Atoc 1050 chapter 8

stationary front

-not moving(neither toward cold air mass or warm air mass) parallel to the line of the front -clear or cloudy skies w possible light rain -switch off triangle and circle

polar front theory steps

1. stationary front, separates cold polar air from warm sub-tropical air 2. frontal wave, initial kink that forms on the polar front 3. open wave, fully developed cyclone 4. mature, pressure drops, winds increase, and the cold front inches closer to the warm front 5. advanced occlusion, cold front has caught up to the warm front leaving cold air at the surface 6. dissipation, without a surface temperature gradient, the cyclone loses energy and gradually dies out

mid-latitude cyclone

A cyclone that forms in the middle latitudes (florida to alaska) at the polar front (large temp gradient), responsible for most of the weather there

What type of airmass forms over Mexico in the summer?

Ct

upper level divergence

E side of an upper level TROUGH or W side of an upper level RIDGE

What would happen to a surface low pressure if it were located to the west of an upper level trough?

The surface pressure would increase, causing the low pressure system to weaken

maritime tropical

WARM/hot MOIST, UNstable gulf of Mexico, sub tropical pacific PRECIPITATION

Warm Front

Warm, moist air replaces cold, dry air In front of the warm front, surface winds are light and variable, temperatures are cold, and high cirrus clouds are overhead snow changes to rain The winds become brisk and out of the southeast and atmospheric pressure slowly decreases, fog possible -After the front has passed, the temperatures will INC, the dew point will increase, the winds shift from SE to S or SW, and the atmospheric pressure stops falling. The precipitation stops and most of the clouds clear (some stratocumulus will remain)

a warm front is associated with ..?

a broad region of light precipitation

squall line

a line of active showers and thunderstorms that develop parallel to and often ahead of an advancing cold fron

Polar-Front Theory (Norwegian Cyclone Model)

a theory that explains the life cycle of mid-latitude cyclones and their associated front

in order for a surface high pressure to remain a high pressure, upper level convergence must ____ mass to the column of air

add

Air mass modification

air mass modified by the surface below (temp, moisture, stability)

definition of an air mass

an immense body of air. The air is characterized by homogeneous physical properties at any given altitude.

lee-side low (CO)

as westerly winds blow over a mountain range, the air expands vertically on the downwind (lee) side, which can help intensify any pre-existing areas of low pressure

front

boundary surfaces that separate air masses of different DENSITIES

___________ is/are expected in front of a warm front and ___________ is/are expected in front of a cold front.

broad, light showers; narrow band of heavy precipitation.

continental polar

cold dry stable

Occluded front cold occluded front warm occluded front

cold front catches up to a warm front The air behind the cold front is colder than the air ahead of the warm front The air behind the cold front is not as cold as the the air ahead of the warm front

backdoor cold fronts

cold fronts that move in the from the E, or NE (regular cold fronts tend to move toward the south, southeast, or east). Backdoor cold front usually move OUT of Canada and into the northeastern United States

Maritime polar

cold, MOIST, UNstable N pacific, N Atlantic RAIN/SNOW

cold front

cold, dry air replaces warm, moist air(forces warm air upwards) moves fast -Large changes in temperature over a short distance -Change in moisture content of air -Shift in wind direction -LOW pressure regions -Cloud and precipitation patterns THUNDERSTORMS< HEAVY RAIN, STRONG WINDS -wedges under warm air --> warm air move up --> creates clouds -upper level westerly winds create big clouds -as it passes, temp drops, winds shift from SW to NW, precipitation stops, PRESSURE RISES - a narrow band of precipitation along the cold front with potential severe thunderstorms directly along the front

In order for surface high pressure system to stay a surface high pressure system, it must be located under a region of upper-level ____________, which occurs to the ____________ of an upper-level trough

convergence, west

nor'easter

east coast mid-latitude cyclone that develops or intensifies off the east coast of North America in the fall, winter, or spring. They produce strong winds and heavy rain, snow, and sleet

t/f clouds/precipitation should be expected after a warm front passes over a location.

false

during a warm front, the dew point ______, the temp _______ the winds shift from _____ to ______ and the pressure stops falling.

increases, increases, southeast, southwest.

source regions for an air mass

must be extensive/physically uniform must be a region dominated by stationary or slow moving anticyclones with calm winds

Air Mass classification

named for latitude and the surface of the source region. latitude = 1.arctic, 2.polar, 3.tropical surface= 1.maritime, 2.continental

which way does a stationary front move?

no where

What occurs when a warm front catches up to a cold front?It results in cold air near the surface and warm air aloft.

occluded front

upper level convergence

occurs on the W side of an upper level TROUGH or E side of an upper level RIDGE

If the upper-level geopotential height contours have a constant distance between the contours, the winds around the _____________ will be faster than the winds around the __________

ridge, trough

the winds will be faster in the region of an upper-level ---- than in a region of an upper-level ___

ridge, trough

A typical mid latitude cyclone begins with a ____ and ends with an ______

stationary front, occluded front

low pressure at the surface is associated with

surface convergence

high pressure at the surface is assosiated with _____

surface divergence

convergence aloft is necessary in order to maintain ________

surface high pressure

What would happen to a surface high pressure system if it were located to the east of an upper level trough?

surface pressure will decrease, causing the high pressure system to weaken.

overrunning

the rising of warm air over cold

continental arctic (ca)

very very cold very dry stable N canada and alaska lake effect snow WINTER ONLY

warm sector

warm air mass located between the cold and warm fronts

continental tropical

warm, hot DRY n mexico clear skies, hot temp, no precipitation

Areas of upper level convergence occur to the _____________ of an upper level trough. In areas of upper level convergence mass is _____________ to/from the column of air

west, added

convergence

winds cause a horizontal net inflow of air into a specified region. adds mass to a column of air caused by:wind direction, change in wind speed (fast approach slower)

divergence

winds cause a horizontal net outflow of air into a specified region removes mass from a column of air slower winds approach faster winds