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14 Cards in this Set
- Front
- Back
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What is an Air mass thunderstorm and its 3 stage life cycle. In what air mass are they found?
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cumulus/ updraft stage- rising, hot parcel in humid maritime tropical air, latent heat release, vertical speeds 10-45 mph
mature stage- precipitation, presence of up and down drafts, updraft cloud forms ice precipitation, downdraft: initiated by frictional drag of falling precipitation dissipation stage: rainfall dominates storm, strong downdrafts suppress new updrafts normally found in maritime tropical air masses |
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how do air mass thunderstorms extinguish themselves
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the rain induced downdraft wipes out new cell growth. severe thunderstorms do not though
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What 2 processes cause severe thunderstorm downdrafts?
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a
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What are the ingredients for severe thunderstorms?
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moisture- storm's fuel, growing clouds will release high latent heat
conditionally unstable tropospheric sounding, air stays stable unless it is forcibly lifted low level uplift mechanism- all fronts provide uplift, dry lines, gust fronts from earlier thunderstorms jet streams providing vertical uplift |
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What are the roles of frontal lifting and its importance with conditional instability.
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a
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What are multicells, their structure, appearance, evolution and main weather.
multicells |
clusters of 2-4 air mass type cells, that as a group keep generating new cells by downdrafts
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squall lines
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linear, start on cold fronts but migrate forward into humid air, can contain supercells, usually 300-500 km long
high winds, tornadoes, only if a super cell develops, produce straight line winds up to 100 mph shelf or arcus clouds, roll clouds too preced them |
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mesoscale convective complex
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round circular storm clusters
vampires of the thunderstorm world, form late afternoon, peak intensity at midnight, lifetime 18 hours |
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derecho
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windstorm, long lived squall line having straight line winds, associated with bow echoes, part of larger scale bulging squall line
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what is a supercells primary weather
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violent thunderstorm
form in great plains its updraft can begin rotating: mesocyclone, create large hail easy signature to see on radar |
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Why is wind shear important to supercells? What is a mesocyclone?
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low and high level flows are at right angles
Wind shear favorable for severe weather occurs when low level southeasterly winds and upper level westerly winds occur simultaneously. |
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super cell internal ingredients
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high environmental instability
extreme high wind shear in lower atmosphere, helps create rotating updrat |
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What causes the vault and the hook echo on radar – are they related?
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updraft air moving so fast theres no time for precipitation to form
yes they are |
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Climatology: Where are thunderstorms most frequent in the USA?
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• Peak frequency in FL and Gulf Coast
– air mass thunderstorms, convergence, frequent mT air • Frequency falls to north, stays high to into Plains – Plains: supercells and MCS’s join the tally • Thunderstorms rare west of Rockies – no Gulf moisture |
