Warm Up – Page 160

1. What type of front do you think is affecting our weather right now?

Why?

2. Copy today’s date and EQ on page 161.

A weather front is a “battle” between two different air masses that are touching.

Imagine two water balloons that are filled Imagine two water balloons that are filled with water of different temperatures. If you with water of different temperatures. If you hold one in each hand and push them hold one in each hand and push them together, the places the balloons touch is together, the places the balloons touch is thethe boundary between the two balloons. boundary between the two balloons. This would be the balloon “front.”This would be the balloon “front.”

Kinds of Fronts

• Cold Fronts

• Warm Fronts

• Stationary Fronts

• Occluded Fronts

Cold Front

• A cold front occurs when a more dense air mass pushes under a less dense air mass.

                                                                               

                                                         

                

                  

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      Notice that the colder (blue) air is pushing the other air out of the way. It is “winning the pushing battle.”

Notice the symbol for a cold front!

Notice the kinds of clouds at a cold front.

Cold front facts to know:

1. Moves quickly

3. Produces cumulus first.

2. Rapid “uplift” of air occurs due to the cold air lifting the warm air.

4. Often produces severe weather (tornadoes, hail, lightning).

5. Cooler, drier air follows.

Cold front

Drier, cooler air mass

Warm Front• A warm front occurs when a less dense air mass

rides up over a more dense air mass.

Notice the symbol for a warm front!

A warmer air mass is pushing into a cooler air mass. Because warm air is less dense, it gets pushed over the cooler air mass.

Notice the kinds of clouds at a warm front.

Facts to know about warm fronts!

1. Warm air moves over cold

2. Often begins with cirrus clouds followed by stratus.

3. Produces light to moderate rain.

4. After it passes, warmer weather.

Stationary Front• A stationary front occurs when the air masses on

either side of the front are not moving toward each other. On surface maps, a stationary front is indicated by alternating the cold/warm symbols as shown.

Sometimes is you are observant, you can see the front!

                                                                                                                                                           

                 

H stands for a high pressure air mass and L means low pressure.

Wind map

Combination map used for TV and internet

Another combination map – Can you read it?

Humidity map