Lecture 11: Mid-Latitude Cyclones Flashcards
____ is the leading edge of a cold air mass and a ____ is the leading edge of a warm air mass.
Cold front, warm front
True or False:
A day or two ahead of a cold front’s arrival, high cirrus clouds appear.
True
True or False: When a could front appears, precipitation usually is heavy, containing large droplets, and can be accompanied by hail, lightning, and thunder.
True
True or False: The aftermath of a cold front’s passage usually brings southerly winds in the Northern Hemisphere and northerly winds in the Southern Hemisphere as anticyclonic high pressure advances.
False, northerly winds in the Northern Hemisphere and southerly winds in the Southern Hemisphere as anticyclonic high pressure advances.
True or False: As a cold front approaches, the density difference between them the dense cold air mass displaces the less dense warm air mass forcing it to rise vertically
True
______ is a zone slightly ahead of a fast-advancing cold front, where wind patterns are rapidly changing and blustery and precipitation is strong.
Squall line
____ is a low pressure system that forms when a cool air mass (cP) collides with a warm, moist air mass (mT).
Midlatitude cylone
What are the four stages of a midlatitude cyclone?
Cyclogenesis
Open Stage
Occluded Stage
Dissolving Stage
Describe the cyclogenesis stage of a midlatitude cyclone
Disturbance begins to develop along polar front. Warm air near surface begins to rise, creating instability.
Describe the open stage of a midlatitude cyclone
counterclockwise flow, moist air from the south into low-pressure centre while cold air advances southeard west of centre
Describe the occluded stage of a midlatitude cycle
faster moving cold front wedges underneath slower warm front, cold air pushes warm air upwards causing precipitation
Describe the dissolving stage of a midlatitude cyclone.
dissolves when the cold air mass cuts off the warm air mass from its source of energy and moisture
A Midlatitude cyclone is also known as what?
A wave cyclone
____ are maps depict the distribution of air pressure, fronts, centres of high and low pressure and present data from climate stations.
Weather maps
What happens to temperature, moisture, wind direction, air pressure and clouds/precipitation when a warm front approaches?
Temperature: increases after warm front passes
Moisture: humidity and dew point temp increase with passage of warm front
Wind Direction: SE (E) winds before front, SW winds after front
Air Pressure: decrease in air pressure as the centre of low approaches
Clouds and Prec: gradual increase in cloud cover, precipitation near front, then partial clearing