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37 Cards in this Set
- Front
- Back
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What are forces that determine horizontal winds?
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Pressure Gradiant Force (PGF), Coriolis Force (CF), and Frictional Force (F) (surface winds only)
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What is PGF?
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always perpendicular to the countours, always points toward low. Can start stationary air moving. Builds momentum like a rock rolling down a hill
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What is CF?
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Coriolis Force. Caused by the rotation of the eart and will only change the wind's direction. In the northern hemisphere it is to the right of the wind and in the southern hemisphere it is to the left.
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What are upper level winds?
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They blow parallel to the countours
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What are surface winds?
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They blow parallel across the isobars towards low pressure
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What directions do upper level winds blow around high pressure centers in the northern hemisphere?
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Clockwise
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What directions do upper level winds blow around high pressure centers in the southern hemisphere?
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Counterclockwise
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What directions do upper level winds blow around low pressure centers in the southern hemisphere?
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Clockwise
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What directions do upper level winds blow around low pressure centers in the northern hemisphere?
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Counterclockwise
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Where would you expect to find rising air motions? Low pressure or high pressure?
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Low
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Where would you expect to find sinking air motions? Low pressure or high pressure?
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High Pressure
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the _____ is always inward when wind blows in a circular path
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Net force
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What forms on a smaller scale (mesoscale)?
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Thermal Circulations
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What are Thermal Circulations?
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They occur on a smaller scale than the large synoptic scale of upper level and surface winds. On this scale it is often possible to ignore the Coriolis Force.
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Does pressure decrease faster in cold or warm air?
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Cold.
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Where and when do the land breezes and sea breezes blow?
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The breeze blows out from the land to the sea at night. The breeze blows from the sea to the land during the day.
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What creates upper level and surface pressure gradients?
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Horizontal temperature differences
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Where is the ITCZ?
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the equator.
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Where are the horse lattitudes located?
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between 30 and 35 degrees north and south
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Where are the NE and SE trade winds?
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they blow north and west in the southern tropics and south and west in the northern tropics
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Does blowing dust at the ground indicate a strong updraft or downdraft?
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Downdraft
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Would you expect the virga to STRENGTHEN or WEAKEN the vertical air mass below the cloud? Why?
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Strengthen, the evaporating precipitation cools the air making it denser causing it to fall faster
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rotating thunderstorm updraft _______
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mesocyclone
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changing wind speed or direction with distance_______
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wind shear
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narrow, intense thunderstorm downdraft ___________
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microburst
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There are about _______flashes of lightning per second on average over the globe
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100
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About _______ people are killed by lightning in the United States each year
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100
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Pressure in the center of a tornado is about _______ mb lower than the surrounding air
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100
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A typical air mass thunderstorm will last about _______ hour(s
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1
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The top of a thunderstorm reaches an altitude of about _______ km(s).
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10
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Is cloud-to-ground lightning positive or negatively charged?
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negatively
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what is the name for cloud-to-ground lightning discharge?
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stepped leader
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iss the hook echo signal produced by a tornado or a thunderstorm?
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THUNDERSTORM
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the clear sky in the center of hurricanes and thundersorms is caused by _________
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sinking air
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what will a mesocyclone produce?
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a wall cloud
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what scale is used to measure tornado intensity?
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Fujita
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what scale is used to measure hurricane intensity?
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saffir-simpson
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