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Terms in this set (51)
cold frontCold air mass moving towards warmwarm frontWarm air mass moving towards coldstationary frontNo or little recent relative movementoccluded frontCold front meets warm front at large angleDrylinea boundary that separates a moist air mass from a dry air mass. Important factor in severe thunderstorms. Oriented North to South.lighteningResults from strong separation of charge thy builds up between top and bottom of cumulonimbus cloud.Heat lighteningDoes not existthunderstorma storm with thunder and lightning and typically also heavy rain or hail. Contains both updrafts and downdraftsPolar Front TheoryA theory developed by a group of Scandinavian meteorologists that explains the formation, development, and overall life history of cyclonic storms that form along the polar front. Describe interactions between unlike air masses and the related aspects of the mid latitude cyclone.CyclogenesisFormation of low pressure systems. "Kink" in the boundary.IntensificationLow pressure deepens -> distinct warm and cold fronts develop from original polar frontconvergence and frontal liftCloud formation and precipitationMature cyclonesProduce heavy precipitation and severe thunderstorms associated with squall lines. Capable of creating snow, sleet, freezing rain, hail. Winds spiral counterclockwise.Occlusion life cycleEnd of cyclone's life cycle. Takes place at center of the low pressure pulls away from warm and cold fronts.warm conveyor beltoriginates near the surface in the warm sector and flows toward the warm front -Air flowing toward the storm center is displaced aloft until it overrides the warm front where it turns to the right, becoming part of the westerly flow aloftcold conveyor beltlies north of the warm front. It travels westward near the surface, where it ascends and turns clockwise to become part of the westerly upper air flowdry conveyor beltoriginates in the upper troposphere as part of the westerly flow -Air sinks into the trough only to rise over the region of the surface low before continuing east -Integral to maintaining separate cloud bands which give the system its characteristic comma shapeair mass thunderstormA localized thunderstorm that forms in a warm, moist, unstable air mass. This type of storm occurs most frequently in the afternoon in spring and summer.cumulus stage of thunderstormUpdrafts onlyMature stage of thunderstormUpdrafts and downdraftsDissipating stage of thunderstormDowndrafts only. Storm tower falls apart.severe thunderstormA thunderstorm with winds of 58 mph or greater and/or with hail ¾ inch in diameter or larger and/or tornadoMulticellular ThunderstormsThunderstorms can develop into clusters known as this. Groups of storm towers in different stages.squall linea row of severe thunderstormsMesoscale Convective ComplexA slow-moving roughly circular cluster of interacting thunderstorm cells covering an area of thousands of square kilometers that may persist for 12 hours or more.Downbursts (microbursts)-column of sinking air that spreads out after hitting the ground -damaging straight-line windssupercell thunderstormlarge, rotating single-cell thunderstorm, can cause tornadoes, large hail, frequent lightning, heavy rain, strong windsSupercell structureUpdrafts and downdrafts wrapping around each other because of wind shearMesoscale Convective ComplexA slow-moving roughly circular cluster of interacting thunderstorm cells covering an area of thousands of square kilometers that may persist for 12 hours or more.wind shearthe rate of change of wind speed or wind direction over a given distancewall cloudan area of clouds that extends underneath a thunderstorm; attached to a rain-free base (updraft) area of a supercell, formed when cool, humid air is drawn into updrafttropical storma storm with winds of at least 39 miles per hour, cyclone is formed, late summer/early fall, not within 5 degrees of equator bc of Coriolis forcehurricane watchan alert that is given 48 hours in advance to residents that lets them know a hurricane is possiblehurricane warningissued 36 hours in advance of the approaching storm for coastal regions where the hurricane is forecast to make landfall and tropical storm-force winds are imminentHurricane is created by 2 processes1. Piling up of water as high as wind drags surface water forward 2. Low atmospheric pressureSaffir-Simpson ScaleClassifies hurricanes according to wind speed, air pressure in the center, and potential for property damage.cP (continental polar)High latitude, continental interior, cold and dry. Very stable. Minimal cloud cover.cT (continental tropical)Low altitude desserts, hot and dry, very unstable.mP (maritime polar)High-latitude oceans, cold, wet, cloudy, somewhat unstablecA (continental arctic)Highest latitudes, extremely cold, very dry. Extremely unstable, minimal cloud cover.mT (maritime tropical)Subtropical oceans, warm and humid.