exam 4 Flashcards
(137 cards)
1
Q
air masses are characterized by
A
homogeneous physical properties
-temperature & humidity
2
Q
A or cA
A
continental arctic
3
Q
cP
A
continental polar
4
Q
mP
A
maritime polar
5
Q
mT
A
maritime tropical
6
Q
cT
A
continental tropical
7
Q
what air mass is best described by the following:
canada, not as cold as arctic, lake erie modifies temperature upward
A
continental polar (cP)
8
Q
what air mass is best described by the following:
gulf of mexico, austin, houston, new orleans, ingredient in thunderstorms
A
maritime tropical (mT)
9
Q
what air mass is best described by the following:
think arctic circle, barrow, alaska, only reached austin a couple of times
A
continental arctic (A or cA)
10
Q
c =
A
land
11
Q
m =
A
water
12
Q
T =
A
warm
13
Q
P =
A
cool
14
Q
A =
A
very cool
15
Q
what air mass is best described by the following:
northern desert in mexico, part of new mexico, and arizona; hot and dry
A
continental tropical (cT)
16
Q
dry air has a (higher/lower) molecular weight
A
higher
17
Q
fronts are found
A
in troughs of low pressure
**surface convergence and upper level divergence
18
Q
what is cyclogenesis
A
low pressure developing at the surface
19
Q
what causes cyclogenesis
A
increased surface convergence and upper level divergence (low pressure)
20
Q
what is a front
A
a boundary between air mass
21
Q
frontolysis
A
a weakened or dying front
22
Q
frontogenesis
A
the birth or growth of a new front
23
Q
overrunning
A
when less dense air mass runs up over a heavier air mass (frizzing drizzle, lots of clouds)
24
Q
cold front
A
4 - 5 mph
- when cold air ACTIVELY advances into a region formerly occupied by warmer air
- steeper slope
- the most dynamic weather comes from the cold frontal lift
25
a cold front is shown by the color _____ and a line of ________ pointing in the direction that ________________
blue ; triangles ; the front is moving
26
warm front
- when the surface position of a front moves such that warmer air occupies territory formerly occupied by colder air
- more gentle slope
27
a warm front is shown by the color _____ and a line of _________pointing in the way that ____________
red ; semicircles ; the front will move
28
stationary front
- when little forward movement of either air mass, usually upper level winds are parallel to the surface frontal boundary
- causes the floods in TX
29
a stationary front is shown by a line of ___________
ALTERNATING triangles and semicircles
30
occluded front
- when a cold front overtakes a warm front in the vicinity of a surface low
- more common over northern US
31
an occluded front is shown by a line of _____________
triangles and semicircles
| all on one side of the line, unlike stationary fronts where the triangles and semicircles are alternating
32
what do dry lines do
separate two air masses - boundary between cT (hot, dry air) and mT (warm, moist air)
33
true/false: dry lines are a type of front
FALSE ; dry lines are not technically a front
34
the molecular weight of cT air is __________(heavier/lighter) than that of the mT air.....what does this mean?
heavier ; when it charges east a dry line lift occurs which can cause thunderstorms
35
define weather forecasting
predicting how the state of the atmosphere will change with time
36
what resources do we use to "piece together the puzzle" of weather forecasting?
- satellite
- doppler radar
- rawinsondes
- aircraft data
- lightning data
- buoy data
- weather charts/maps
- numerical weather predictions/comp model
- citizen weather observations
- surface aviation weather observations
- storm spotters/chasers
- looking outside
37
what air mass is best described by the following:
northern pacific/atlantic, foggy, rainy, chilly
*think Seattle
maritime polar (mP)
38
remember that air masses ________ as they move
modify
**meaning they can start off as one type (ex: cT) and modify into another as it travels (ex: mT)
39
severe weather and thunderstorms are associated most with which type of front
cold front
**need dynamic lift
40
define overrunning
less dense air spreading over/occupying more dense air
41
how does warmer air remover colder air
from the top..."eating" its way down
42
what type of front are floods associated with
stationary front
43
what type of front are clouds and fog associated with
occluded front
44
to be able to forecast the weather, what must be known
the current weather information over a large area
45
ASOS/AWOS cannot observe
- hail
- tornadoes
- sleet
- snow depth
46
what is one of the most reflective hydrometers
wet hail
47
humans augment what weather observations
- hail
- tornadoes
- sleet
- snow depth
48
what is the cone of silence
a single sight radar ; when a storm is near or over the radar site, data is unavailable and shows up as this black hole
***NOT SURE ABOUT THIS
49
what color representations on a radar are more reflective/less reflective
less reflective = green
| more reflective = red
50
ASOS/AWOS can observe
- temperature
- pressure
- speed
51
how often are rawinsondes released
twice a day at hundred of locations worldwide ( 6-7 am & 6-7pm CST)
52
what do rawinsondes measure with ascension
- temperature
- humidity
- atmospheric pressure
- wind speed/direction
53
what is the average flight of a rawinsonde
60 - 90 minutes
54
how high do rawinsondes travel
as high as 100,00 ft (15 - 20 miles)
55
what are METARS
coded aviation (surface) weather observations that are transmitted globally >hourly ; it is a description of the meteorological elements observed at an airport at a specific time
56
what does WMO stand for
World Meteorological Organization
*it is a UN specialized agency
57
what is the WMO responsible for
the international exchanges of weather data and certifying that the observation process DOES NOT vary between nation since all weather observations must be comparable
58
where do people get their weather forecasts
- radio
- tv
- internet
- newspapers
- AMS/NWA
59
what does it take to be a part of AMS
AMS certified broadcast meteorologist have to pass a test ; joining the AMS/NWA is voluntary because we do not/rarely license meteorologists in the US
60
who issues weather watches/advisories/warnings
the National Weather Service (government)
**this is the SOLE source to issue these
61
which is described below: watch, advisory, or warning?
type of weather specified is imminent or is occurring and is a public inconvenience (smaller to larger geographic area)
advisory
62
which is described below: watch, advisory, or warning?
type of weather specified is imminent or is occurring and is an immediate threat to life and/or property (generally smaller geographic area)
warning
63
which is described below: watch, advisory, or warning?
atmospheric conditions are favorable for the type of weather specified (generally larger geographic area)
watch
64
time span of weather watches
longer time span: 4 - 6 hours up to 24 - 48 hours
65
time span of weather advisory
6 - 24 hours
66
time span of weather warning
.5 - 1 hour
67
what are the different methods of forecasting
- persistence forecasting
- steady state/trend forecasting
- analogue method forecasting
- ensemble forecasting
- climatological forecasting
- "gut" forecasting
68
what type of forecasting method is best described by the following:
looking at similar systems from the past
analogue method forecasting
69
what type of forecasting method is best described by the following:
looking at movement of system
steady state/trend forecasting
70
what type of forecasting method is best described by the following:
tied to numerical weather prediction; several members are run to collect data and test accuracy of model
ensemble forecasting
71
what type of forecasting method is best described by the following:
basing forecast on climate/previous trends of that location and season
climatological forecasting
72
what type of forecasting method is best described by the following:
most valuable in short term, use when pattern is stable
persistence forecasting
73
what type of forecasting method is best described by the following:
go with and make decisions based on your experience/instinct
"gut" forecasting
74
weather forecasting is a ___________ science
non-perfect
75
what method of weather forecasting should be used
all of them! don't just look at one, use a combination
76
what does NWP stand for
Numerical Weather Prediction
77
what is NWP
computer atmospheric models made through programs
78
how often are NWP models run
1-4 times/day
79
what are some problems with the NWP system
- if bad data in, then bad data out
- model make certain assumptions therefore have certain biases
- data sparse areas of the world
- cannot adequately interpret many of the factors that influence surface weather
- small disturbances/errors tend to be amplified with time
80
what does POP forecasting stand for
probability of precipitation
81
true/false: POP forecasting is very misunderstood
true
82
how do we arrive at forecast POP
(forecaster certainty) x (areal coverage expected)
EX: 50% x 20% = 1000 or 10% POP
**it means there's a 10% chance that it will rain AT A GIVEN LOCATION
it does not mean that it will be raining 10% of the time or 10% of the area
83
what is the short term forecast accuracy
80-90% (today/tonight)
84
what is the medium term forecast accuracy
over 80% (2-3 days out)
85
what is the monthly or seasonal outlook accuracy
much lower (30-90 days out)
86
what is the longer range forecast accuracy
70% (4-8 days out)
87
what percent of thunderstorms worldwide are classified as severe
less than 5%
88
true/false: straight line winds can cause more damage than tornadoes
true ; straight line winds diverge whereas the winds of tornadoes converge
89
what are the basic requirements for a thunderstorm
- lift
- instability
- moisture
90
how long to most thunderstorms last
about an hour
91
how are thunderstorms brought to an end
the down draft (cold, more dense air) cuts off the updraft and the storm commits atmospheric "suicide"
92
true/false: severe thunderstorms do not last as long as air mass thunderstorms
false ; severe thunderstorms are longer lasting because of an established/well developed wind structure (2 hours longer)
93
where do most severe thunderstorms occur
middle latitudes along cold fronts/dry lines
**cP/mP/mT/cT boundaries
94
what are the criteria for a US severe thunderstorm
- presence of a tornado
- 1 inch or larger diameter hail (@ surface)
- convective wind gusts of 50 knots/58mph
**this is an AND/OR list; only one criteria must be met for it to be considered severe
95
true/false: the presence of an initial tropospheric temperature inversion contributes to thunderstorm development
true
96
define squall lines
a line of thunderstorms
97
what is something you should always remember to look for in a squall line
always watch for the storm at the end of the line
98
what determines the severity of the individual thunderstorms in a squall line
the density of the storms along the line
99
define super cells
long lasting thunderstorms that develop a strong, internal wind structure and that control their atmospheric environment
100
true/false: super cells are always severe
true
101
define mesocyclones
a rotating updraft, usually 3 - 7 miles, within an intense cumulonimbus cloud/severe thunderstorm
102
what percent of mesocyclones produce tornadoes
less than 20%
103
what is a mesoscale convective complex/system
a number of individual thunderstorms that grow in size and arrange and organize into a long lasting convective complex
104
where are mesoscale convective systems commonly found
USA plains and into Mississippi Valley
105
how much larger can mesoscale convective systems be than average air mass thunderstorms
as much as 1000x
106
what does derecho mean
"straight ahead" or "direct"
107
what is a derecho
a widespread and usually fast moving convective wind storm
108
how severe is the reach and damage of a derecho
can produce damaging wind over areas hundreds of miles long and more than 100 miles across
109
true/false: thunderstorms are bad for the environment
false; thunderstorms are good for the environment because they help keep the Earth in electrical balance; they also serve as a great way for the atmosphere to release energy
110
what are the 4 different types of thunderstorms
- single cells
- multicell clusters
- multicell lines
- supercells
111
what are the stages of thunderstorm developement
- cumulus (updrafts dominate)
- mature (updrafts/downdrafts coexist)
- dissipating (downdrafts dominate)
112
lightning won't develop until _____________ develop
downdrafts
113
at any given moment, how many individual thunderstorms are in progress worldwide
2000
114
of the 2000 individual thunderstorms in progress worldwide, what percent are severe or non-severe
over 95% non-severe ; less than 5% severe
115
what are the differences in hail size between severe and non severe thunderstorms
non-severe : hail less than 1" in diameter
| severe: hail equal or greater than 1"
116
what are the differences in formation location between severe and non-severe thunderstorms
non-severe : found WITHIN mT airmass
| severe : found ON boundaries of mT airmass
117
hail size (and thunderstorm severity) is entirely dependent on _____________
thunderstorm updraft and downdraft speed
118
largest hail often falls ________ (NW, NE, SW, SE) of tornadoes
NE
119
what is the number one weather killer in the US
summer heat
120
true/false: flash floods are one of the top weather killers in the US
true ; general public does not understand the power of moving water
**south central texas is considered the flash flood capital of the US
121
what are straight line thunderstorm winds
strong downdraft winds from thunderstorms with a divergent wind pattern
**referred to in general as downbursts
122
where are GOES satellites east and west located
GOES west is at 135 W longitude
| GOES east is at 75 W longitude
123
what are the three different satellite image types
visible, infrared, and water vapor
124
what does the visible satellite image type display
shows what the sun light up, cannot see at night
125
what does the infrared satellite image type display
hotter colors denote colder cloudtops, 24 hrs a day
126
what does the water vapor satellite image type display
mid and upper level atmospheric moisture
127
reflectivity vs. velocity data
reflectivity will show levels of precipitation
velocity will show where it's moving
128
what is clear air mode
when there is high certainty of no precipitation, satellites can enter this mode and not do as much work
129
what is dual pol
horizontal and vertical measurements/waves, this crossection allows us to capture both size and shape of hydrometers
130
ASOS stands for
automated surface observing system
131
AWOS stands for
automated weather observing system
132
an example of an airport that uses human augmentation
austin bergstrom
133
an example of an airport that does not use human augmentation
camp mabry
134
what are the most common lightning types
cloud to cloud & intracloud
135
a bolt of lightning is about the diameter of...
a pencil
136
within the lightning bolt, it is about ___ times the temperature of _______________
5 times the temperature of the outer surface of the sun
137
what about tornadoes kills most people
the flying debris
