Wednesday 10-30-31

Wednesday 10-30-31 • Check Weather Map Symbols • Weather Notes • Applying Weather Symbols WS

PreAP Wednesday 10-30-31 • Turn in Fast Plants Conclusions • Check Weather Map Symbols • Weather Notes • Applying Weather Symbols WS

Winter because temperatures are pretty cold, and the cold front drops very far to the South. 42o F 36o F Broken NW 3-8 mi/h 1024.6 mbar Yes Light rain -Wind is from the south -Temperatures are warmer -Pressure is lower -Wind is from the North West -Temperatures droped -Pressure is higher

45o F 38o F Obscured South 21-25 mi/h 965.4 mbar Yes Thunderstorms -Temperature at which humidity condenses into water -Occurs because the air is 100% saturated at that temperature

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

These low pressure areas suck air upand bring precipitation and cloudy weatherwherever 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.) L L …and form clouds and precipitation.

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

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… H H …no clouds or rain. Just beautiful clear, sunny days!

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. Warm Fronts generally move from the South to the North and bring warmer, humid air with them. The direction the half circles are pointing tells you which direction the front is moving.

As the front moves through, it drags the associated weather with it into the area. Cold Fronts generally move from the North to the South 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.

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… The moist, humid air coming off the ocean just can’t make it over the tall mountains. So it constantly pours on the windwardside and stays dry on the other. Phoenix and Seattle are good examples. What do we know about the rainfall in these places? …while the side of the mountains closest to the ocean (windward side) are drenched in rain.

Now let’s look at another special weather situation. L Hurricanes are massively huge low pressure systems that develop throughout the summer and fall in the warm tropical waters. The specific heat of the water allows it to heat up slowly and gain a lot of energy. As it comes on land, the system dumps a ton of rain, often flooding the area. 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? 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. The Gulf Stream

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

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

Cool Down: Describe the weather at each number.

Clear & Sunny Thunderstorms Cloudy & Warm Cool & Clear • Weather

Wednesday 10-30-31