References: -FTGU, pages 140 to 145 -Transport Canada Study and Reference Guide Glider Pilot -Air Command Weather Manual, Chapter 7 and 8 : References: -FTGU, pages 140 to 145 -Transport Canada Study and Reference Guide Glider Pilot -Air Command Weather Manual, Chapter 7 and 8 40 Minutes 5.09 Fronts and Frontal Weather BC Online Ground School: Meteorology
Slide 2 : 1. What type of weather is associated with:
a. A cold air mass:
Good visibility, cumulus clouds, turbulence, showers
b. A warm air mass:
Poor visibility, stratus clouds, smooth air, steady precipitation
2. What is an air mass?
A mass with uniform properties of temperature and moisture
3. Name some air masses that are over North America.
Continental Arctic (cA), Maritime Polar (mP), Continental Polar (cP), Maritime Tropical (mT)
Slide 3 : MTPs:
Front - Definition
Front Formation
Warm Front
Cold Front
Fronts as seen on maps
Stationary Fronts
Occluded Fronts
Upper Fronts
Slide 4 : Definition:
FTGU: Transition zone between two air masses
What’s happening at a front?
Large change of temperature within a relatively short distance of 50-100 miles in the zone between air masses
The interaction zone between the air masses is responsible for weather changes Front
Slide 5 : Require:
a cold air mass and a warm air mass are lying adjacent
mixing action
Slide 6 : A warm front is the retreating edge of a cold air mass
Warm air advances and overruns retreating cold air
Warm air rises since it is less dense than cold air
Usually moves slower than a cold front
Long gentle frontal slope. Simulation
http://www.phschool.com/atschool/phsciexp/active_art/weather_fronts/
Slide 7 : Warm front weather
Warm air mass pushes moisture up the slope, causing cloud and precipitation
Overrunning, moisture content and stability of warm air determines severity of weather
If the warm air is unstable, thunderstorms may be embedded
Slide 8 :
Slide 9 : Indication of Approaching Warm Front:
CCANS
Cirrus
Cirrostratus
Altostratus
Nimbostratus
Stratus
Slide 10 : A cold front is the leading edge of an advancing cold air mass
Cold air undercuts the warm air
Rising warm air expands and cools
Cumulus cloud
Slide 11 : Slope can be very steep
Weather severity determined by moisture content and stability of the warm air mass Simulation
http://www.phschool.com/atschool/phsciexp/active_art/weather_fronts/
Slide 12 :
Slide 13 : Temperature
May drop sharply after front passes
Usually drops gradually as air behind is warmed by the ground
Pressure
Decrease, followed by a marked rise after frontal passage
Slide 14 : Red = Warm
Blue = Cold
Slide 15 : SUMMARY 300nm to 600nm
Slide 16 : Sometimes an air mass is neither advancing nor retreating
Results in Stationary Front
After a few days, the front may dissipate or start moving Simulation
http://www.phschool.com/atschool/phsciexp/active_art/weather_fronts/
Slide 17 : Occluded front
Cold air moves faster than warm air therefore cold front may catch up to warm front
Cold front undercuts and lifts existing warm front Simulation
http://www.phschool.com/atschool/phsciexp/active_art/weather_fronts/
Slide 18 : Results is a trough of warm air aloft » TROWAL
TROWAL weather varies
Combination of cold and warm frontal conditions
Slide 19 : Upper Cold Front: Cold front crosses valley where there is colder air that cannot be undercut
Front is lifted
Upper Warm Front: Warm front crosses cold air trapped on the ground
Very shallow frontal edge, followed by a sudden steepening of the frontal slope
Slide 20 : Another type of Upper Warm Front:
Occurs on a hot day
Cold air is heated at the until it is no longer considered cold
Results in Upper Warm front.
Slide 21 : 1. Label where the cold front and where the warm front is.
2. Label what clouds are associated with the fronts
3. Draw an arrow to show which direction the front is moving
Slide 22 : What weather is associated with a cold front?
What weather is associated with a warm front?
What types of front are the following?
Slide 23 :