Mea 444 Final

Front 1

Why are supercells long lived?

Back 1

precip is separated from updraft due to large vertical shear

Front 2

Why is MLCAPE necessary for a tornado?

Back 2

needed for stretching and buoyancy

Front 3

Why is 0-6 km shear necessary for a tornado?

Back 3

basic requirement for supercells

Front 4

Why is 0-1 SRH important for tornadoes

Back 4

enhances low level rotation in the storm (tilting of streamwise vorticity) and dynamic lifting

Front 5

Why is MLLCL important for tornadoes?

Back 5

low LCLs favor warmer cold pools which are more likely to be assoc. w/ tornadoes

Front 6

Why is MLCIN important for tornadoes

Back 6

smaller CIN implies less negative buoyancy below the LFC, meaning surface parcels are easier to converge and stretch

Front 7

Steps in tornado genesis

Back 7

1) develop updraft flanking vorticies 2) storm splits 3) LL mesocyclone forms as storm ingests air with high SRH 4) RFD brings high vort air to surface 5) tornado develops as high vort air is ingested and stretched by the updraft

Front 8

What does a long straight line hodograph mean?

Back 8

1) enough shear for supercells 2) mirror image splitting due to updraft-flanking vorticies 3) storm merges may lead to a squall line with lifting on downstream edge

Front 9

What does long curved hodograph mean?

Back 9

1) enough shear for supercells 2) shear vector turns with height, thus updraft in shear effect strongly favors the right movers 4) dominant right movers, suppressed left movers

Front 10

3.5 updraft

Back 10

c

Front 11

3.5 hook echo

Back 11

a

Front 12

3.5 FFD

Back 12

D

Front 13

3.5 largest hail

Back 13

B

Front 14

3.5 BWER

Back 14

C

Front 15

3.5 main cloud base is at the LCL of air arriving from

Back 15

E

Front 16

3.5 wall cloud is at the LCL of air arriving from

Back 16

D

Front 17

3.5 LP supercell would be missing feature at

Back 17

A

Front 18

3.5 downshear direciton is

Back 18

D

Front 19

vorticity vector is parallel to velocity vector (c or s)

Back 19

stream

Front 20

associated with mirror-image splits (c or s)

Back 20

cross

Front 21

associated with one dominant sign of vertical vorticity in updraft (c or s)

Back 21

stream

Front 22

component usually enhanced by a supercell's forward flank baroclinity (c or s)

Back 22

stream

Front 23

SRH is the integrated flux of (c or s)

Back 23

stream

Front 24

lifetime of hail stone (5)

Back 24

1) ice particle originates and grows in top of cloud via freezing and vapor deposition 2) ice particle falls to area with supercooled water and grows by riming 3) graupel particle fallspeed increases to extent that it can hover in abundant supercooled water 4) when fall speed exceed updraft speed hail stone falls and begins to melt 5) hits surface

Front 25

chain of events for non supercell tornado (4)

Back 25

1) non-mesocyclone tornado 2) pre-existing boundary possesses horizontal shear and thus vort. is non-zero at surface 3) pertubations cause the sheet of shear to roll up into eddies via shearing instability 4) if an updraft develops over a vort. center, convergence and stretching create tornado

Front 26

2 positive aspects of tornado moving to cooler air mass

Back 26

1) more LL shear/ SRH 2) lower LCL heights

Front 27

2 negative aspects of tornado moving to colder air mass

Back 27

1) less cape 2) more CIN

Front 28

Challenging attribute of HSLC (hours to days) (2)

Back 28

1) low CAPE is extremely common condition (many false alarms) 2) low CAPE is very sensitive to small errors in T, Td in model

Front 29

challenging attribute of HSLC (minutes) (2)

Back 29

1) storms tend to be shallower and smaller so not well resolved by radar 2) many storms evolve quickly (no lead time) 3) many tornadoes from QLCS ( harder to identify)

Front 30

1.1 anticyclonic rotation

Back 30

C

Front 31

1.1 divergence

Back 31

A

Front 32

1.1 NW wind

Back 32

E

Front 33

1.1 convergence with cyclonic rotation

Back 33

H

Front 34

dBZ1=40 dBZ2=30 drops same diameter so number

Back 34

10X higher in A

Front 35

dBZ1=40 dBZ2=30 same number of drops so diameter

Back 35

1.5X higher in A

Front 36

Good or bad of initiation of DMC: CIN of -5 J/kg

Back 36

good

Front 37

Good or bad of initiation of DMC: CAPE of 5 J/kg

Back 37

bad

Front 38

Good or bad of initiation of DMC: high RH from surface through mid layers

Back 38

good

Front 39

Good or bad of initiation of DMC: pseudo-adiabatic (moist) lapse rate in layer above LFC

Back 39

bad

Front 40

Good or bad of initiation of DMC: weak vertical wind shear

Back 40

bad

Front 41

Good or bad of initiation of DMC: intersections of mesoscale boundaries

Back 41

good

Front 42

Good or bad of initiation of DMC: upper trop. synoptic ascent

Back 42

bad

Front 43

3 ingredients for convection

Back 43

moisture, instability, lift

Front 44

mesoscale (3)

Back 44

1)R0~1 2) scale where f and Va both matter 3) scale where gradient balance prevails

Front 45

1.9 time LLJ is strongest

Back 45

G

Front 46

1.9 height LLJ is strongest

Back 46

B

Front 47

1.9 height of EML

Back 47

E

Front 48

1.9 time surface winds strongest

Back 48

I

Front 49

1.9 in order for dryline to advance, it is necessary to break inversion at which height?

Back 49

D

Front 50

1.9 height of super adiabatic lapse rate

Back 50

A

Front 51

1.9 time dryline stalls

Back 51

F

Front 52

1.9 height winds will be geostrophic

Back 52

E

Front 53

1.9 time surface heat flux would be most strongly negative

Back 53

G

Front 54

Why does dryline form in Plains? (2)

Back 54

1) midlevel flow off high terrain to west setus up the very dry EML which caps moist sector 2) sets up dryline and enables dryline to move by mixing

Front 55

Why does LLJ form in plains (2)

Back 55

1) day night cycle in the thermal wind over sloping terrain 2) cyclogenesis and synoptic enhancement

Front 56

works best in very weak vertical wind shear (b or pf)

Back 56

B

Front 57

works best in moderate vertical wind shear (b or pf)

Back 57

PF

Front 58

process best explains squall lines (b or pf)

Back 58

PF

Front 59

process is most sensitive to arrangement of cells (b or pf)

Back 59

B

Front 60

primarily an ordinary cell process (b or pf)

Back 60

B

Front 61

primarily a multicell process (b or pf)

Back 61

PF

Front 62

most sensitive to headwind and tailwind effects (b or pf)

Back 62

PF

Front 63

can overcome more CIN and higher LFCs (b or pf)

Back 63

PF

Front 64

found aloft in the trailing stratiform region (MCV, LEV, GFM)

Back 64

MCV

Front 65

has a horizontal scale of 10-40 km (MCV, LEV, GFM)

Back 65

LEV

Front 66

closely linked to tornadoes and severe winds (MCV, LEV, GFM)

Back 66

GFM

Front 67

relies upon planet vort for formation (MCV, LEV, GFM)

Back 67

MCV

Front 68

may survive long after convection decays (MCV, LEV, GFM)

Back 68

MCV

Front 69

mirror image vorticies with vortex line arches (MCV, LEV, GFM)

Back 69

LEV

Front 70

high pressure from buoyancy (2)

Back 70

1) above warm anomaly 2) below cold anomaly

Front 71

high pressure from dynamic

Back 71

splat

Front 72

low pressure from buoyancy (2)

Back 72

1) above cold anomaly 2) below warm anamaly

Front 73

low pressure from dynamic

Back 73

spin

Front 74

development of ordinary cells (6)

Back 74

1) parcel lifted to LFC 2) rapid growth of updraft 3) development of precip 4) development of downdraft 5) appearance of surface gust front 6) end of cell

Front 75

density moves faster if shallow or deep

Back 75

shallow

Front 76

density moves faster if cold or warm

Back 76

cold

Front 77

density moves faster if dry or moist

Back 77

dry

Front 78

Does Coriolis acceleration produce/increase MCS asymmetries

Back 78

yes

Front 79

does dry air aloft produce/increase MCS asymmetries

Back 79

no

Front 80

horizontal environmental heterogenity produce/increase MCS asymmetries

Back 80

yes

Front 81

environment with curved hodograph produce/increase MCS asymmetries

Back 81

yes

Front 82

mature MCV produce/increase MCS asymmetries

Back 82

yes

Front 83

Why can wet microbursts occur under wider range of environmental lapse rates than dry microbursts? (3)

Back 83

1) wet microbursts have ample precip in downdraft 2) plentiful liquid provides evaporative cooling so that parcels remain saturated and descend at moist rate. This keeps them cooler (more neg buoyant) than if they warm at dry adiabatic rate 3) hydrometeor loading can be substantial and it always contributes to a downard acceleration. Dry microbursts don't have this effect

Front 84

How do bow echoes form (5)

Back 84

1) initial storms are initiated and pass through ordinary cell progression 2) shear causes retriggering on preferred flank of outflow, so long lived convective system 3) cold pool becomes strong and cold pool circulation overwhelms environmental shear, lead to a mean front to rear ascending flow branch 4) F to R flow branch advects heated air and grwoing snow reward, creating trailing stratiform region with warm air aloft. This warm air aloft is associated with pressure falls 5) RIJ develops in response to mid level low. as this RIJ impinges upon the convective region the QLCS locally accelerates or bows forward

Front 85

How to forecast for type I MCS (3)

Back 85

1) look for MUCAPE 2) look for MUCIN and lifting mechanism, overrunning along front 3) look at vertical shear, WAA and LLJ along front

Front 86

Fundamentals of Gravity waves (2)

Back 86

1) parcels oscillate about equilibrium level 2) warmer than surroundings up, cooler down

Front 87

What are orographic mountain waves?

Back 87

mountain displaces air, buoyancy tries to restore it

Front 88

What governs whether will go over or be blocked by terrain?

Back 88

Froude Number, speed of mean flow/speed of gravity waves

Front 89

What are physics that govern downslope wind storms? (3)

Back 89

1) background flow and speed of gravity wave must be equal 2) this causes build up of fluid in front of mountain 3) when fluid leaves build up it experiences large PGF, so it accelerates and thins

Front 90

Environmental ingredients for downslope wind storms

Back 90

1) PGF pointed downwind of mountains 2) elevated inversion near mountain top 3) strong cross barrier flow aloft 4) backing wind profile 5) steep slope on lee side of mountain

Front 91

How is thermally and orographic lift different?

Back 91

1) thermal lift creates convergence by pushing winds up both sides of mountain while orographic is caused by forcing flow over mountain 2) no synoptic wind needed for thermal lift

Front 92

Why do thermally driven slope flows occur? (horizontal vorticity)

Back 92

warming close to the surface creates rising motion while cooler air at same elevation but farther from surface sinks and creates horizontal vorticity

Front 93

why do thermally driven slope flows occur? (acceleration perspective) (3)

Back 93

1) low pressure near surface due to near surface warming so PGF towards ground 2) warming causes buoyancy force directly up 3) added together, creates force directly up mountain

Front 94

why large temp range in valley? (2)

Back 94

1) cooler at night because cold air collects due to drainage 2) weak subsidence warming

Front 95

what is the diurnal cycle of clouds in valley

Back 95

1) overnight-fog 2) early morning- fog clears in middle of valley 3) if any clouds, along boundary walls 4) clouds over highest terrain 5) usually cloud free

Front 96

diurnal cycle of winds

Back 96

1) early morning (9 am)- upslope 2) mid afternoon (3 pm)- up valley 3) early evening (9pm)- down slope 4) overnight (3 am) down valley

Front 97

role of gravity waves

Back 97

communicate the existence of the disturbance across the fluid and adjust the flow to a (new) balanced state

Front 98

How does the atmosphere respond
to localized convective latent heating?

Back 98

creates areas of rising and sinking motiondownstream

Front 99

cooling below warming

Back 99

air near ground experiences net ascent, above ground descent