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Weather Forecasting 7 Days Ahead

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Types of Severe Weather • Thunderstorms – Lightening – Thunder • Tornadoes • Hurricanes Thunderstorms • Lightning is an electric discharge that occurs between a posively charged area and a negavely charged area. Thunderstorms are very acve electrically. • Thunder is the sound that results from the rapid expansion of air along the lightning strike. Tornadoes • A tornado is a small, spinning column of air that has high wind speeds and low central pressure and that touches the ground. • A tornado starts out as a funnel cloud that pokes through the boom of a cumulonimbus cloud and hangs in the air. The funnel cloud becomes a tornado when it makes contact with Earth’s surface. Hurricanes • How a Hurricane Forms A hurricane begins as a group of thunderstorms moving over tropical ocean waters. Winds traveling in two different direcons meet and cause the storm to spin. • Damage Caused by Hurricanes Hurricanes can cause a lot of damage when they move near or on to land. Wind speeds of most hurricanes range from 120 to 150 km/h. Hurricanes El Nino • El Nino‐ a warm‐water event occurs in the tropical Pacific Ocean where winds shi & push warm surface water toward the west coast of South America • Occurs once every 2 to 7 years & cause dramac climate changes around the Pacific Ocean & nearby areas such as droughts, floods, & tornadoes • The only semi‐reliable way to predict an El Nino is to noce the rising surface temperatures of the tropical parts of the Pacific Ocean Weather Forecasng • Meteorologist‐ sciensts who study the causes of weather & try to predict it • Meteorologists use informaon from many sources including local weather observers, weather balloons, satellites, & weather staons around the world Radio-sonde Satellites Weather stations Radar Weather ship Supercomputer and weather buoys Aviation Forecaster National and International Shipping Global forecast services Forecast Services up to Weather forecasting 7 days ahead. Weather Forecasng • Staon Models are shared from hundreds of locaons and fed to the Naonal Weather Service • The symbols are used to describe a weather condion Weather Forecasng Weather Accuracy • Short‐range forecasts (12 to 72 hours) are quite accurate • Medium‐range forecasts (3 to 7 days) are now fairly reliable, and have shown significant improvement over the last 20 years as technology has improved. • Meteorologists also make long‐range predicons, which aren’t as accurate but were once impossible to do Weather Tools • Meteorologists use several tools to help them predict the weather including: – Weather Balloons – Satellites – Computers to interpret/calculate data – Weather Maps (from other staons, Naonal Weather Service, etc.) Weather Balloons & Satellites • Weather Balloons carry instruments high into the different layers of the atmosphere to collect weather data such as temperature, air pressure, & humidity • The first weather satellite was launched in 1960 • Cameras on weather satellites can photograph Earth’s surface, clouds, storms, & ice & snow cover Computer Forecasts • Can be used to gather & interpret thousands of bits of data about temperature, air pressure, wind speed, & other factors quickly • The computer starts with weather condions reported over a large area, then it works through many calculaons to make a 12 hour , 24 hour, & 36 hour forecast • As new informaon comes in, the forecast is adjusted Reading Weather Maps • A weather map is a “snapshot” of weather condions at a parcular me in a parcular place • There are many different types of weather maps such as computer or radar maps Weather Service Maps • Data from more than 300 local weather staons are complied at the Naonal Weather Service to help produce a map • The curved lines on weather maps connect places where certain weather condions‐ temperature or air pressure‐ are the same Isobars & Isotherms • Isobar‐ lines joining places on the map that have the same air pressure – iso means “equal” & bar means “pressure” – the numbers on the isobars readings are measured in either inches of mercury or in millibars or both Isobars • Isotherms‐ lines joining places that have the same temperature – Iso means “equal” & therm means “heat” – will be labeled with the temperature in Fahrenheit, degrees Celsius, or both Isotherms Newspaper Weather Maps • These are simplified maps produced by the National Weather Service for public use • Standard symbols on weather maps show fronts, areas of high & low pressure, types of precipitation, & temperature (given in Fahrenheit degrees) .
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    More Observations of Small Funnel Clouds and Other Tubular Clouds

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    Anticyclonic - Rotation in a clockwise direction when viewed from above, similar to a high Multiple-Vortex Tornado - A tornado in which two or more condensation funnels or debris clouds are pressure area. Anticyclonic features rotate from right to left when viewed from the ground. present and often rotate around a common center or each other. Anvil - The flat, spreading top of a cumulonimbus, often shaped like a blacksmith’s anvil. Overshooting Top - A dome-like protrusion above a thunderstorm anvil, representing a strong updraft. Beaver('s) Tail - A low cloud band with a relatively broad, flat appearance suggestive of a Power Flash - A blue-green flash that is often a visual indication of damaging winds. beaver's tail. It is attached to a supercell's updraft base and extends to the east or northeast. Rain Foot - A horizontal bulging of a precipitation shaft near the ground, forming a foot-shaped Clear Slot - A local region of clearing skies or reduced cloud cover, indicating an intrusion of drier prominence. It is a visual indication of strong outflow winds. air. A clear slot is often seen on the west or southwest side of a wall cloud and is visual evidence of a rear flank downdraft. Rain-Free Base - A pronounced outward bend of the precipitation shaft near the ground that has a foot-shaped appearance. It is a visual indication of strong outflow winds. Cyclonic - Rotation in a counterclockwise direction when viewed from above, similar to a low pressure area. Cyclonic features rotate from left to right when viewed from the ground.