Meteorology Ch 12

Cyclogenesis

The development and formation of a cyclone.

Explosive Cyclogenesis (Bombing)

A rapid decrease in central pressure of more than 24 mb within 24 hours.

Tropical Cyclones

Cyclones that occur between 0-30 degrees latitude and have warm cores.

Extra Tropical Cyclones

Cyclones that occur between 30 and 60 degrees latitude and have cold cores.

Hurricane Sandy

A hurricane known for having the largest tropical cyclone diameter on record.

Mid Latitude Cyclone Formation

Occurs when parallel winds go in opposite directions.

Open Wave

A stage of a cyclone where precipitation is more impactful.

Mature Stage of Cyclone

The strongest part of the cyclone.

Advanced Collusion

When a colluding front indicates that the cyclone is dying.

Source Regions for Extra Tropical Cyclones

Areas like the leeward side of the Rocky Mountains.

Alberta Clipper

A type of cyclone that affects North Dakota the most.

Colorado Low

Another type of cyclone that predominantly affects North Dakota.

Nor’easter

A storm that results from winds coming from the northeast, often bringing heavy snow.

Mid Latitude Cyclone Characteristics

Includes mT behind warm front, cP behind cold front, and mP in front of warm front.

Sleet

Precipitation that occurs in front of a warm front.

Blizzard

Heavy snowstorm conditions typically found in the wrap-around area of a cyclone.

Tight Isobars

Indicate strong pressure gradients, especially in the wrap-around area of a cyclone.

Parameters Determining Cyclone Strength

Temperature and moisture, where warming strengthens and cooling weakens a cyclone.

Low Pressure System

Characterized by surface level convergence and upper level divergence.

Surface Level Convergence < Upper Level Divergence

Indicates that the pressure of the column is decreasing, leading to cyclone strengthening.

Vertical Structure of Cyclones

Downstream of a trough shows upper level divergence and upstream shows upper level convergence.

Occluded Cyclone

The stage when a cyclone reaches maximum intensity with a closed circulation at upper levels.

Jet Streams

High-altitude winds that can strengthen cyclones.

Jet Streaks

Areas within jet streams that contribute to varied upper-level dynamics.

Four Quadrant Jet Theory

Describes the association of upper-level divergence and convergence with jet stream quadrants.

Right Entrance and Left Exit of Jet Stream

Areas associated with upper-level divergence.

Left Entrance and Right Exit of Jet Stream

Areas associated with upper-level convergence.

Cyclone Tilt

Cyclones generally tilt westward with height.

Upper Level Divergence

Occurs at the right entrance side of a jet stream.

Upper Level Convergence

Occurs at the left entrance side of a jet stream.