CHAPTER 6: SEVERE WEATHER AND STORM SYSTEMS Flashcards

1
Q

First documented F5 tornado in Canada

A

Eli MB

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2
Q

How long do microscale atmospheric systems last?

A

Only a few hours

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3
Q

How long do synoptic and global atmospheric systems last?

A

Weeks-MONTHS

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4
Q

A direct relationship between ___ and ___ of atmospheric systems.

A

Size and Duration

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5
Q

Storm systems derive energy from (2)

A

Solar heating and condensation

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6
Q

Typical time of day of tornados

A

Late afternoon

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7
Q

Typical duration of tornados

A

5 mins

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8
Q

Typical time of year for tornados

A

April-June

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9
Q

Define Thunderstorms

A

Cumulonimbus cloud that produces lightning and thunder

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10
Q

Where are thunderstorms most frequent?

A

Over tropics

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11
Q

How many thunderstorms worldwide each year?

A

16 million, 2000 in progress at once

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12
Q

Where do thunderstorms typically take place in USA and Canada

A

Great Plains

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13
Q

Define air masses

A

Large body of air with fairly uniform temperature and moisture characteristics

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14
Q

Air masses are classified based on….

A

source area

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15
Q

Define Source area

A

extensive land or ocean surfaces over which an air mass derives its temperature and moisture characterics

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16
Q

Latitudinal position of air masses alters the

A

Temperature

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17
Q

Underlying surfaces of air masses alters the…

A

moisture

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18
Q

2 possible underlying surfaces of air masses

A

C=continental(dry)

m=maritime (wet)

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19
Q

5 possible latitudinal positions of air masses

A
A= ARCTIC
AA= ANTARCTICA
P=POLAR
T= TROPICAL
E= EQUATORIAL

(ACRONYM… PETA-AA)

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20
Q

cA airmass is…

A

Polar high, very cold and dry

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21
Q

cP airmass is…

A

polar high, cold, dryu

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22
Q

mP airmass is…

A

polar high and sub polar low, humid

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23
Q

cT airmass is…

A

subtropical high, hot/dry

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24
Q

mT airmass is….

A

ITCZ… subtropical high/warm, humid

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25
Q

3 types of thunderstorms

A
  1. Single-cell
  2. Multicell
  3. supercell
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26
Q

2 most important factors that determine thunderstorm type…

A

Atmospheric humidity and wind shear

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27
Q

How intense are single-cell thunderstorms?

A

mild and short-lived

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28
Q

Where do single-cell thunderstorms form?

A

within mT air masses (weak wind shear)

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29
Q

When do single-cell thunderstorms typically develop?

A

Late afternoon

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30
Q

Single-cell thunderstorms typically experience a predictable sequence of….

A

growth, maturation, and dissipation

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31
Q

Multicell thunderstorms form under what wind shear?

A

moderate wind shear

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32
Q

Multicell thunderstorms form along… (where in terms of air masses)

A

Along the fronts of air masses

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33
Q

how are multiicell thunderstorms arranged?

A

In clusters or squall lines

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34
Q

What is a squall line?

A

line of multicellular thunderstorm cells that typically form along a cold front on a midlatitude cyclone

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35
Q

What is a gust front (squall line)

A

Cold surge of air at ground level

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36
Q

What is a derecho?

A

a gust front in excess of 93km/h over a 400km area

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37
Q

Where is the forward flank in a multicellular thunderstorm?

A

Hot, humid side

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38
Q

Rear flank of a multicellular thunderstorm

A

cold, dry side

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39
Q

to be classified as a severe thunderstorms they need to have 1 or more of what 3 what conditions…

A
  1. produce hail 2.54 cm in diameter
  2. a tornado
  3. wind gusts of 93km/h or greater
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40
Q

Supercell thunderstorms form over land that is…

A

humid and strong wind shear

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41
Q

What is a mesocyclone?

A

rotating column of air that is created by wind shear and updraft that may produce a tornado

42
Q

Lightning is…

A

electrical discharge produced by thunderstorms

43
Q

Thunder is…

A

acoustic shock wave produced when lightning rapidly heats and expands the air around it

44
Q

What is fulgurite?

A

lightning infused silica sand, forms glassy hollow tube

45
Q

What is the charge of earths upper atmosphere?

A

Positve

46
Q

What is the charge of earths surface?

A

Negative

47
Q

What causes lightning?

A

Updrafts. and downdrafts create a separation of electrical charges… opposite charges build up. 2 oppositely charged regions develop a connection and a bolt of lightning is born

48
Q

General current of lightning?

A

60000 - 100000 amps

~80000 amps

49
Q

How hot is lightning?

A

5 x hotter than sun, heats air to 30000C

50
Q

Percentage of lightning strikes that go from cloud to ground?

A

20%

51
Q

Who was Roy Sullivan?

A

Park ranger in Shenandoah Park, stuck by lightning 7 times.

52
Q

How do we determine distance of lightning?

A

count number of seconds until thunder occurs

- divide by 3 to get distance in Km

53
Q

what is the 30/30 rule

A
  • Lightning safety

- count to 30, if thunder occurs before you get to 30, go indoors

54
Q

Best place to be in a thunderstorm

A

Indoors

55
Q

What to do if trapped outdoors in thunderstorm?

A

Crouch low, little amount of your body touching ground

-or go in car

56
Q

Define tornado

A

Violently rotating column of air that decsends from cumulonimbus cloud

57
Q

What 3 storms do tornados form in?

A

Thunderstorms, hurricanes, cold fronts

58
Q

what is a hook echo seen on doplar?

A

Likely location of tornado but not guaranteed

59
Q

Where are the most frequent and violent tornados in North America?

A

Great Plains also known as Tornado Alley

60
Q

4 ingredients that make up Tornado Alley

A
  1. Cold Dry Air
  2. Jet Stream
  3. Warm Dry air
  4. Warm moist air
    AND LOOOW PRESSURE
61
Q

Tornados are ranked on what scale?

A

Enhanced Fujita scale (EF SCALE)

62
Q

How does the EF scale rank tornados?

A

Based on damage done to landscape

63
Q

What is a tornado watch

A

alert issued by NWS when conditions are FAVORABLE for tornado thunderstorms

64
Q

What is a tornado warning?

A

warning issued by NWS after tornado is SEEN AND CALLED IN OR SUGGESTED BY RADAR HOOK ECHO

65
Q

What is a hurricane?

A

Intense travelling cyclone of tropical and subtropical latitudes, accompanied by high winds and heavy rains

66
Q

3 Categories of Hurricans

A
  1. Hurricanes: western… North Atlantic and north east pacific
  2. Typhoons: northwest pacific… ASIA
  3. Cyclone: indian ocean
67
Q

min surface pressure needed for Hurricane

A

95 kpa

68
Q

Min wind speed needed for hurricanes

A

119km/h

69
Q

Where do hurricanes originate?

A

Warm ocean waters above 26C and between 7-15 degrees N/S

70
Q

Peak North Atlantic hurricane season

A

June-Novemeber

**PEAK ACTIVITY AUG-OCT

71
Q

Tropical Cyclones have what 3 components?

A
  1. calm eye
  2. eyewall
  3. rain bands
72
Q

Do hurricanes need wind shear?

A

NO! wind shear tears hurricanes apart!

73
Q

4 stages of a hurricane

A
  1. Tropical Disturbance
  2. Tropical Depression
  3. Tropical Storm
  4. HURRICANE!
74
Q

Hurricanes are measured on which scale?

A

Saffir-Simpson Scale

75
Q

Strongest hurricane wind speeds above

A

252 km/h

76
Q

What guides all hurricanes

A

subtropical highs

77
Q

Major cause of loss of life in a hurricane…

A

Storm Surge

78
Q

What kills people in the storm surge…

A

drowning.. 90% of deaths are related to drowning in a hurricane

79
Q

Storm Surge is caused by…

A
  1. rise in sea level by strong winds

2. low atmospheric pressure of hurricane

80
Q

Category 5 Hurricane creates what storm surge?

A

5.7m or higher

81
Q

Atlantic Hurricanes are named after

A

NAMES! 6 lists that rotate.

82
Q

What is the significance of Galveston TX hurricane in the 1900?

A

greatest loss of life in USA… 6000-12000

Cateorgy 4 storm, 4.6m surge

83
Q

What is Hurricane Katrina known for?

A

Costliest hurricane on record in USA

84
Q

Which 2 USA cities are at risk for hurricane disaster?

A

New Orlenes and Miami

85
Q

Define midlatitude cyclone

A

a low pressure system that develops in the midlatitudes

86
Q

Where do midlatitude cyclones affect

A

Midlat. region of US and Canada fall-spring

87
Q

Which are the largest storms on earth?

A

Midlatitude cyclones

88
Q

Midlatitude cyclones are composed of…

A

warm front and cold front

89
Q

What does the warm front do in a midlatitude cyclone?

A

Warm air advances on and flows over cooler and heavier air

90
Q

What does the cold front do in a midlatitude cyclone?

A

Cold air advances on relatively warm air

91
Q

Main cyclogenesis environment of midlat. cylclones

A

Downwind of mountain ranges and where warm water is located downwind of cold water or land surfaces

92
Q

How long is a lifecycle of a midlat. cyclone?

A

1-2 Weeks

93
Q

2 stages of midlat. cyclones

A

Open Wave (Separate still) or occluded (fronts combines)

94
Q

What is a nor-easter?

A

midlat. cyclone that brings blizzard conditions from mid Atlantic north to New England… similar to hurricane, not as damaging

95
Q

What are atmospheric rivers?

A

Narrow bands of moisture that stretch thousands of kms

ex. pineapple express

96
Q

What is the lake-effect snow?

A

A heavy snowfalls that results as cold air moves over large, warm bodies of water such as the Great Lakes

97
Q

Surface stations in weather forecasting

A

over 10000 land based stations provide weather observations

98
Q

What are radiosondes?

A

Weather balloons

99
Q

What are satellites

A

24 hr coverage ofor weather

100
Q

What is ensemble forecasting?

A

Several forecast models for the same area

101
Q

What is quantitative forecast?

A

specifies the future temp, precipitation amounts, rain percentage