View
- Term
- Definition
- Both Sides
Study
- All (28)
Shortcut Show
Next
Prev
Flip
ATMS 100: Midterm 2
What is a constant pressure surface? |
Constant pressure surfaces are parallel to constant height surfaces
|
How are low and high heights related to temperature below that pressure surface?
|
High heights are indicative of warm air below that pressure level
Low heights are indicative of cold air below that pressure level |
How do you identify ridges and troughs on an upper-air map? |
... |
What is pressure gradient force?What direction does it act? |
Change in pressure/distance
PGF causes the wind to blow
Tightly packed isobars --> strong PGF
Widely packed isobars--> weak PGF
Acts perpendicular to height lines toward low heights. |
What is the Coriolis force? In what direction relative to the flow does it act in the Northern Hemisphere?
|
The geographic wind blows in the Northern Hemisphere where lower pressure to its left and higher pressure to its right.
Coriolis force always acts to right of motion
Coriolis must be greater than PGF around highs. |
What is geostrophic wind? |
A theoretical horizontal wind blowing in a straight path, parallel to the isobars or contours, at a constant speed
|
What is a cyclone? |
Low pressure systems
NH: flow counter-clockwise, winds spiral inward
SH: Flow clockwise, winds spiral inward |
What is an anticyclone? |
High pressure systems
NH: Flow clockwise, winds spin outward
SH: Flow counter-clockwise, Winds spin outward |
What is gradient wind balance? |
Curved flow aloft
Lows: PGF > Coriolis
Highs: Coriolis > PGF |
What is friction? What does it do? |
Friction opposes motion, slowing the winds, and weakening the Coriolis force.
|
What is an air mass? |
A large body of air with similar temperature and moisture concentrations in the horizontal.
|
What is the center of an air mass? |
Surface high pressure systems
|
How are air masses classified? |
Classified based on moisture and temperature
First letter refers to moisture, second letter refers to temperature.
Moisture
-Continental: Dry (forms over land)
-Maritime: Moist (forms over water)
Temperature
-Tropical; Warm/Hot
-Polar: Cool/cold
-Arctic: Frigid |
What is a front? |
Boundaries between air masses of different densities
|
What are stationary fronts? |
Stationary fronts do not move
The winds in the cold air blow parallel to the front |
What are cold fronts and how do they influence weather? |
Precipitation generally showery
Brief but intense
Thunderstorms possible
Cold fronts generally extend southward or westward from a low pressure system. |
What are warm fronts and how do they influence the weather? |
Precipitation widespread, mainly north of front
Intensity is light to moderate
Mixture of precipitation types in winter
As front passes, temperatures and dewpoints increase |
How do occluded fronts influence the weather? |
Generally associated with widespread rain or snow
Temperatures may rise or drop slightly, but remain cold. |
How do occluded fronts form? |
A low pressure system strengthens, it wraps cold air around itself
|
What are drylines and how do they influence the weather? |
Separate mT air (warm/moist) front cT air (hot/dry)
|
How do you find fronts given a surface weather map? |
Temperature gradient
Dewpoint gradient |
What is a mid-latitude cyclone? |
An area of surface low pressure
|
What do mid-latitude cyclones look like on satellite imagery? |
Look like classic comma-shaped cloud
|
What is a blizzard? |
Visibility less than 1/4 a mile due to snow
Winds greater than 35MPH
Conditions must persist for 3 or more hours
NEED ALL THREE PARTS! |
What is a Nor'Easter? |
An intense mid-latitude cyclone that tracks along the northeastern coast of the United States
Can produce heavy rain and winds along coast and heavy snowfall inland |
What is the jet stream? Where is it found? |
The jet stream is a river of fast moving air in the upper atmosphere
Exists near tropopause level |
What is convergence |
An atmospheric condition that exists when the winds cause a horizontal net inflow of air into a specified region
Occurs when moving air is funneled into an area, much in the way cars converge when they enter a freeway.
|
What is divergence |
An atmospheric condition that exists when the winds cause a horizontal net outflow of air from a specified region.
|