1. Predicting Weather

2. Large-Scale Weather Systems
Front
narrow region separating two air masses of different densities.
Density differences are caused by differences in temperature, pressure, and humidity.
Types of Fronts
1. Cold
2. Warm
3. Stationary
4. Occluded
Stable Air
Resistant to rising, fair weather

3. Two Types of Fronts
1. Warm Front

4. As the warm front moves in rain or snow begin
they produce precipitation over large areas for an extended time

5. Warm Front
Forms when warm air move into an area formerly covered by cooler air.
On a map a warm front is shown with a red line with semicircles pointing toward the cooler air.
extensive cloudiness and precipitation
1st sign of a warm front is cirrus clouds, followed by stratus and nimbus

6. 2. cold front

7. COLD FRONT
Forms when cold, dense air moves into a region occupied by warmer air
On a map a cold front is shown with a blue line edged with blue triangles that point toward the warm air mass
Towering clouds are a sign of a cold front produce showers, and thunderstorms

8. Associated with more violent weather
Due to rate of movement and steepness of slope
Forceful uplifting leads to heavy rain, down pours, and gusty winds

9. 3. Stationary Front The front becomes parallel to the jet stream.
moves very slow
Show with blue triangles on one side and red semicircles on the other side
Clouds and steady rain or snow for several days

10. 4. Occluded Front When two cold fronts force out a warm front
Weather is very complex and unpredictable
Precipitation is common on both sides of an occluded front

11. Cyclones AntiCyclones Centers of low pressure that travel west to east
Travel in a counterclockwise direction
AntiCyclones
Centers of high pressure
Travel in a clockwise direction