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CNN Live Today

Look at Science Behind Hurricanes

Aired October 03, 2002 - 10:17   ET

THIS IS A RUSH TRANSCRIPT. THIS COPY MAY NOT BE IN ITS FINAL FORM AND MAY BE UPDATED.

THIS IS A RUSH TRANSCRIPT. THIS COPY MAY NOT BE IN ITS FINAL FORM AND MAY BE UPDATED.


MILES O'BRIEN, CNN ANCHOR: Before we go down to the Hurricane Center to get a little information about this, let's just bring you up to date on what we know about the storm: no significant road closures, no significant delays at the airport in New Orleans. There were some flight cancellations, of course, but generally speaking, as the storm had petered out, the problems haven't been so bad. We will watch that storm surge and the potential flooding to see what goes on there, but generally speaking, the folks in that area very, very lucky.
For more on this, let's turn to CNN's Mark Potter who is at the Hurricane Center in Miami. He's been watching this all along.

Mark, this is fascinating stuff. As much as we know about hurricanes, there's a lot we still don't know.

First of all, let's talk about the track. The track was amazingly accurate, the track prediction. That is where the state of the art and the science is very obvious, isn't it?

POTTER: Absolutely. The track for days was very good. We looked back at the track from several days ago, and it had it landing a few miles west of where it actually hit. That is an amazing success. The problem that they had is with the intensity forecast. That's always a hard thing to do here at the National Hurricane Center, and Max Mayfield, the director, said that as they go forward with the search, that's the area where they're going to try to get more money and spend the money to do better. And this turned out to be a surprise in a couple of different ways.

O'BRIEN: Let's bring up a radar for just a moment. We'll give folks an idea of what really happened as Hurricane Lili came ashore. Now first of all, any time a hurricane comes ashore, it loses its source of fuel, which is warm water, but what happened here in addition to this, I don't know if you can see, right down in there, you can see that the storm's cyclonic activity kind of broke apart there. What was happening was dry air from the west was coming in. It kind of intertwined with that counterclockwise swirl, and as the dry air got in there, it broke it apart, and that drastically reduces its strength, reducing the amount of winds. Some of that is very predictable, isn't it, Mark?

POTTER: Yes, it is. But what was unpredictable just a few hours ago is that that they didn't see that dry air coming from the West, and the breakup on land usually occurs further inland than it was this time. The interaction with land just begun. It was really was that dry air mass from the west that came in and commingled and became part of the swirl and break apart the eye and weakened the storm. The big question that the forecasters are going to wrestle with for a long time and those people seeking their Phds will wrestle with is, why did it become a category four in the first place? We just talked with Max Mayfield and he said there was an interesting fight here yesterday at the Hurricane Center between the forecasters and their computers. The forecasters in their hearts felt that this storm was going to blow up bigger than it was. The computer models was saying exactly the opposite, that it would stay the same, if not diminish.

But then it did blow up, that's where the surprise occurred, and it occurred in part of the Gulf where typically that doesn't happen. It happened in the northern part of the Gulf, which is normally not as favorable, as conducive to expansion or intensification as south of the 25th parallel. And, so, lots of surprises, lots of question. It's really detective work without all the answers yet.

O'BRIEN: It is interesting that their computers told them one thing, and in their gut, they thought another. It makes it difficult for forecasters.

Let's take a look at a 3D picture that NASA put together, a hurricane almost in the generic form here, and as you look at this, you get a sense of how it actually builds up. It starts with a little wrinkle of a wave in the Sub-Sahara, the trades winds bring it across the Atlantic, the warm waters of the Atlantic -- 80 degrees is the magic number, 80 and above is what fuels these things, and literally pulls water out of the ocean in that counterclockwise flow, as you can see there. Those aren't little pieces of paper in there. That's to give you the idea of the flow of the hurricane it creates that huge mass of a storm. If you look at a shot from the space shuttle, shot a few years ago, this is a shot of a typhoon, which the shuttle captured from 250 miles up. You see very distinctly, there is the eye, and as you get away from the eye, those winds sort of dissipate. The closer you are to the eye, the higher they are.

But without water, you're not going to have a hurricane. So, as we say, Mark, some of this is predictable, but the fact that it fell apart so quickly is really interesting, isn't it?

POTTER: Absolutely. And another thing to contemplate is where this storm was just a few days ago. When it was in the central Caribbean, it was almost written off. It was a tropical storm, and then it went down to a depression, but I must say that the director here and the forecasters here were saying, we have to keep an eye on this one, even though it will not go anywhere right now. It looks like it is totally breaking apart, because any time you have a storm like this in the Gulf, in the Caribbean, this time of year, you have to always watch it, because this sort of thing can happen, as it exactly did. And so they watched it. This is another classic case you have to watch it all the way to the end because you just never know, and they don't have all the answers, and they'll be studying this one for a long time to come.

O'BRIEN: CNN's Mark Potter, where they study hurricanes, part science, part guesswork. Let's face it, the bottom line is, there's mysteries when you're talking about something as big as this.

TO ORDER A VIDEO OF THIS TRANSCRIPT, PLEASE CALL 800-CNN-NEWS OR USE OUR SECURE ONLINE ORDER FORM LOCATED AT www.fdch.com






Aired October 3, 2002 - 10:17   ET
THIS IS A RUSH TRANSCRIPT. THIS COPY MAY NOT BE IN ITS FINAL FORM AND MAY BE UPDATED.
MILES O'BRIEN, CNN ANCHOR: Before we go down to the Hurricane Center to get a little information about this, let's just bring you up to date on what we know about the storm: no significant road closures, no significant delays at the airport in New Orleans. There were some flight cancellations, of course, but generally speaking, as the storm had petered out, the problems haven't been so bad. We will watch that storm surge and the potential flooding to see what goes on there, but generally speaking, the folks in that area very, very lucky.
For more on this, let's turn to CNN's Mark Potter who is at the Hurricane Center in Miami. He's been watching this all along.

Mark, this is fascinating stuff. As much as we know about hurricanes, there's a lot we still don't know.

First of all, let's talk about the track. The track was amazingly accurate, the track prediction. That is where the state of the art and the science is very obvious, isn't it?

POTTER: Absolutely. The track for days was very good. We looked back at the track from several days ago, and it had it landing a few miles west of where it actually hit. That is an amazing success. The problem that they had is with the intensity forecast. That's always a hard thing to do here at the National Hurricane Center, and Max Mayfield, the director, said that as they go forward with the search, that's the area where they're going to try to get more money and spend the money to do better. And this turned out to be a surprise in a couple of different ways.

O'BRIEN: Let's bring up a radar for just a moment. We'll give folks an idea of what really happened as Hurricane Lili came ashore. Now first of all, any time a hurricane comes ashore, it loses its source of fuel, which is warm water, but what happened here in addition to this, I don't know if you can see, right down in there, you can see that the storm's cyclonic activity kind of broke apart there. What was happening was dry air from the west was coming in. It kind of intertwined with that counterclockwise swirl, and as the dry air got in there, it broke it apart, and that drastically reduces its strength, reducing the amount of winds. Some of that is very predictable, isn't it, Mark?

POTTER: Yes, it is. But what was unpredictable just a few hours ago is that that they didn't see that dry air coming from the West, and the breakup on land usually occurs further inland than it was this time. The interaction with land just begun. It was really was that dry air mass from the west that came in and commingled and became part of the swirl and break apart the eye and weakened the storm. The big question that the forecasters are going to wrestle with for a long time and those people seeking their Phds will wrestle with is, why did it become a category four in the first place? We just talked with Max Mayfield and he said there was an interesting fight here yesterday at the Hurricane Center between the forecasters and their computers. The forecasters in their hearts felt that this storm was going to blow up bigger than it was. The computer models was saying exactly the opposite, that it would stay the same, if not diminish.

But then it did blow up, that's where the surprise occurred, and it occurred in part of the Gulf where typically that doesn't happen. It happened in the northern part of the Gulf, which is normally not as favorable, as conducive to expansion or intensification as south of the 25th parallel. And, so, lots of surprises, lots of question. It's really detective work without all the answers yet.

O'BRIEN: It is interesting that their computers told them one thing, and in their gut, they thought another. It makes it difficult for forecasters.

Let's take a look at a 3D picture that NASA put together, a hurricane almost in the generic form here, and as you look at this, you get a sense of how it actually builds up. It starts with a little wrinkle of a wave in the Sub-Sahara, the trades winds bring it across the Atlantic, the warm waters of the Atlantic -- 80 degrees is the magic number, 80 and above is what fuels these things, and literally pulls water out of the ocean in that counterclockwise flow, as you can see there. Those aren't little pieces of paper in there. That's to give you the idea of the flow of the hurricane it creates that huge mass of a storm. If you look at a shot from the space shuttle, shot a few years ago, this is a shot of a typhoon, which the shuttle captured from 250 miles up. You see very distinctly, there is the eye, and as you get away from the eye, those winds sort of dissipate. The closer you are to the eye, the higher they are.

But without water, you're not going to have a hurricane. So, as we say, Mark, some of this is predictable, but the fact that it fell apart so quickly is really interesting, isn't it?

POTTER: Absolutely. And another thing to contemplate is where this storm was just a few days ago. When it was in the central Caribbean, it was almost written off. It was a tropical storm, and then it went down to a depression, but I must say that the director here and the forecasters here were saying, we have to keep an eye on this one, even though it will not go anywhere right now. It looks like it is totally breaking apart, because any time you have a storm like this in the Gulf, in the Caribbean, this time of year, you have to always watch it, because this sort of thing can happen, as it exactly did. And so they watched it. This is another classic case you have to watch it all the way to the end because you just never know, and they don't have all the answers, and they'll be studying this one for a long time to come.

O'BRIEN: CNN's Mark Potter, where they study hurricanes, part science, part guesswork. Let's face it, the bottom line is, there's mysteries when you're talking about something as big as this.

TO ORDER A VIDEO OF THIS TRANSCRIPT, PLEASE CALL 800-CNN-NEWS OR USE OUR SECURE ONLINE ORDER FORM LOCATED AT www.fdch.com