The difference between showers and rain.
The main difference between rain and showers is that rain is more widespread than showers. Rain at times or occasional rain will affect more of a larger area than frequent showers or scattered showers. Showers do not usually affect all areas with precipitation at the same time like rain. Showers have a shorter duration than rain. Showers begin and end more suddenly than rain. They can be short-lived and separated by blue sky or sun. Showers can be more intense, still covering a smaller area, with hail and heavy rain. Rain tends to be more uniformly steady and moderate or light in intensity.
The National Weather Service expresses the probability of measurable precipitation (0.01 inch) for a given location using percentages and terms such as isolated and scattered. Isolated means a chance of precipitation of less than 30% and scattered is used for a 30% to 50% chance. Likely describes a probability of 60 percent or greater.
30-50% probability: Chance, scattered
60-70% probability: Likely, numerous
Duration, Distribution and Intensity of precipitation and clouds.
Light snow - Greater than 1/2 mile visibility
Moderate snow - 1/4 to 1/2 mile
Heavy snow - Less than 1/4 mile
Clear or sunny - free of clouds or less than one tenth cloudy
Yet another confusing set of weather terms are partly sunny and partly cloudy. According to the National Oceanic and Atmospheric Administration there is no official difference between the two terms. It is important for meteorologists forecasting the weather to emphasize one or the other, to help clarify the meaning of the term used.
Air Pressure - The weight of air pressing down on earth. Air pressure can change from place to place, and this causes air to move, flowing from areas of high pressure toward areas of low pressure. It’s the same as barometric pressure.
Air Mass Thunderstorm - a normal single cell thunderstorm (also called a pulse thunderstorm)
Almanac - A calendar that uses astronomical information and weather data. Almanacs list tide data, give the positions of the stars and forecast weather each day.
Anemometer - A weather instrument that measures the wind speed.
Anticyclone - A high-pressure system that moves in a clockwise motion. These bring you sunny skies.
Areal- refers to an area or region.
Backdoor Cold Front - In the northern hemisphere, weather normally moves from west to east. In the Northeast, most of the time, cold fronts arrive from the northwest or west. But every once in a while an area of high pressure will develop over New England or just off the Northeast coast, since winds move clockwise around the center of high pressure, this air will pass over the relatively cold water of the North Atlantic. As the cooler air moves inland it creates a cold front, sometimes the temperature drop is quite impressive. Because the front is moving northeast to southwest, instead of the normal way, it's called a backdoor cold front.
Base Radial Velocity - This is the velocity of the precipitation either toward or away from the radar (in a radial direction). No information about the strength of the precipitation is given. This product is available for just two radar "tilt" angles, 0.5° and 1.45°. Positive values (warm colors) denote out-bound velocities that are directed away from the radar. Negative values (cool colors) are in-bound velocities that are directed towards the radar. On most radar packages red means moving away from the radar, Green means moving toward the radar. Precipitation moving perpendicular to the radar beam (in a circle around the radar) will have a radial velocity of zero, and will be colored grey. The velocity is given in knots (10 knots = 11.5 mph).
Beaufort Wind Scale - A system of estimating and reporting wind speeds. It is based on the
Blizzard - An intense winter storm with winds of 35 m.p.h. or higher with falling and/or blowing snow to reduce visibility below 1/4 mile for at least three hours.
Blizzard Watch - Alerts the public to the potential for blizzard conditions. Watches are usually issued 12 to 48 hours before the beginning of blizzard conditions.
CAPE - stands for convective available energy. It's a measure of how much energy is available for thunderstorm development. The higher the CAPE the stronger the potential updraft needed to generate thunderstorm, which leads to greater potential for stronger storms.
Cirro - A prefix to cloud-type names for clouds that are at high altitudes and composed of ice crystals.
Clear Sky - When the sky has no clouds.
Clouds - A visible collection of tiny water droplets or, at colder temperatures, ice crystals floating in the air above the surface. Clouds come in many different sizes and shapes. Clouds can form at ground level, which is fog, at great heights in the atmosphere, and everywhere in between. Clouds offer important clues to understanding and forecasting the weather.
Drifting Snow - An uneven amount of snowfall or existing snow on the ground caused by strong winds. Drifting snow can be very dangerous for drivers.
Fujita Scale - The original scale that measures the strength of tornadoes based primarily on the damage tornadoes inflict on human-built structures and vegetation.
F1: winds 73-112 m.p.h. - (Moderate damage) Trees snapped and mobile home pushed off foundations
Glaze - A coating of ice, usually clear and smooth, formed on exposed objects by the freezing of rain, drizzle, or fog.
Global Warming - The theory that increased concentrations of greenhouse gases are causing the Earth’s surface temperature to warm.
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GOM - Gulf Of Mexico.
Hail - A mixture of liquid and frozen precipitation. Hailstones are composed of layers of ice and can become quite large when strong gusts of upward-moving air keep them inside the cloud. As they move around inside the cloud they collide with raindrops, adding layers and growing before they fall to earth.
Hurricane Season - In the Atlantic basin, it's a six-month period from June 1 to Nov. 30, when conditions are favorable for hurricane development.
Ice - A water substance in the solid phase.
Ice Storms - They occur when temperatures below a raining cloud are very cold, causing the raindrops to become supercooled (less than 32 degrees Fahrenheit). Freezing rain covers streets, houses, and trees with heavy layers of ice, causing concern for dangerous driving, and damage from the weight of the ice.
Ice Storm Warning - It’s issued when damaging accumulations of ice are expected during a freezing rain event.
Jet Stream - A strong high level wind found in the atmosphere that can reach speeds in excess of 200 mph, usually occurring 6 to 9 miles above the ground. These winds often steer the movement of surface air masses and weather systems.
Lake Effect Snow Warning - Issued for the snow-belts of Lakes Ontario and Erie when lake effect snow is expected to accumulate to 6 inches or more in 12 hours or less, or 8 inches of snow in 24 hours or less.
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Mesocyclone - A mesocyclone is the rotation in the severe thunderstorm, (typically around 2-6 miles in diameter and often found in the right rear flank of a supercell (or often on the eastern, or front, flank of an HP storm)). A mesocyclone is a warning that very severe weather is about to occur, they do not always produce tornadoes, but 25% to near 40% do. Baseball-sized hail, extremely strong wind gusts are also possible.
Meteor Shower - An event when hundreds of meteors or shooting stars appear in the sky at a specific time.
Meteorologist - A scientist who studies and predicts the weather. Meteorologists use sophisticated equipment, like Doppler radar and supercomputers, but they also rely on old-fashioned sky watching.
Ozone - A form of oxygen that has a weak chlorine odor. Ozone heats the upper atmosphere by absorbing ultraviolet from sunlight. In the troposphere, ozone is a pollutant, but in the stratosphere it filters out harmful ultraviolet radiation.
PWAT- precipitable water, the total amount of liquid in a column of the atmosphere ( from the surface to around 300mb or 30,000 feet) if it were to all fall as rain.
QPF - Quantitative Precipitation Forecast, the expected amount of precipitation that will fall over a specified area.
Sea Breeze - An daytime coastal breeze that blows onshore, from the sea to the land. 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.
Severe Weather - It's any kind of destructive or life-threatening weather event. Thunderstorms that can be destructive, while tornadoes, high winds, hail, excessive rainfall and lightning can be life threatening.
Showers - It’s just rain falling from the sky causing puddles to form on the ground.
Sleet - Solid precipitation in the form of ice pellets form when raindrops, originating in warmer air aloft, freeze as they fall through subfreezing air near the surface of the Earth.
Snow Showers - Brief occurrences of light to moderate snow, which could produce some snowfall accumulations.
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Training - storm after storm moves over the same area, producing heavy rainfall.
V = Wind Speed (mph)
^ = raised to a power (exponential)
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