Mid-Latitude Cyclones: Stages, Development, and Key Concepts

What is a mid-latitude cyclone?

A low-pressure system that forms along the polar front in middle latitudes.

What is the polar front?

Boundary separating cold polar air from warmer mid-latitude air.

What theory explains mid-latitude cyclone development?

Polar Front Theory.

What characterizes the initial stage of a mid-latitude cyclone?

Cold air to the north, warm air to the south, with winds flowing parallel in opposite directions.

What begins to develop in the initial stage?

Cyclonic wind shear.

What forms during the frontal wave stage?

A wave or kink along the front.

What develops at the frontal wave?

A low-pressure center with a cold front and warm front.

Where is the lowest pressure in the frontal wave stage?

At the junction of the warm and cold fronts.

What is overrunning?

Warm air rising over cold air ahead of a warm front.

What happens to pressure during the open wave stage?

Central pressure decreases.

How do winds behave in the open wave stage?

Counterclockwise and inward toward the low.

Where does precipitation occur in the open wave stage?

Wide band ahead of warm front and narrow band along cold front.

What is the warm sector?

Region between the warm and cold fronts.

What happens to wind speed in the mature stage?

Winds become strongest.

What happens to the cold front in the mature stage?

It catches up to the warm front.

What happens to the warm sector in the mature stage?

It becomes squeezed.

What is occlusion?

When the cold front overtakes the warm front.

What is the triple point?

The point where the cold, warm, and occluded fronts meet.

Where is the most intense weather during occlusion?

Near the occluded front and triple point.

Why does a cyclone weaken after occlusion?

Cold air surrounds the system, cutting off warm air energy.

What happens to the storm during dissipation?

It gradually weakens and dies.

What is convergence?

Air flowing together at the surface.

What does convergence cause?

Rising air and storm development.

What is divergence aloft?

Air spreading out above the system.

Why is divergence aloft important?

It removes air from above, lowering pressure and strengthening the cyclone.

What condition strengthens a cyclone?

Divergence aloft greater than surface convergence.

What causes a cyclone to weaken?

When convergence exceeds divergence (system 'fills').

What does the jet stream do to a cyclone?

Removes air aloft, strengthens the storm, and steers it.

In what direction are mid-latitude cyclones typically steered?

Northeast.

What provides energy for mid-latitude cyclones?

Temperature differences between air masses and latent heat release.

Where is widespread precipitation found?

Ahead of the warm front.

Where is intense, narrow precipitation found?

Along the cold front.

What is cyclogenesis?

Formation and development of a cyclone.

What is a lee-side low?

A cyclone that forms on the downwind side of mountains.

What are common cyclone formation regions?

Gulf of Mexico, East Coast (Cape Hatteras), and east of the Rockies.