Horizontal Vorticity and Convection

Question 1

What are the three terms of the vertical vorticity equation?

Answer 1

1) advection
2) tilting
3) stretching

Question 2

____ horizontal vorticity is generated at the leading edge of the cold pool, causing the cold pool to ___ along the surface

Answer 2

negative | causing cold pool to move (or spread) along the sfc

Question 3

There is ___ pressure underneath cold air, which causes the cold air to accelerate _____

Answer 3

higher pressure | accelerate outward

Question 4

The ambient air flows ___ the cold pool from the east, and is lifted at the ___ edge of the cold pool

Answer 4

flows toward the cold pool | lifted at the leading edge

Question 5

In the absence of any other sources of horizontal vorticity, the lifted air is then guided ___ by the cold pool general circulation

Answer 5

guided rearward

Question 6

In the absence of any generated ____ buoyancy produced by lifting (i.e. if the ambient air does not reach its LFC), the ambient air will not travel any farther above the cold air

Answer 6

positive buoyancy

Question 7

When a cold pool has vertical wind shear, a positive environmental vorticity couples with negative vorticity at the edge of the gust front to develop an ____ ____

Answer 7

updraft jet

Question 8

When the vertical wind shear vector points to the east, it signifies ____ horizontal vorticity

Answer 8

positive horizontal vorticity

Question 9

If the magnitude of the positive horizontal vorticity associated with the ambient shear is the same as the magnitude of the negative horiz vorticity produced along the leading edge of cold air, then the air approaching the cold pool will tend to rise as a ____ ____ ___

Answer 9

vertically-oriented jet (updraft jet)

Question 10

This produces ____ lifting at the leading edge of the cold air than from the case of no ambient vertical wind shear

Answer 10

deeper lifting

Question 11

When the cold pool interacts with vertical wind shear, the ambient air has a much greater chance of being lifted to its ____

Answer 11

LFC

Question 12

Evenly matched, but opposite horiz vorticity in the vorticity dipoles maintains ___ ____

Answer 12

deep updraft

Question 13

The triggering of convective cells is favored along the ____ portion of a spreading cold pool

Answer 13

downshear

Question 14

The strongest, most-lived convective systems will be produced when there is a strong ___ ___ ___ to balance the cold pool generated circulation

Answer 14

LL vertical wind shear

Question 15

____ shear is important in how a storm’s updraft may evolve

Answer 15

environmental shear

Question 16

How can you evaluate environmental wind shear?

Answer 16

plotting a hodograph

Question 17

hodographs depict the _____ ____ of the horiz wind

Answer 17

vertical distribution

Question 18

with hodographs, points are plotted as a function of ___ ____ and ____

Answer 18

wind direction and speed

Question 19

with hodographs, each point represents the ____ wind at a specified elevation

Answer 19

horizontal wind

Question 20

with a hodograph, wind vectors for each level are produced by connecting the hodograph’s ____ origin point with the ____ point

Answer 20

central origin with the plotted point

Question 21

with hodographs, ____ shear vectors are produced by connecting two sequential points

Answer 21

layer shear vectors

Question 22

The ___ ___ is the leading edge of the rain-cooled air in the planetary boundary layer

Answer 22

gust front

Question 23

The gust front forms along ___ ___ of mesoscale domes of rain-cooled air that result from the amalgamation of ____-____ downdrafts from individual thunderstorm cells

Answer 23

leading edges | evaporatively-cooled

Question 24

thunderstorm cold pools are associated with ___-___ and may actually be crudely analyzed on a synoptic surface chart

Answer 24

meso-highs (i.e. bubble highs)

Question 25

The gust front is a ____ discontinuity

Answer 25

density

Question 26

___, ___ surface air flows outward from the meso-high

Answer 26

cooler, denser

Question 27

High theta-e air is uplifted ___ the outward-flowing cold pool

Answer 27

above

Question 28

New convection may form in association with this uplift if the lifted parcels can reach their ____

Answer 28

LFC (level of free convection)

Question 29

____ ____ ___ can play a major role in determining how high a parcel may be lifted prior to reaching its LFC

Answer 29

environmental wind shear

Question 30

gust front passage is characterized by what 5 things?

Answer 30

1) wind shift and abrupt increase in wind speed 2) abrupt temperature drop (most of the time) 3) sharp pressure rise 4) arc cloud (if BL is moist) 5) strong VWS

Question 31

A gust front is a ____ feature

Answer 31

mesoscale

Question 32

The ___ ___ ___ represents the gust front

Answer 32

low cloud line

Question 33

air lifted upward by the gust front produces a ___ ___

Answer 33

shelf cloud

Question 34

What three physical mechanisms control storm structure?

Answer 34

1) buoyancy processes 2) gust front processes 3) dynamic proceses

Question 35

What are two examples of buoyancy processes?

Answer 35

1) lapse rate (CAPE) | 2) moisture stratification

Question 36

Environmental VWS affects the ability of the gust front to trigger new ___ ____

Answer 36

convective elements

Question 37

environmental VWS affects the ability of the updraft to interact with this environmental shear to produce enhanced, ___-___ storm structure

Answer 37

quasi-steady

Question 38

for the storm, shear is relative to the ____ of the storm

Answer 38

motion

Question 39

a storm travelling at the speed of the mean vector wind (MVW) automatically develops an enhanced ____ _____ into its updraft

Answer 39

inflow of BL air

Question 40

the LL air has a strong component of ___ ___ toward the approaching storm

Answer 40

low-level

Question 41

the magnitude of the inflow can be properly matched to the magnitude of the ____ updraft

Answer 41

buoyant updraft

Question 42

in the absence of suitable shear, the inflow will be _____ to sustain the vigorous updraft that might result from large thermal instability

Answer 42

insufficient

Question 43

what are 2 examples of gust front processes?

Answer 43

1) strength of cold pool | 2) strength of LL VWS

Question 44

What are 2 examples of dynamic processes?

Answer 44

1) strength of 4-6 km AGL VWS 2) development of rotational (helical) updrafts and associated favorable vertical pressure gradients on the updraft flank

Question 45

With an ordinary cell, ____ more important in maintaining updraft than ___ processes

Answer 45

buoyancy | dynamic

Question 46

with supercells, ____ processes are more important than ____ in maintaining updraft

Answer 46

dynamic | buoyancy

Question 47

vertical wind shear produces ____ ___ ___

Answer 47

horizontal vorticity tubes

Question 48

horizontal vorticity tubes are incorporated into a ____ ____ and tilt ____

Answer 48

thunderstorm updraft | tilt vertically

Question 49

the updraft begins to rotate in the same sense as the ____ ____ (cyclonic or anticyclonic)

Answer 49

vertical vorticity

Question 50

updraft intensity is _____ within rotating cores

Answer 50

maximized

Question 51

precipitation loading in updraft weakness between rotating cores produces a ____

Answer 51

downdraft

Question 52

a downdraft separates the ____ updraft from the ___ updraft

Answer 52

cyclonic | anticyclonic

Question 53

____ ____ occurs as each updraft sustains a separate storm cell

Answer 53

storm splitting

Question 54

what is the first stage of storm splitting?

Answer 54

cyclonic and anticyclonic updrafts

Question 55

what is the second stage of storm splitting?

Answer 55

the initial storm now splits into two

Question 56

a rotating updraft can cause the storms motion to significantly deviate from the ___ ___ ___

Answer 56

mean vector wind (MVW)

Question 57

with a cyclonically-rotating updraft, the Bernoulli effects produce ___ pressure on the ___ side of the cyclonic updraft in the mid-troposphere

Answer 57

low (high) | right (left)

Question 58

with a cyclonically-rotating updraft, cyclonic storms move to the ____ of the MVW

Answer 58

right

Question 59

with a cyclonically-rotating updraft, ___ supercells are favored within veering vertical wind profiles

Answer 59

SR supercells

Question 60

cyclonically-rotating storms develop a ____ motion (right-mover) relative to MVW

Answer 60

rightward motion

Question 61

with a anti-cyclonically-rotating updraft, the Bernoulli effects produce ____ pressure on the ____ side of the anticyclonic updraft in the mid-troposphere

Answer 61

low (high) | left (right)

Question 62

with a anti-cyclonically-rotating updraft, anticyclonic storm moves to the ___ of the MVW (SL supercell)

Answer 62

left

Question 63

with a no-shear ordinary cell, the gust front rapidly ____ the storm

Answer 63

outruns

Question 64

with a no-shear ordinary cell, the storm is left totally _____ over BL cold pool

Answer 64

entrenched

Question 65

with a moderate-shear multicell, the storm will move downshear at roughly the same speed as the _____ between the sfc and 6 km altitude AGL

Answer 65

MVW

Question 66

with a moderate-shear multicell, new cell growth is enhanced along the ____ portion of the gust front

Answer 66

downshear

Question 67

new cell growth along the downshear portion of the gust front ____ relative flow into the newly-developed cells

Answer 67

increases

Question 68

new cell growth along the downshear portion of the GF ____ the length of time cells stay in the vicinity of strong LL convergence zone and associated lifting near GF

Answer 68

increases

Question 69

for strong-shear supercells, rotation develops on the ___ ___ ___ ____ due to vertical tilting of pre-existing horizontal vorticity within the sheared flow

Answer 69

flank of the updraft

Question 70

for strong-shear supercells, if the VWS extends through the middle-levels of the storm, the rotation dynamically induces a ____ pressure anomaly in the middle troposphere

Answer 70

negative (low) pressure

Question 71

What does NPA stand for?

Answer 71

Negative pressure anomaly

Question 72

the NPA produces a strong _______ pressure gradient which accelerates BL air violently upward

Answer 72

non-hydrostatic

Question 73

rotating updrafts associated with mid-level NPA's are _____ and remain ____ after the storm moves into a more stable environment

Answer 73

long-lived | remain vigorous

Question 74

rotation also causes storm motion to deviate from the ____

Answer 74

MVW

Question 75

_____ shear favors storm splitting as NPA

Answer 75

unidirectional shear

Question 76

____ shear forms at mid-levels within rotating updrafts on both right (cyclonic) and left (anticyclonic) side of original storm

Answer 76

unidirectional shear

Question 77

____ shear has split cells that are nearly identical rotate in opposite directions

Answer 77

unidirectional shear

Question 78

____ shear has a climatologically favored veering shear pattern

Answer 78

curved shear

Question 79

___ shear has strongly veering winds that favor strongly right-moving cells with cyclonic rotation.

Answer 79

curved shear

Question 80

With curved shear, left moving anticyclonic cells are ____ _____

Answer 80

not favored