Cold Front: FAST moving
Clouds form and there can be precipitation
After a cold front passes there will be clear skies and cooler temperatures
Front
Symbol
Air Mass Actions
Clouds Associated
w/front
CAM moves into area
where WAM is
Cold front
More dense CAM forces
WAM to rise
Happens quickly
Blue triangles in direction
CAM is moving
Resulting Weather
Quickly rising WAM –
condensation/ vertical
clouds
Cumulonimbus –
thunderstorm clouds
Cumulus – fair weather,
otherwise blue skies
(high pressure)
Precipitation and
thunderstorms – happens
quickly
Followed by clear skies,
cooler temp, low humidity
Warm Front: Slower moving may even stay for several days
Clouds and precipitation
After a warm front passes the weather is likely to be warm and humid
Front
Symbol
Air Mass Actions
WAM moves into area
where CAM is
Warm
front
Less dense WAM can’t
move CAM
WAM moves up and over
CAM
Red half-circles point in
direction WAM is moving
Eventually moves into the
area
Clouds Associated
w/front
Stratus – drizzle, mist
Nimbostratus – rain,
sleet, snow
Resulting Weather
Slow, diagonally rising
WAM – spread out clouds
of various altitudes
Extended rainy, drizzly
precipitation
Gray, cloudy skies
Followed by warmer
temps, higher humidity
Stationary Front: Air Mass “Stand off”
Cold and Warm fronts meet but neither one can move the other. Water vapor in the warm air condenses into rain, snow,
fog or clouds. If it is stalled in an area it may bring days of clouds and precipitation.
Front
Symbol
Air Mass Actions
CAM and WAM meet in
an area
Stationary
front
Blue triangles and red
circles on opposite sides
of line
“battle” back and forth in
a “standoff” because
neither can move the
other
Clouds Associated
w/front
Nimbostratus, stratus,
fog
Resulting Weather
Low clouds, prolonged
light/moderate
precipitation for possibly
several days until the
standoff ends
Occluded Front: Warm air mass is cut off from the ground (stuck between two cooler air masses.
The denser cool air masses move underneath the less dense warm air mass and push the warm air mass upward.
The temperature near the ground gets cooler. As the warm air cools and its water vapor condenses the weather may turn
cloudy and rain or snow may fall.
Front
Occluded
front
Symbol
Can also be with blue
triangles and red circles
On same side of line
Air Mass Actions
Quickly moving cold front
moves towards a warm
front and the WAM gets
sandwiched between two
CAMs! Less dense WAM
rises.
Clouds Associated
w/front
Nimbostratus – rain, snow
Cumulonimbus thunderstorms
Resulting Weather
Moderate/heavy precip.
due to quickly rising
WAM, can be prolonged
Followed by cooler
temps/low humidity