressure rises, and although the wind shifts usually from the southwest to the northwest in the Northern Hemisphere , it is not as pronounced as with a cold frontal passage. Precipitation, in the form of rain, snow, or drizzle, is generally found ahead of the surface front, as well as convective showers and thunderstorms.
Fog is common in the cold air ahead of the front. Although clearing usually occurs after passage, some conditions may produced fog in the warm air. See occluded front and cold front. Warnings state a particular hazard or imminent danger, such as tornadoes, severe thunderstorms, flash and river floods, winter storms, heavy snows, etc.
Do you understand the importance of waiting out a haboob? The storm has passed, and the scent in the air says as much. Coined in by Isabel Joy Bear and R. The molecules of decay recombine with the molecules naturally on the mineral surface during dry spells, and can be smelled after a storm because the addition of water allows the mixture of fatty acids, alcohols, and hydrocarbons to be released.
The term petrichor now encompasses the entirety of the smell after rain, however, not just the sharp dusty-decay scent originally described. One of the most abundant components of petrichor gives it a musty, earthy smell.
This scent is the result of the molecule geosmin. Thermal Belts : An area along the middle of a mountain slope that typically experiences the least diurnal variation in temperature and humidity, thus has the highest daily average temperature and the lowest relative humidity.
Thermal Low : Heat Low - An area of low atmospheric pressure due to high temperatures and intensive heating at earth's surface, usually stationary and have weak cyclonic circulation. Thunderhead : Cumulonimbus or ice top cumulus. Thunderstorm : A local storm produced by cumulonimbus clouds accompanied by lightning and thunder Topography : A detailed description of surface features including rivers, lakes, etc.
Tornado : A violently rotating column of air, pendant from a cumulonimbus cloud observed as a funnel cloud. Towering Cumulus : The transitory stage of a cumulus into a cumulonimbus cloud. Transport Winds : Winds in the lower mixed layer, used for smoke dispersal forecasts. Tropical Cyclone : The general term for a cyclone that originates over the tropical oceans. The remnants of these storms occasionally recurve and move into the mid-latitude westerlies, bringing considerable moisture with them.
Tropopause : The boundary between the troposphere and the stratosphere, usually characterized by an abrupt change to a small lapse rate. Trough : An elongated area of relatively low atmospheric pressure, the axis of which is called a trough line. Turbulence : A state of fluid flow in which the instantaneous velocities exhibit irregular and apparently random fluctuations. Upper Air : Generally applied to levels above mb 5, feet.
Upslope Wind : A wind directed up a slope during the hot part of the day. Valley Wind : A wind which ascends a mountain valley during the day. Ventilation Index : This is the product of the mixing height and transport wind speed, and is an indicator of dispersion potential.
Veering Wind : A change in wind direction in a clockwise manner, i. Virga : Water or ice particles falling out of a cloud but evaporating before reaching the ground. Visibility : The greatest distance it is possible to see permanent objects with the unaided eye. Warm Front : A front that moves in such a way that warmer air replaces colder air. Wave : A disturbance propagated by virtue of periodic motions in the atmosphere. Weather : The state of the atmosphere, usually short term, with respect to its effects upon life, property and human activities.
Wetting Rain : Precipitation of. Westerlies : The dominant west to east motion of the atmosphere across the mid latitudes. Wet Bulb Temperature : The temperature an air parcel would have if cooled to saturation. It lies between the dry bulb temperature and the dew point temperature. Whirlwind : A small scale rotating column of air dust devil. Wind : Air in horizontal motion relative to the surface of the earth.
Wind Direction : The direction from which the wind is blowing. Zonal Flow : The flow of air along a latitude circle.
Zone Weather Forecast : A portion of the general fire weather forecast issued on a regular basis during the normal fire season specifically to fit the requirements of fire management needs. These zones or areas are a combination of administrative and climatological areas, usually nearly the size of an individual forest or district.
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Winter Weather. Graphical Hazards. Rain, snow, lightning, hail and thunderstorms all originate from clouds. Find out about types of clouds, how they form, why they appear white, and more here. Dust devils are phenomena that occur when one area on the ground heats up more than surrounding areas. This hotter area then heats the air above it, creating a column of circulating air, which picks up dust and other debris from the ground.
Fog is a fascinating event that occurs when the air temperature cools and condenses water molecules from a gas to a liquid. Frost is a beautiful and majestic phenomenon that is usually one of the first signals that winter is on its way. It requires three things in order to form — higher levels of water vapor in the air, low wind speeds, and low temperatures overnight.
Learn more about this frosty event here.
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