Practice English Speaking&Listening with: WFSTAR: Skywatching

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Staying informed on fire weather conditions and forecasts is a pretty basic concept.

But really, how easy is it? You and your crew are bombarded with information and indicators regarding your current fire environment.

I mean, you definitely need to know what your fire is doing at all times, but awareness alone is just the beginning.

Your ability to focus on what is important, and filter what is not, will allow you to interpret and convert it into something useful.

Scott Dorval is a news meteorologist in Boise, Idaho.

He will talk to you about some of the most basic

elements of sky watching and the importance of simply raising your eyes to the sky and making frequent, thoughtful observations.

When it's a hundred degrees in the summertime,

what's causing the air to rise, as the sun comes up in the morning, it heats the ground, the sun does not heat the air,

The sun heats the ground it heats solid objects. And the solid objects touching the air, the ground

is touching the air and that air then gets warm, like a radiator

warms that air and then that layer of air rises.

And then cool air comes down to replace it, and that air warms up, and it rises

and that's the mixing that occurs during the day that we talked about, when you when you talk about a fire weather forecast

mixing. The airs mixing and then it continues to rise. Rising air will then cool, as the air pressure drops,

there's no air at the top of the atmosphere, so we know as there rises

the pressures dropping and so the temperature drops. And in the clouds the the air cools,

and when it cools far enough, it hits its dew point and then a cloud forms. If you have more moisture near the ground,

you only have to take that air and bring it up a shorter distance, you'll get a cloud forming if it's extremely dry,

the temperature and dew point are very, very far apart, the humidity is very

low, and so you take this air and you have to make it rise

higher and higher and higher, as a temperature falls, that has to fall further and further, you have to make the air go higher and

higher, before you can get a cloud to form. And the reason

storms will form over the mountains first, is because it's an elevated heat source. The sun is heating the ground

in a place where it's cooler than the ambient air next to it,

and so it doesn't take the air -

it doesn't have to rise as far to get a cloud to form. That's why clouds will form right over the mountains earlier in the

day as opposed to waiting for the sun to mix that air all the way up to this point where it can mix it

right on this mountainside nearby, so.

This particular picture here is a very unstable afternoon.

You can already see the rain falling, as we're looking north into the mountains. Obviously, we're seeing a very dark cloud here.

You can see the lifting condensation level, that flat bottom to the cloud,

and you're gonna see the rain, starting in the right hand side of the picture, there at about

420 you'll see the clouds start to ripple, and that moisture just come ringing right out of the cloud, out of the thunderstorm,

we'll see it right here on the right, and

with that, you get a big burst of wind, which knocked my camera over, which is a good indicator that that was a pretty, pretty

strong storm system.

Okay, this is another indicator showing the sun is now heating the ground, and you have vertical development to the clouds,

you can see the puffiness, puffy nature to the clouds.

The sun heats the ground, the clouds, the warm air rises, makes those clouds, now the sun is going down, the heat source is

disappearing. As the heat source

disappears, the clouds just

disappear, because the only thing that's causing that moisture to condense, is the lifting of the air and the lifting of the air has

disappeared. So we might have had a fire weather forecast that said that nothing's going to happen maybe today or tomorrow, but

maybe we've got some indications that we're going to start bringing more moisture in, and then one morning you wake up

And you start to see these

low,

low clouds, they're not real big and puffy, but they have a puffy nature to them

but, that's smaller and there's little clusters of puffy clouds, and what you're seeing here is

Altocumulus Castellanos, or "Acus," that's a sign that, okay, we've got an unstable day here,

this is a day that I really need to be paying attention in the afternoon, watching for the vertical development of storms.

May not occur right over us, we may have

The Description of WFSTAR: Skywatching