Mid-Latitude and Tropical Cyclones Review

Vocabulary flashcards covering the stages of development, atmospheric conditions, and associated phenomena of mid-latitude and tropical cyclones.

Mid-Latitude Cyclones

Low pressure weather systems that occur between $30^\circ$ and $60^\circ$ latitude north and south of the equator, associated with the westerlies.

Synonyms for Mid-Latitude Cyclones

Temperate cyclones, extra-tropical cyclones, frontal depressions, or wave cyclones.

Initial stage (Mid-Latitude Cyclone)

The phase where pressure differences between warm tropical air and cold polar air result in a pressure gradient around a polar front, and a disturbance forms a wave.

Mature stage (Mid-Latitude Cyclone)

The phase where air flows around a low (clockwise in the Southern Hemisphere), the polar front forms cold and warm fronts, and the area is divided into cold and warm sectors.

Occluded stage

The stage where the cold front overtakes the warm front, resulting in only cold air on the ground as lighter warm air is pushed up.

Cold Front Conditions

Weather characterized by decreasing temperature and humidity, increasing pressure in the cold sector, cumulonimbus clouds, and heavy rain or snow.

Warm Front Conditions

Weather characterized by increasing temperature and humidity, decreasing pressure, nimbostratus clouds, and soft soaking rainfall.

Cold Front Occlusion

A condition where the temperature in front of the system is higher than behind the system, and the cold front cuts into the warm front.

Warm Front Occlusion

A condition where the temperature in front of the system is lower than behind the system, and the warm front cuts into the cold front.

Tropical Cyclones

Intense low pressure storms that develop at the ITCZ outside $5^\circ$ north and south of the equator over oceans warmer than $28^\circ C$.

Coriolis Force

The force absent at the equator but present outside $5^\circ$ N and S that causes winds to spiral towards a low pressure system.

Eye of the Cyclone

A clear, calm, cloudless funnel in the center of the storm where air is warmer due to adiabatic heating.

Formative Stage (Tropical Cyclone)

The stage with very strong up draughts and intensifying low pressure, where winds start spiralling but no clear eye has formed.

Mature Stage (Tropical Cyclone)

The stage where pressure is less than $950,hPa$, wind speeds reach hurricane strength, and a clear eye is well developed.

Dissipating Stage (Tropical Cyclone)

The stage where the cyclone moves over land or cooler sub-tropical areas, leading to increased air pressure and clearing weather due to friction and less evaporation.

Storm Surge

Water pushed toward the shore by the force of winds swirling around a storm, which can increase the average water level by $4.5,m$ or more.

Flash Floods

Rapid occurring events that can begin within minutes or hours of excessive rainfall, with water reaching heights of $10,m$ or more.

Adiabatic Heating

The process responsible for making the air warmer in the clear, calm eye of a tropical cyclone as air is sucked down in the middle.

Regional Names for Tropical Cyclones

Known as Willy Willies, Typhoons, or Hurricanes depending on the location of occurrence.

Polar Front

The boundary where pressure differences between warm tropical air and cold polar air exist, leading to the development of mid-latitude cyclones.