Chapter 12 Mid-Latitude Cyclones

Question 1

what is a polar front?

Answer 1

boundary separating cold polar air from moderate mid-latitude air

Question 2

what is a mid-latitude cyclone?

Answer 2

forms and moves along polar front

Question 3

what are the 6 stages of development within polar front theory?

Answer 3

1. stationary front
2. frontal wave
3. open wave
4. mature cyclone
5. advanced occlusion
6. cut-off low

Question 4

what happens during the stationary front stage?

Answer 4

wind parallel in opposite directions
-temp contrast
-no low yet

Question 5

what happens during the frontal wave stage?

Answer 5

low pressure forms along stationary front
-cold and warm fronts develop

Question 6

what happens during the open wave stage?

Answer 6

wave opens up where warm front and cold front circle the low

Question 7

what happens during the mature cyclone stage?

Answer 7

tip of cold front catches to warm front=occlusion

Question 8

what happens during the advanced occlusion stage?

Answer 8

more of the cold front catches the warm front

Question 9

what happens during the cut-off low stage?

Answer 9

low pressure system moves on and leaves behind a stationary front

Question 10

what is cyclogenesis?

Answer 10

any development or strengthening of a mid-latitude cyclone

Question 11

what is a bomb?

Answer 11

explosive cyclogenesis, pressure drops by >24mb in 24 hours

Question 12

what is a lee-side low?

Answer 12

forms on the downwind side of the mountain

Question 13

what elements help develop a mid-latitude storm?

Answer 13

1. baroclinic instability
2. upper air support
3. jet stream support

Question 14

what is baroclinic instability?

Answer 14

wind causes temp advection as they follow contour lines (blows across isotherms)

Question 15

what is a barotropic environment?

Answer 15

wind blows parallel to isotherms (no temp advection, stationary front)

Question 16

how does upper-air support a mid-latitude storm?

Answer 16

need divergence aloft to be greater than convergence at the surface

-want surface and upper-level systems to be offset (tilted axis)

Question 17

how do jet streams support a mid-latitude storm?

Answer 17

jet streak has to be over divergence at 500mb

Question 18

what is a polar low?

Answer 18

storms that develop over water behind (poleward of) main polar front

Question 19

what is visible imaging?

Answer 19

how: reflects light
what: white=clouds, fog, snow. only works if sun is above the horizon

Question 20

what is infrared imaging?

Answer 20

how: measure wavelength of emitted energy
what: temp of object colder=high cloud, works 24/7