Weather and Climate: Ch. 9 Flashcards
1
Q
Boundary between 2 air masses
A
Front
2
Q
In a front, one air mass is usually _________ and contains more __________
A
warmer; moisture
3
Q
Warm air gliding up and over a cold air mass
A
Overrunning
4
Q
Identification on maps:
A
- Sharp temperature change
- Shift in wind direction
- Sharp dew point change
5
Q
Front with no movement
A
Stationary Front
6
Q
Winds in a stationary front:
A
parallel but opposite direction, separating warm and cold air
7
Q
In a cold front, ___ (dominate) replaces ___
A
cP; mT
8
Q
Shape of a cold front
A
steep, nose shape
9
Q
Cold fronts move ___% faster than warm fronts
A
50
10
Q
Characteristics of a Cold Front Before Passage:
A
- Temp: Warm
- Humidity: High
- Winds: S to SW
- Pressure: Falls
- Line of thunderstorms in distance
11
Q
Characteristics of a Cold Front After Passage:
A
- Temp: drops (cold)
- Cold air advection
- Humidity: drops
- Winds: Shift SW to NW
- Pressure: Rises and skies clear
12
Q
If warm is relatively stable in a cold front what type of clouds?
A
Nimbostratus and Altostratus
13
Q
If warm air is unstable in a cold front…
A
uplift is vigorous and towering Cumulonimbus form
14
Q
What type of weather comes when warm air is unstable in a cold front?
A
strong gusty winds, hail, or tornadoes
15
Q
No two cold fronts are exactly _______
A
alike
16
Q
Some cold fronts pass with _____ in dew points, _____ wind shift
A
drop; slight
17
Q
In a warm front, ___ (dominate) air overrides ___
A
mT; cP
18
Q
In a warm front, _______ lifting produce clouds and precipitation
A
gradual
19
Q
Characteristics of a Warm Front Before Passage:
A
- Clouds lower and thicken
- Winds: E or SE
- Temps: Cool
- Humidity: Moderate to high
- Pressure: Falls
- Precipitation: steady light to moderate - may exceed 24 hours
20
Q
Winter precipitation in a warm front Before Passage:
A
snow –> sleet –> freezing rain –> rain
21
Q
What clouds lower and thicken in a warm front Before Passage?
A
- Cirrus clouds (600 miles)
- Cirrostratus
- Altostratus
- Stratus
- Nimbostratus (180 miles)
22
Q
Characteristics of a warm front after passage?
A
- Winds: S or SW
- Temps: Rise (warm) - Warm Sector
- Warm air advection
- Humidity: High
- Pressure: Rises
23
Q
Rapidly moving cold front overtakes warm front
A
Occluded Fronts
24
Q
Later stages of a storm’s life cycle
A
Occluded Front
25
Separates moist air from dry air
Dry Line
26
Dry Line has a role in ______ weather
severe
27
Synoptic-scale, low pressure system
Midlatitude Cyclone
28
Midlatitude cyclone has a diameter greater than ____ miles
600
29
Midlatitude cyclones travel _____ to _____
west to east
30
Midlatitude cyclones last few days to ...
over a week
31
Development begins along polar front
Polar Front Theory
32
Separates cold polar air from warm air
Polar Front Theory
33
Development and strengthening of a storm system
Cyclogenesis
34
Where do Midlatitude Cyclones form?
downwind of mountains and along coastlines
35
All storms tend to converge toward the ___
NE
36
Forms near TX and OK panhandle
The Panhandle Hook
37
Panhandle Hook storms travel ___ and bend and travel sharply __________
NE; northward (WI)
38
Form near CO
Colorado Lows
39
Colorado Lows storms travel ___ and then ___
SE; NE
40
When are Colorado Lows most common?
fall, winter, and spring
41
East side of Canadian Rockies in winter
Alberta Clipper
42
Alberta Clipper brings a _____, ______ storm
cold, windy
43
Alberta Clipper storms dive ____ into ________ and across Great Lakes
SE into Dakotas
44
Travel from Mid-Atlantic coast to New England
Nor'easters
45
When are Nor'easters most frequent and violent
September-April
46
Storm that form in the south yield _____ precipitation
more
47
Forms that form in the south draw...
moisture-rich air from gulf
48
Undergoes explosive development
Cyclone Bomb
49
Cyclone bombs drop at least ___ mb in ___ hours
24; 24
50
Needed for cyclones and anticyclones to maintain or intensify
Convergence and Divergence
51
For a surface LOW to strengthen (deepen), surface LOW must be ______ of ______-level low
east (right); upper-level (trough)
52
For a surface LOW to strengthen (deepen), upper level Divergence of air must be ______ than surface Convergence of air
greater
53
For a surface HIGH to strengthen (build), upper level Convergence of air must exceed...
low-level Divergence of air
54
In Convergence and Divergence, movement controlled by ________ winds at _______ (500 mb) and travel faster in ________ months
steering; 18,000'; winter
55
Zone of overunning as mT overtakes cool air
N/NE Quadrant
56
E-NE winds are in what quadrant?
N/NE Quadrant
57
In what quadrant is it cloudy and precipitation is steady, substanital
N/NE Quadrant
58
"Winds out of ____, weather a beast" is a part of the ____ Quadrant
east; N/NE
59
What are the quadrants for cyclone weather?
- N/NE Quadrant
- SE Quadrant
- SW Quadrant
- NW Quadrant
60
Mildest air in warm sector of storm is ___ Quadrant
SE
61
In which quadrant do south winds advect mT air in northward from Gulf of Mexico?
SE Quadrant
62
In the SE Quadrant, skies ______ cloudy and dew points ______
partly; high
63
The Terrible Triangle is in __ Quadrant
SE
64
There is _______ weather possible in the Terrible Triangle
severe
65
Follows cold front to south in ___ Quadrant
SW
66
The SW Quadrant has a narrow band of...
cumuliform clouds, showers, and thunderstorms (squall line)
67
In the SW Quadrant, there are _____ skies behind ____ front
clear; cold
68
Head of comma is in the ___ Quadrant
NW
69
The storm is still ________ in the NW Quadrant
developing
70
What quadrant has the lowest air temps?
NW Quadrant
71
In the NW Quadrant, strong NW winds advect __ or __ southward
cP; A
72
Nimbostratus clouds bring rain or snow in the ___ Quadrant
NW
73
In a cyclone, coldest air is located to ...
NW of low center
74
In a cyclone, warmest air is located to ...
SE of low center
75
Chicago experiences WARM SIDE of storm on track __ of a cyclone
A
76
Chicago experiences COLD SIDE of storm on track __ of a cyclone
B
77
Center of low to your _____ on Track A
north
78
Track A is a mature storm system with passage of fronts:
- Ahead of warm front (#1)
- Warm front (#2)
- Cold front (#3)
- Behind cold front (#4)
79
Center of low _____ of you on Track B
south
80
Track B has no _______ passages
frontal
81
Track B brings ______ snow or rain (__ hours or more)
steady (12 hours or more)
82
The heaviest snowfall on Track B runs parallel about ____ miles to __ of storm track
150 miles; NW
83
Track B has gusty __-__ winds shift to __ and ___
E-NE; N and NW
84
Skies clear and temps fall on Track __
B
85
Anticyclones bring _____ skies and ______ conditions
clear; calm
86
Air modifies in Anticyclones:
- NW winds ahead
- South winds as it moves away
87
Record cold in winter and heat waves in summer
Anticyclones
88
Prevent usual west to east movement systems
Cutoff Systems
89
Cutoff Systems can persist for ____
weeks
90
Example of weather extreme in a cutoff system
droughts
91
850 mb chart (1 mile):
- conditions near surface
- warm and cold air (air mass locations)
92
700 mb chart (2 miles):
Steering winds for thunderstorms
93
500 mb chart (18,000'):
Forecast direction of Midlatitude cyclone
94
When was the "Storm of the Century", most massive and disruptive MLC storm in US history
1993
95
Where was the "Storm of the Century"?
Eastern 1/3 of country
96
"Storm of the Century" produced greatest distribution of significant _____ in modern times
snow
