weather and climate

When unlike air masses meet they do not easily mix but make_____.
-transitional boundary miles wide
-lean with hight
-warm air always rises over cold air
Warm Fronts
map symbol- red half circle
Warm air is displacing cold air
-warm air gently rises up over cold air
-shallow slope 1:200
-stratiform clouds (possible cirrus clouds)
low intensity, long duration precipitation
Cold Front
map symbol- blue triangles
Cold air is displacing warm air
-Cold air forces warm air to rise violently and rapidly
-steep slope 1:40
-Cumuliform clouds
-high intensity, short duration precipitation
Stationary Front
Neither air mass displaces the other
-weather is unpredictable but can produce low intensity, long duration precpt. due to gently rising air
Extra Tropical cyclone
Sub Continental in size (1000 miles across)
-characteristic warm and cold front extends from low pressure center.
-Cold front moves faster than warm front and chases it
-Cold front overtakes warm front, lifts warm air out of contact with ground causing an occluded front
ETC movement
Four axis of movement
-air converges into the low pressur e center
-warm front rotates counter clockwise
-cold front rotates counter clockwise
-whole ETC moves from west to East with the belt of the westerlies
Occluded Front
As the cold front overtakes the warm front, the warm air is lifted out of contact with the ground causing an occluded front.
Occluded Front characteristics
Warm air is lifted out of contact with ground
-both cuniform and stratiform clouds develop
-Worst of both worlds-long duration, high intensity precp.
-Occulsion usually occurs over Eastern US and Canada
-Full occlusion is the death of the cyclone since there is no more rising air
Life Cycle of ETC
Cyclogenisis- birth of the ETC when warm and cold airmasses meet and conditions in upper atmosphere causes ETC to start spinning and move out in belt of westerly winds
maturity- ETC has well developed warm and cold fronts
Partial Occlusion- cold front partially overtakes warm front from center out
-Full inclusion- cold front completely lifts warm air out of contact with the ground of depriving the cyclone of its energy and killing it
Extra- Tropical Anticyclones
ETAC is referred to a high because it is based on a high pressure center
-migratory high pressure cell typically larger than an ETC
-ETC and ETACs alternate as they move with the westerlies
-high pressure does not produce precipitation (remember adiabatic warming of sinking air)
long term pattern over seasons of temperature and perceptation
graphic indicator of temp. and percp. for a certain place over the course of the year.

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