Ned Potter is the science correspondent for ABC's "World News with Charles Gibson." He has reported on such topics as space exploration, the human genome and climate change.
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Hurricane Forecast
August 09, 2007 11:30 AM
Don't be lulled, says NOAA. This morning it updated its hurricane outlook for this year, and basically stuck to its guns, giving much the same numbers it had in May.
The summary is HERE. It predicts:
--13-16 named storms (down from 13-17)
--7-9 of those are likely to be hurricanes, with winds over 75 miles an hour (the May number was 7-10)
--3-5 "major" hurricanes--Category 3 or higher on the Saffir-Simpson Scale, with winds over 110 miles an hour.
Gerry Bell, the lead hurricane forecaster at NOAA's Climate Prediction Center, cites three reasons to believe the season is still likely to be an active one:
--Since 1995 we've been in the active part of the "Multi-Decadal Cycle" that typically lasts 25-40 years. During these periods, winds and temperatures favor storm formation. Since 1995, 9 of 12 hurricane seasons have been above average.
--The tropical Atlantic and Caribbean are both warmer than normal, providing fuel for storms.
--There appears to be a decent chance that a La Nina will form in the Pacific. You'll recall that a La Nina--the opposite of an El Nino--is a giant stripe of cooler-than-average water along the equator in the Pacific. It tends to rearrange the jet streams blowing over it. An El Nino tends to steer the jet streams southward as they reach the Atlantic--shearing the tops off of some hurricanes that would otherwise hit the U.S. coast. In the case of a La Nina, no such luck.
"This combination is known to produce very active seasons," said Bell in a teleconference a little while ago.
How can this be, when the season's been so quiet so far? One graph that's useful is HERE, showing that early storms--June to mid-August--are really very rare. There have been three named storms in the Atlantic so far this year; NOAA says there are typically two. The peak of the season is still a month away, in mid-September.
Bell cautions that all they're offering is a forecast of prevailing conditions for this year, and giving the number of storms that tend to form in similar years. They cannot say when or where specific storms might yet be, though Bell says that in years that looked like this one, there have, on average, been 2-4 storms that made landfall in the U.S.
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Added Note:
To Wes, Chuck, Andy, and all others who may pass this way--it's great to hear your voices...or see your posts...or whatever.
Wes and Chuck asked for more about the Atlantic Multidecadal Oscillation, which seems to be a major factor in the number of hurricanes each year, and I'm happy to oblige. NOAA's Atlantic Oceanographic and Meteorological Laboratory has done a helpful Q&A on it, which you can find HERE.
Nobody can say how long the "warm" phase of the cycle lasts; the best estimate is 25-40 years, which means that if the current phase began in 1995, it has another 15-30 years to go. The last "cold period," when there were consistently fewer hurricanes, seems to have run through the 1970s and 80s, though it was only in the 1990s that meteorologists really caught on to it.
Andy, I'm not in the least worried about hurricanes. I'm totally freaked out about those colliding galaxies.
August 9, 2007 | Permalink | Share | User Comments (9)
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You mentioned a multidecadal cycle. How long has this cycle been evident? How much can individual years deviate from the trend of the cycle?
Interesting post. Thanks, Ned.
Wes
Posted by: Wes | Aug 9, 2007 1:30:33 PM
How can you worry about hurricanes when galaxies are colliding?
Ever notice how hurricanes are shaped like galaxies? It's always fascinated me that astronomers can predict the trajectories of galaxies, but weather folk can only make educated guesses on the path of a hurricane. Maybe the two disciplines need to compare notes.
Posted by: Andy | Aug 9, 2007 1:31:56 PM
I suppose that NOAA is forecasting a bit on the pessimistic side, especially after the diastrous hurricane season of 2005, because it doesn't want to take anything for granted. Better safe than sorry, I guess.
Ned, I'd also like to echo Wes's question about what part of the multidecadal cycle we're now in, since it might give us some idea of how much longer these severe hurricane seasons will last. You might also want to offer some words of reassurance to Andy about the upcoming galaxy collision. I think this really has him so worried he's now sounding like Andy Rooney.
Posted by: chuck | Aug 9, 2007 1:43:16 PM
HA!! Worried about the galaxy collisions Andy and Ned?? You should be worried about Mars colliding with the Earth since it's going to get so close to us that it'll be as big as the full moon. My email inbox has been flooded with emails stating this. So look out on August 27, because thats what you should be worried about, not a mesely four galaxies merging!!!
Interesting about the multidecadal cycle. I've never heard of that before. El Nino and La Nina I've heard of. I'll have to look into this more. Also interesting that they're still calling for an active season, when we've had, I think, 2 storms in the Atlantic, and they were either tropical depressions or weak tropical storms. Also makes me wonder how they can predict an entire season of hurricanes when the weatherman is usually wrong about the forecast only 2 days out. Strange.
Posted by: Lawrence | Aug 9, 2007 9:32:20 PM
As an addendum to my previous post, I can't help but wonder if those cataclysmic events in the universe don't have some effect on massive events here on our planet. Gravity is gravity, after all. Since science can take it into account for galactic hijinks, then it must have some effect on large, mobile masses here on Earth. Perhaps someone could construct a database to correlate hurricane motion with extra-planetary goings-on.
And Lawrence, if Mars gets close enough that it's the size of the full moon, we'll have other problems before the collision is upon us.
Posted by: Andy | Aug 10, 2007 8:14:34 AM
Ned, many thanks for the additional information from NOAA about the Atlantic Multidecadal Oscillation (and isn't that a wonderful term to throw into casual conversation?). Now that I understand a bit more about the AMO, I guess I can start worrying along with the rest of you about the impending collision of galaxies.
Andy, I think your idea of a database to correlate galactic occurrences with earthly phenomena is a good one. There might not be a great deal of correlation, but we just might find some links we've never considered before. And Lawrence, as for the approach of Mars, I'm reminded of the classic 1951 movie "When Worlds Collide," which I hope doesn't happen to us!
Posted by: chuck | Aug 10, 2007 8:25:55 AM
So if hurricane season is going to be so bad this year, the question that BEGS to be asked now is:
Are WE (the East Coast) READY?
We just had some torrential rain this past Wednesday in the New York City area -- storms that dumped 3-inches of water in a few(?) hours, managed to really screw-up the NYC subway system and (of course) flooded nearly all of the metropolitan-area highways! (And what about that F2 tornado that touched down in Brooklyn? Yikes!)
I shudder to think what a seriously massive, Category 3 or 4 hurricane will do to my beloved city or any other -- especially N'Orleans or any of those areas still trying to recover from Katrina/Rita.
And as for the Mars thing... WE all know that NOT entirely TRUE, right?
Posted by: redtech5 | Aug 10, 2007 10:09:58 AM
Redtech5 comes through, again. NYC has been warned many times about the results of a Category 3 hurricane's effect on the city. I do hope they take the warnings to heart. If a bad rainstorm can do so much damage, imagine what a heavy storm surge laden with salt water could do. A tornado in Brooklyn? (I was born in Brooklyn, but I was naturalized at a very young age.) What's next? Honesty in Washington, D. C.? Can we stand up to such upheaval?
I'm afraid the Mars thing has been debunked several times over the past couple of years, but it's still fun to see how people react to the news.
Posted by: Andy | Aug 10, 2007 11:35:48 AM
Yea, I've been getting the Mars emails for weeks now. I'm actually getting tired of explaining why it's wrong all the time. And the way it's written makes it sound believable, and in fact, true. Oh well.
And honesty in D.C.??? That would turn the country upside down. I don't know if we can handle such a travesty.
Posted by: Lawrence | Aug 12, 2007 12:42:14 PM
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