Download Frontal Weather - Smyth County Schools

Frontal Weather
By
Diana L. Duckworth
Rustburg High School
Campbell County, VA
Fronts are the boundaries
between air masses.
• Cold Front – cold, dense air pushes out
warm air; polar air mass moves south.
• Warm Front – warm, low density air drags
cold air out; tropical air mass moves north.
• Stationary Front – air masses stop moving
• Occluded Front – cold front overtakes a
warm front and scoops warm air up – front
is present only in upper atmosphere.
Cold Front Weather
Warm Air
Cold Air
Short, violent storms –
Thunder & Lightning
Tornadoes
High winds, hail
Heavy downpours
Sharp drop in air pressure, followed by clearing.
Vertical development clouds – cumulus & cumulonimbus
Warm Front Weather
Warm Air
cirrus
Cirrocumulus, cirrostratus
Altocumulus
Altostratus
Stratus; nimbostratus
Cold Air
Pressure gradually decreases then rises.
Slow moving, covers 100’s of miles.
Clouds gradually decrease in altitude; horizontal development.
Rain or snow are steady; weather is not violent.
Front Symbols
1
2
1. Cold Front
2. Warm Front
3
4
3. Stationary Front
4. Occluded Front
Triangles or hemispheres point in the direction its moving.
Figure from Project Datastreme
Weather in Pressure Systems
• High Pressure (Anticyclone)
– Clear Sky; Light Wind
– Clockwise circulation,
– Sinking air
• Low Pressure (Cyclones) - STORMS
– Overcast; Precipitation
– Counterclockwise circulation
– rising air