Meso Exam 4

Question 0

How does the forward flank downdraft form?

Answer 0

Large vertical wind shear pushes hydrometeors away from the updraft of the storm. Evaporational cooling causes negative buoyancy and downward motion.

Question 1

For mesocyclone: Region of vertical velocity with a char. width of __ km and magnitude of __ lasting at least __ min and extending over at least half the depth of the ___

Answer 1

3-8, 10^-2 s-1, 20, updraft

Question 2

How long do supercells usually last?

Answer 2

1-4 hours

Question 3

How does a wall cloud form?

Answer 3

Humid, rain cooled air is drawn into the updraft, thus lowering the LCL at that point

Question 4

Which supercell has the weakest upper level winds? Strongest?

Answer 4

HP has weakest, allowing hydrometeors to fall around updraft
LP has strongest, allowing hydrometeors to be pushed away from the updraft
Classic falls in the middle

Question 5

Looking down shear, where is there positive and negative vorticity?

Answer 5

Positive vorticity to the right. Negative to the left

Question 6

What kind of hodograph is an example of crosswise and stream wise?

Answer 6

Straight hodograph is crosswise- shear vector and storm motion are same direction
Curved is stream wise- storm motion is to the left of the shear vector

Question 7

What hodograph contains zero SRH?

Answer 7

Straight (crosswise) because the dot product of two orthogonal vectors (V-c and S) is zero

Question 8

What downdraft leads to the formation of low level mesocyclone? Tornado formation?

Answer 8

FFD, RFD

Question 9

Name the supercell propagation terms from p~ [(du’/dx)^2+(dv’/dy)^2+(dw’/dz)^2]-1/2£’^2+2S•del w’-dB/dz

Answer 9

1st term: fluid extension
2nd term: spin term
3rd term: linear dynamic term
4th term: buoyancy term

Question 10

What term in the propagation equation relates to splitters?

Answer 10

Term B spin term

Question 11

What type of hodographs do splitters and left/right movers look like?

Answer 11

Splitters: straight hodograph (crosswise)

Left/right movers: curved hodographs (streamwise)

Question 12

Which type of MCSs form immediately following convective initiation? Several hours after?

Answer 12

Type 1 is immediately following- widespread forcing along boundary
Type 2 is hours later- isolated cells forming from upscale growth

Question 13

From image 9.8, how can you tell it is trailing stratiform squall line?

Answer 13

Winds from front to rear
Hydrometeors that are small are pushed to back of system
Mid level system relative winds descend within a downdraft

Question 14

How does the relationship between c and u affect the updraft via RKW theory?

Answer 14

c=u: updraft is erect
c>u: updraft is tilted upshear
c<u: updraft is tilted downshear

Question 15

How do strong low pert pressure under the updraft form?

Answer 15

Stronger cold pool leads to stronger updraft which leads to stronger low

Question 16

Why does a strong low perturbation pressure under updraft lead to strong rear inflow jet?

Answer 16

Stronger the low perturbation pressure is, the stronger the horizontal winds are from that low leading to a strong RIJ

Question 17

What is a typical 0-6 km shear value for bow echoes?

Answer 17

> 20 m/s

Question 18

What size and temperature must the MCCs cloud shield be to consider it a MCC?

Answer 18

Continuous IR temp of -32C area of 10^5 km. Interior cold cloud region with temp -52C area of 50,000 km

Question 19

For MCVs, what causes the cool air below and warm air above?

Answer 19

Cold pool causes cool below

Latent heat release causes warm above