warm and occluded fronts. today cold fronts warm fronts occluded fronts

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Warm and occluded fronts

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Page 1: Warm and occluded fronts. Today Cold fronts Warm fronts Occluded fronts

Warm and occluded fronts

Page 2: Warm and occluded fronts. Today Cold fronts Warm fronts Occluded fronts

Today

• Cold fronts

• Warm fronts

• Occluded fronts

Page 3: Warm and occluded fronts. Today Cold fronts Warm fronts Occluded fronts

Idealized Cold Front

Isotherms

0C 5 10 15 20 25 30C

100 km

Frontal Zone

44 75

COLDFRONT

Page 4: Warm and occluded fronts. Today Cold fronts Warm fronts Occluded fronts

Idealized Cold Front

Cross-sectional Characteristics

Cold Air

Warm Air

Strong Lifting near thefrontal boundary can produce convective clouds.

Page 5: Warm and occluded fronts. Today Cold fronts Warm fronts Occluded fronts

Idealized Cold Front

Cold Air Warm Air

Page 6: Warm and occluded fronts. Today Cold fronts Warm fronts Occluded fronts

Idealized Cold Front

• Precipitation:

– Located on either side of the front.

– Convective, showery in nature

– If warm air is stable

• Nimbostratus, Altostratus

– If warm air is unstable

• Cumulus, Cumulonimbus, Thunderstorms

Page 7: Warm and occluded fronts. Today Cold fronts Warm fronts Occluded fronts

Idealized Cold Front

© 1999 Prentice-Hall, Inc. -- From: Aguado and Burt, Understanding Weather and Climate

Cold Air Warm Air

Surface Front

Page 8: Warm and occluded fronts. Today Cold fronts Warm fronts Occluded fronts

Idealized Warm Front

Isotherms

30C 25 20 15

100 km

Frontal Zone

83

WARMFRONT

66

Page 9: Warm and occluded fronts. Today Cold fronts Warm fronts Occluded fronts

Idealized Warm Front

• Warm Front

– A boundary that moves in such a way that the colder (more dense) air retreats and is replaced by the warmer (less dense) air.

– The warm fronts tend to have weaker temperature gradients.

Page 10: Warm and occluded fronts. Today Cold fronts Warm fronts Occluded fronts

Idealized Warm Front

Cross-sectional Characteristics

Warm Air

Cold Air

Weaker lifting near thefrontal boundary oftenproduces stratiformclouds.

NsAs

Cs Ci

Page 11: Warm and occluded fronts. Today Cold fronts Warm fronts Occluded fronts

Idealized Warm Front

• Precipitation:

– Located on the cold side of the front.

– Stratiform, more persistent in nature

– In winter, precipitation may fall as sleet or freezing rain.

Page 12: Warm and occluded fronts. Today Cold fronts Warm fronts Occluded fronts

Idealized Warm Front

© 1999 Prentice-Hall, Inc. -- From: Aguado and Burt, Understanding Weather and Climate

Page 13: Warm and occluded fronts. Today Cold fronts Warm fronts Occluded fronts

Stationary Front

• Frontal boundary that either does not move or moves very slowly.

• Stationary fronts can “wash out” as the air masses on both sides of the front become the same.

Page 14: Warm and occluded fronts. Today Cold fronts Warm fronts Occluded fronts

Occluded Fronts

• Cold fronts typically move faster than warm fronts.

• Cold fronts can catch up and “overtake” a warm front.

• Depending on the different air masses, there are two types of occlusions:

– Cold type occlusion

– Warm type occlusion

Page 15: Warm and occluded fronts. Today Cold fronts Warm fronts Occluded fronts

Cold-Type Occlusion

Cold Air

Cool Air

Warm Air

Page 16: Warm and occluded fronts. Today Cold fronts Warm fronts Occluded fronts

Warm-Type Occlusion

Cold AirCool Air

Warm Air

Page 17: Warm and occluded fronts. Today Cold fronts Warm fronts Occluded fronts

Summary

• 4 types of front

• Weather comes with fronts