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How does low barometric pressure increase storm/wind activity?

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MoonRiver Donating Member (1000+ posts) Send PM | Profile | Ignore Tue Sep-20-05 03:04 PM
Original message
How does low barometric pressure increase storm/wind activity?
Does it have to do with creating some kind of atmospheric vaccuum? :shrug:
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DoYouEverWonder Donating Member (1000+ posts) Send PM | Profile | Ignore Tue Sep-20-05 03:05 PM
Response to Original message
1. The lower the pressure
the bigger the storm.

If the pressure continues to drop the storm is getting stronger, if the pressure goes up that means the storm is weakening.

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MoonRiver Donating Member (1000+ posts) Send PM | Profile | Ignore Tue Sep-20-05 03:07 PM
Response to Reply #1
3. I know all that!
But WHY does barometric pressure result in stronger storms? Inquiring minds (or at least mine :D) want to know!
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WolverineDG Donating Member (1000+ posts) Send PM | Profile | Ignore Tue Sep-20-05 03:19 PM
Response to Reply #3
9. less resistance
barometric pressure of the surrounding areas also indicates where a hurricane may go. if there's a high pressure dome over louisiana, then texas gets it & vice versa....the path of least resistance.

dg
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Ready4Change Donating Member (1000+ posts) Send PM | Profile | Ignore Tue Sep-20-05 03:23 PM
Response to Reply #3
12. Air tries to flow from High pressure to Low.
The air inside an inflated balloon is under high pressure. When you release that air it rushes out into the surrounding lower pressure air, until the air remaining inside the balloon is at the same pressure as the outside air.

The same thing happens in the Earths atmosphere, except there is no balloon containing that air. Instead, sheer distance separates and divides zones. But still, High pressure air tries to rush into Low pressure areas, creating wind.

The larger the pressure difference between the High and Low zones, the higher the winds will be. Hurricanes have very low pressures, so their winds get very high.
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MoonRiver Donating Member (1000+ posts) Send PM | Profile | Ignore Tue Sep-20-05 03:31 PM
Response to Reply #12
13. OK, I can definitely visualize and extrapolate to a hurricane, the balloon
analogy. Sorta, I think. I'm a social scientist, and this weather science is still a little foggy to me.
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Ready4Change Donating Member (1000+ posts) Send PM | Profile | Ignore Tue Sep-20-05 03:35 PM
Response to Reply #13
16. I'm barely ahead.
I took a meteorology (weather) course in college, and, being a pilot, have paid a LOT of attention to air flows and weather systems.

I'm sure you know things regarding demographics that would boggle me, too.

:)
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MoonRiver Donating Member (1000+ posts) Send PM | Profile | Ignore Tue Sep-20-05 03:41 PM
Response to Reply #16
20. Well, I'm a social scientist in the strictly applied sense.
I don't do research, but have had my share of statistics courses (please God NO MORE). I think weather is fascinating. If I had to do it again, and had better math skills, that would be an area I'd love to major in.
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Ready4Change Donating Member (1000+ posts) Send PM | Profile | Ignore Tue Sep-20-05 03:52 PM
Response to Reply #20
21. Weather 101 requires very little math.
It's mostly conceptual. You'd likely find it just the ticket.

And the only thing I learned from my statistics course was to not trust statistics. ;)
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MoonRiver Donating Member (1000+ posts) Send PM | Profile | Ignore Tue Sep-20-05 07:09 PM
Response to Reply #21
23. Well, I did take Astronomy for non-science majors. I loved it!
I might do just fine in Weather 101. As for statistics, I certainly have my issues with the field.
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maine_raptor Donating Member (1000+ posts) Send PM | Profile | Ignore Tue Sep-20-05 03:36 PM
Response to Reply #13
17. You can perform a visual experiment
fill the bathtub with a small amount of water. Add in a few drops of food color. Do not stir or mix the food color. Now open the drain and watch how the dye moves with the water into the drain.

Air works the same way. It behaves much like water (fluid dynamics).
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phantom power Donating Member (1000+ posts) Send PM | Profile | Ignore Tue Sep-20-05 03:06 PM
Response to Original message
2. The lower the pressure, the faster air moves in to fill it.
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eallen Donating Member (1000+ posts) Send PM | Profile | Ignore Tue Sep-20-05 03:09 PM
Response to Original message
4. Yep. Think of a toilet flushing.
When water enters from the tank, that creates a pressure differential. The water wants to flow down the pipe, but any random rotation picks up speed as the water nears the center of the tank, causing rapid circulation. This increase is caused by conservation of angular momentum, much as a ballerina picks up speed when she brings her arms inward.

A low pressure system works much the same way. Warmer air wants to flow up the low into the upper atmosphere. This is accelerated when it lets loose rain. Other air comes in to replace it. All that air rushing inward causes the latent circulation of the coriolis force to be multiplied, causing a rotation, counterclockwise in the northern atmosphere.

Of course, that's simplified. If you want the fifty cent explanation, you have to pony up. ;D
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MoonRiver Donating Member (1000+ posts) Send PM | Profile | Ignore Tue Sep-20-05 03:11 PM
Response to Reply #4
7. I'd pay but I probably wouldn't understand the math!
Thanks for the explanation. That makes sense.
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w13rd0 Donating Member (1000+ posts) Send PM | Profile | Ignore Tue Sep-20-05 03:09 PM
Response to Original message
5. Yes
Ever been to the science museum? Where they have the "tornado machine"? It works by sucking air from the center, and jetting out air on the sides...thus, a "low pressure" area is created in the center of a circulating air system...heck, same thing with a sink drain.
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maine_raptor Donating Member (1000+ posts) Send PM | Profile | Ignore Tue Sep-20-05 03:09 PM
Response to Original message
6. Yes
As the pressure in the center of the storm decreases, air moves faster into that point. It swirls counter-clockwise due to the rotation of the Earth. It is similar to water draining from a bathtub.

One of the best way to tell how powerful a hurricane will be is to watch the rate that the air pressure drops within the "eye".
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MoonRiver Donating Member (1000+ posts) Send PM | Profile | Ignore Tue Sep-20-05 03:13 PM
Response to Original message
8. Thanks guys! Great info!
Since we'll be dealing a lot with extreme weather conditions, I just wanted to know what's going on.
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Rude Horner Donating Member (1000+ posts) Send PM | Profile | Ignore Tue Sep-20-05 03:20 PM
Response to Original message
10. All that science stuff is pure mumbo jumbo
See in reality, God creates the REALLY big storms because he wants to punish homosexuals, and other deviant lifestyles. See what happens is, God looks down on the Earth and notices that...oh, say for example...that Mardi Gras is coming up soon in New Orleans. And see, God thinks that all that devilish behavior needs punishing, so he blows really hard and then the clouds start spinning, and then ....well, a hurricane is formed. It's all right there in the bible.

:sarcasm:
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MoonRiver Donating Member (1000+ posts) Send PM | Profile | Ignore Tue Sep-20-05 03:34 PM
Response to Reply #10
15. Oh man, I didn't know it was so simple!
:D
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leftofthedial Donating Member (1000+ posts) Send PM | Profile | Ignore Tue Sep-20-05 03:21 PM
Response to Original message
11. think of yourself as a storm. You are wild and rambunctious.
Now think of high pressure as a very large person sitting on you.
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Ready4Change Donating Member (1000+ posts) Send PM | Profile | Ignore Tue Sep-20-05 03:33 PM
Response to Original message
14. Barometric pressure indicates the presence of a vacuum.
Or rather, it indicates what areas of air are at what levels of pressure. It doesn't create anything. It's just a measurement, like inches or pounds or gallons.

What creates storm/wind activity is, ultimately, the Sun. It warms up the lands and the oceans. Those in turn warm up the surrounding air. Then, just like with a hot air balloon, some of that warm air rises, creating an area of lowered pressure behind.

Thus the Sun, and heat, are the engines of not only big storms like Katrina, but also tornados, as well as gentler things such as ocean breezes.
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HereSince1628 Donating Member (1000+ posts) Send PM | Profile | Ignore Tue Sep-20-05 03:36 PM
Response to Original message
18. Low pressure sucks, lower pressure sucks MORE
Edited on Tue Sep-20-05 03:36 PM by HereSince1628
THe more it sucks the faster the wind moves!
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HereSince1628 Donating Member (1000+ posts) Send PM | Profile | Ignore Tue Sep-20-05 03:37 PM
Response to Reply #18
19. Which of course is complicated by Coriolis effect as the storm moves north
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applegrove Donating Member (1000+ posts) Send PM | Profile | Ignore Tue Sep-20-05 06:47 PM
Response to Original message
22. I think the hurricane sucks all air into the vortex and then the barometer
pressure is lower just before the storm. All the air is in one place.
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msongs Donating Member (1000+ posts) Send PM | Profile | Ignore Tue Sep-20-05 07:12 PM
Response to Original message
24. air in a low pressure center is RISING UP, thus presses down less ->
Part A: in a high pressure center the air is sinking towards the earth, thus applying more pressure. in a low pressure center the air rises, thus decreasing the downward pressure/weight of the atmosphere.

It is the opposite of a toilet flushing, which water goes down, that would be like high pressure.

air sinks in a high pressure zone, hits the earth, and flows outwards to a low pressure center where the air then rises again. After the air has risen to maximum height it flows to wards a high pressure center where it sinks again.

part B: when very warm air containing a lot of moisture rises, thus lowering the pressure, the air cools and condenses out the water vapor as clouds and if enough moisture is present, creating rain. The creation and falling of rain releases the heat. The greater the rising air and creation of rain, the faster the air will move upwards.

the spining of the earth causes the air to spiral into and upwards in a low, and downwards and out in a high.

if you read the NOAA reports they talk about convection in the storm center. That is merely the rising air creating thunderstorms. they also mention the temperature of the cloud tops...the colder the tops means the high they are, thus the greater the amount of heat released, the greater amount the air is rising, thus the lower the pressure.

Msongs
www.msongs.com/clark2008.htm

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