weather unit: guided notes to powerpoints

Name: _____________________________ Hour:_____ Geophysical . . . Severe Weather

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Guided Notes: Weather Chapter 17: Atmosphere A. Energy in the Atmosphere The __________ energy drives the weather. 1) The __________ heats Earth’s surface 2) Earth’s surface transfers that energy to the __________ 3) Differences in __________ drive the weather. Energy is transferred in three different ways. 1) Radiation _____________________________________________________ _____________________________________________________. 2) Conduction - The transfer of energy through __________ _________ . - Heat always moves from ___________ areas to __________ areas. 3) Convection - The transfer of energy through a __________ or __________ caused by differences in density. - As heat __________ ( ), density __________ ( ). Heat – the __________ movement within a substance Temperature – the __________ movement within a substance Measured by a __________. Units: __________ Demo: Heating Water Identify radiation, conduction, and convection.


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B. The Atmosphere Earth’s atmosphere has four layers identified by changes in __________. 1) Troposphere - Layer closest to Earth’s surface, where weather occurs. - Temperature __________ ( ) with increasing (⇑) altitude. - Air pressure __________ ( ) with increasing (⇑) altitude. 2) Stratosphere - The second layer from Earth’s surface. - Temperature __________ ( ) with increasing (⇑) altitude. Why?: - Air pressure __________ ( ) with increasing (⇑) altitude. 3) Mesosphere - The third layer from Earth’s surface. - Temperature __________ ( ) with increasing (⇑) altitude. - Air pressure __________ ( ) with increasing (⇑) altitude. 4) Thermosphere - The fourth layer from Earth’s surface. - Temperature __________ ( ) with increasing (⇑) altitude. Chapter 19: The Atmosphere in Motion C. Air Pressure A force caused by the __________ of air molecules being pulled to the Earth by _________. - Air pressure is exerted in all directions. - At sea level, air pressure is __________ pounds per square inch (lb/in2) Barometer – weather instrument that measures __________ __________. - Units of Air Pressure 1) 2) 3) What affects air pressure? 1) Altitude As altitude _________ ( ), air pressure _________ ( ) because less air is pushing down from above. 2) Temperature - As temperature __________ ( ), air pressure __________ ( ) because molecules move faster and further from each other. - As temperature __________ ( ), air pressure __________ ( ) because molecules more slower and closer to each other. 3) Humidity definition - ______________________________ _______________________________________


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On weather maps, areas with the same air pressure can be plotted using isobars. Isobar – lines that join areas with __________ pressure. *** Isobars NEVER cross each other!*** Changes in air pressure are linked to predictable changes in the weather.

High Pressure - H

Low Pressure - L

• a.k.a.

• Cool air _________ from the atmosphere.

• Linked to __________ air.

• Cloud __________ .

• Winds blow away from pressure center.

• a.k.a.

• Warm air __________from the surface.

• Linked to __________ air.

• Cloud __________ .

• Winds blow towards pressure center.

D. Wind The movement of air from areas of _________ pressure ( ) to _________ pressure ( ). - Wind speed increases (⇑) as: 1) the pressure difference __________ ( ) or 2) distance between isobars _________ ( ). Anemometer - instrument that measures _________ _________. Wind Vane – instrument that measures _________ _________. Local Winds Definition – Winds that blows for less than 100 km. Mainly caused by differences in __________. 1) Sea Breeze - Starts over __________ and blows onto _________. - Occur during the __________ when __________ warms faster than ________ .


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2) Land Breeze - Starts over __________ and blows onto __________. - Occur during the __________ when __________ cools faster than __________. Winds patterns across the Earth effected by 1) Temperature Differences - At the equator: air is __________, creating an area of _____ pressure. Therefore, air _________. - At the poles: air is _________, creating an area of _____ pressure. Therefore, air ________. Pressure differences = predictable weather patterns. - At the equator: air is hot and humid __________ rainfall. - At the poles: air is cold and dry __________ rainfall. 2) Coriolis Effect Definition – the tendency of objects moving free of Earth’s surface to _________ its path of travel.

- Caused by _________ _________. - In the Northern Hemisphere, objects are deflected to the _________. - The Coriolis Effect is larger closer to the _________.

Winds blowing out of a high (H) pressure system spiral __________. Winds blowing into of a low (L) pressure system spiral __________-_________.

H L


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Chapter 18: Water in the Atmosphere E. Humidity Specific Humidity – the __________ amount of water vapor in the atmosphere. - Hotter air can hold _________ water vapor. Saturation – the point at which air is at the maximum capacity for water vapor Psychrometer – instrument that measures __________ _________ . F. Condensation Condensation – occurs when water turns from a _________ to a _________. - Slows the rate at which water cools Dew Point – the temperature at which saturation occurs and __________ begins, - As humidity __________ ( ), dew point __________ ( ) because the air can hold less water. Condensation occurs when: 1) Presence of Condensation Nuclei definition – tiny particles on which water can condense. 2) Air must cool below its dew point a) Contact with Colder Surface - Advection Fog – warmer air moves over a colder surface and the air temperature _________ water vapor in the air condenses. b) Expansion as it Rises Adiabatic Cooling – air ________ as it rises because the surrounding air pressure _________. - As air __________, it __________ heat. G. Clouds Clouds form when _____ ___________ = _____ _________. H. Precipitation Precipitation – any form of water that falls from a _________ to _______ ___________. - Precipitation falls when water droplets/ice crystals become heavy enough to fall out of a cloud. Rain Gauge – instrument used to measure the amount of precipitation. Precipitation forms when warm, moist air __________ then cools and __________. - Warmer air carries __________ precipitation. - The higher air rises, the ___________ precipitation can form.


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Mountains can promote condensation and precipitation. - Air, forced to a __________ _________, condenses and precipitates on the windward side of the mountain. - On the __________ side, drier air sinks and warms. Weather on the other side of the mountain tends to be drier. Chapter 20: Weather I. Air Masses A body of air in the __________ that has similar characteristics throughout. 1) 2) Air masses are named for where they came from two-part name. - 1st Letter: describes the __________ of the air mass. ‘c’ __________, DRY air ‘m’ ___________, MOIST air - 2nd Letter: describes the __________ of the air mass. ‘A’ __________, VERY COLD. ‘P’ __________, COLD ‘T’ __________, WARM 1) cA Continental Arctic = very cold, very dry 2) cP Continental Polar = cold, dry 3) mP Maritime Polar = cold, moist 4) cT Continental Tropical = warm, dry 5) mT Maritime Tropical = warm, moist J. Fronts Front – the boundary that separates two different air masses 1) Cold Front A _______ air mass replaces a _______ air mass. - Warm air is quickly forced up steep but narrow front boundary. - Air pressure __________ ( ). 2) Warm Front A _______ air mass replaces a _______ air mass. - Warm air is slowly forced up shallow, wide front boundary. - Air pressure __________ ( ).


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3) Occluded Front A _______ air mass catches up to a _______ front. - Warm air is forces to rise above the cooler air below. - Air pressure generally __________ ( ). 4) Stationary Front Occurs when an air mass _______ _________. - Can cause __________ due to continuous rainfall. K. Mid-Latitude Cyclone A _____ pressures system that forms from the interaction of _________. - Drives the weather patterns in a mid-latitudes ( _____ - _____ ). Stages of Formation 1) Stationary Front _____ air mass is separated from _____ air mass. 2) Unstable Stage Air pressure _______ along the frontal boundary, creating a _____ pressure center. 3) Mature Stage Winds blow ___________ into low pressure center. 4) Occluded Stage The _______ front catches up to the _______ front, forming an _______ front. Stages 1 and 2 (Stationary and Unstable) last for _________ hours. Stages 3 and 4 (Mature and Occluded) last for _________ days. The _____ _______ determines the intensity and path of mid-latitude cyclones. - Mid-latitude cyclones generally travel to the __________. L. Thunderstorms Weather event associated with lightning, thunder, and hail. Thunderstorm Formation 1) Cumulus Stage _______ air rises to form a cumulus cloud. Updraft – rising warm air that prevents __________ from reaching the ground. 2) Mature Stage Precipitation becomes heavy enough to fall through the updraft. Downdraft – strong downward movement of air in a thunderstorm. 3) Dissipation Stage The __________ becomes stronger than the _________. Moisture from the ground is cut-off and the cloud starts to _________.


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Dry Line – separates warm, moist air masses ( ____ ) and dry desert air ( _____ ). - Found _______ of the cold front and _______ warm front in a mid-latitude cyclone. - Warm, dry ( ______ ) air behind the dry lines gives the updraft to feed the storm. Lightning – discharge of electricity from a thundercloud. - Caused by collisions between cloud particles as charged particles move past each other, they create a spark that becomes a lightning bolt. Thunder – the time delay between seeing lightning and hearing thunder is due to the different speeds of light and sound. Hail – a form of precipitation that falls as clumps of ice. M. Tornadoes A violently rotating column of air that normally touches the ground Tornado Formation 1) Wind Shear definition – a strong change in wind _______ and _______ with height - Creates a ________, rotating column of air. - Lets the storm develop over a longer period of time. 2) Strong Updraft definition – upward, _______ movement of air. - From the warm, dry ‘_____’ air mass behind the dry line


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3) Updraft Rotation definition – the updraft starts to rotate with the _______ column of air. - The vertical, rotating column of air eventually reaches the ground. Tornado Alley – region of the United States where tornadoes occur most often. - Increased sunlight during ______ and _______ heats the air, making it unstable - Strong wind shear between cool, dry ______ _________ and warm, moist air from the _____ _____ _______. Tornado Safety Tornado (Severe Weather) Watch – issued when conditions are favorable for severe thunderstorms to produce tornadoes. Tornado Warning – issued when a tornado has been _____ by eye or weather radar. N. Hurricanes A large, rotating storm that gets its energy from _______, _______ water. Hurricane Formation 1) Tropical Disturbance - Warm ocean water rises in warm unstable air to generate clusters of thunderstorms. 2) Tropical Depression - Individual thunderstorms start to merge. - Rotation due to _______ _______. - Direction?: 3) Tropical Storm - Low (L) pressure center with clear center (NO eye) 4) Hurricane - A clear eye forms, surrounded by spiral bands of rain and thunder. Hurricanes form during _______ and early ______, when ocean temperatures are warm enough. Hurricanes need unstable ( _______, _______ ) air that occurs close to the equator. Hurricane Impact 1) Storm Surge – the hurricane eye creates a dome of ocean water that _____ the sea level by several meters. 2)


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Hurricane Safety Tropical Storm Watch – issued when tropical storm conditions present a threat to a coastal area within _____ hours. Tropical Storm Warning – issued when tropical storm condition present a threat to a coastal area within _____ hours. Hurricane Watch – issued when hurricane conditions present a threat to a coastal area within _____ hours. Hurricane Warning – issued when hurricane conditions present a threat to a coastal area within ______ hours.

weather unit: guided notes to powerpoints

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