Monday Fill out planner for the week 2.Update SN 3.Check quizzes 4.Weather Notes

Friday Turn in Precipitation WS WU: Identify each of the following fronts. HW: look over material to be tested on Tuesday and Have a good Thanksgiving StationaryCold FrontOccludedWarm

Remember that the type of ocean surface current that passes by has a direct effect on the climate and weather of the land nearby. Warm surface currents bring warmer, moister air to the surrounding areas. But cool surface currents bring cooler, drier air to the surrounding areas. The Gulf Stream The Alaska Current The California Current

Today's Goals -Use weather symbols to describe current weather on a map. -Use weather symbols to predict future weather on a map.

Cities in these areas enjoy the same, stable climate throughout the year. The ocean helps keep everything stable and unchanging. These are called maritime climates…they are located on the coast and experience small changes in temperature. Miami, New Orleans, Houston, Seattle, San Francisco, and San Diego are examples…what do you know about these climates?

However, the farther you get away from the coast, the more dramatic your weather changes throughout the year. These are called continental climates. They are located in the middle of a continent and experience BIG changes in temperature. Pittsburgh, Memphis, Minneapolis, Denver, Oklahoma City and Dallas are examples…what do you know about summer and winter in these climates? Summers can be very hot and winters can be very cold. Rainfall can vary tremendously.

Let’s start looking at the weather. On any weather forecast, you are going to see areas of Low Pressure. Low pressure areas form when warmer air begins to rise high up into the atmosphere….like a hot air balloon. As the warm air rises, it swirls counterclockwise and pulls moist, humid air up with it. L L

These low pressure areas suck air up and bring precipitation and cloudy weather wherever they go. They are usually associated with bad weather. This is some really warm and humid air. As it rises higher and higher, it starts to cool… (L in Low is for Lousy weather.) …and form clouds and precipitation. L L

On any weather forecast, you are also going to see areas of High Pressure. High pressure areas form when cooler, denser air begins to sink back down to the Earth….like a leaf blower. As the cool air sinks, it swirls clockwise and blasts cool, dry air back down on the ground. H H

These high pressure areas usually bring dry, clear, and sunny weather with them. They are usually associated with great weather. This is really dry, cool air. And no moisture means… …no clouds or rain. Just beautiful clear, sunny days! H H

Pressure systems usually deal with the amount of moisture in the air, though. Big, dramatic changes in the air temperature come from moving fronts. A front is the boundary, or dividing line between two different types of air masses. The direction the half circles are pointing tells you which direction the front is moving. Warm Fronts generally move from the Equator and bring warmer, humid air with them.

As the front moves through, it drags the associated weather with it into the area. Cold Fronts generally move from the Poles and bring cooler, drier air with them. The direction the triangles are pointing tells you which direction the front is moving.

If there is enough humidity in the air (evaporated water), you will usually experience some rain and storms as the fronts move through the area. Colder temperatures cause evaporated water in the air to condense into liquid water. This can cause rain and storms as the cold front moves in.

Sometimes when 2 air masses meet, neither one has enough pressure to push the other one out of the way. Stationary Fronts are fronts that do not move much due to warm and cold air masses that collide with equal and opposite forces. Since the 2 fronts are stationary, this weather will last for a while. It is represented with triangles on one side and circles on the other. If the original warm front had a lot of moisture in it when it collides with the cold front, what type of weather would result? Rainy Weather! The cooler temperatures in the cold front will condense the moisture in the warm front!

When a cold front overtakes a warm front it forms an Occluded front. Because the cold front overtakes the warm front there is usually warm air caught between 2 colder air masses. Occluded fronts are associated with cool temperatures and large amounts of rain and snow Occluded fronts have both circles and triangles on the front of the line since the cold front overtook the warm front.

Tuesday Update SN 2.Finish Weather Notes 3.Forecasting the Weather

Now let’s look at some special weather situations. Rain Shadows are dry areas of land that receive little rainfall on the leeward side of mountains… …while the side of the mountains closest to the ocean (windward side) are drenched in rain. The moist, humid air coming off the ocean just can’t make it over the tall mountains. So it constantly pours on the windward side and stays dry on the other. Phoenix and Seattle are good examples. What do we know about the rainfall in these places?

windward rainy leeward Dry Rain SHADOW

Now let’s look at another special weather situation. Hurricanes are massively huge low pressure systems that develop throughout the summer and fall in the warm tropical waters. As it comes on land, the system dumps a ton of rain, often flooding the area. The specific heat of the water allows it to heat up slowly and gain a lot of energy. L Hurricanes fall apart as they travel over land because it doesn’t have the warm ocean to feed it with energy and water.

So how does all of this affect us here in Frisco? During the summer and fall, warm humid air from the Gulf Of Mexico streams up from the South. But, its usually so dang hot around here that it is not cool enough for the humidity in the air to condense into rain. So we stay hot and dry…but miserably humid.

What about those crazy Frisco winters? During the spring and winter, cold fronts from the North and West provide the chilly temperatures needed to condense our humid air. So we end up with a lot more rain…and sometimes ice and snow.

Let’s Review…. What is the name of the warm water current that keeps the Southeastern United States warm and muggy throughout the year? The Gulf Stream How are Rain Shadows formed? The moist, humid air coming off the ocean just can’t make it over the tall mountains. So it constantly pours on one side and stays dry on the other.

Let’s Review…. How are Low Pressure systems different from High Pressure systems? L L H H

Let’s Review…. How are Cold Fronts different from Warm Fronts? Click here to get the current weather outlook for the United States.here

Cool Down: Describe the weather at each number.

Weather Cool & Clear Cloudy & Warm Thunderstorms Clear & Sunny

Current Weather Map