August 30th, 2011
11:23 AM ET

How Irene's forecast missed the mark and why it could happen again

They know they missed it. Forecasters at the National Hurricane Center in Miami say when it comes to the strength of Hurricane Irene as it approached North Carolina, they know they were off. Way off.

“At least in the guidance we were looking at there was no indication of anything that would cause the storm to weaken. So, we thought we would have a Category 3 at landfall,” said Bill Read, the director of the Hurricane Center. Irene came in at a Category 1, the weakest. Read said there’s good reason they were so far off.

The science of forecasting how strong or weak a storm will become is simply not very good. With Irene, forecasters say they weren’t even as good as their five-year average.

“Every storm comes up with a surprise,” Read said. “In this case it was one where it went downhill. Charlie a few years ago is one that went uphill. Neither case did we see that coming, and that’s my measure of the fact that we have a long way to go.”

Bill Read, of the National Hurricane Center, talks about the difficulty of predicting hurricanes.

Hurricane forecasters say they want to get it right all the time. But if you are going to be wrong, they say it's better to be wrong in weakening storms like Irene.

“I’d say a bigger worry than one weakening at landfall is the ’35 hurricane that came through the Keys," Read said. "Charlie if it’s a little bigger. Audrey in 1957. Get the picture?”

In all of these cases, the storms rapidly intensified as they neared the coastline. By then, it’s too late to order massive evacuations.

CNN's severe weather expert Chad Meyers said when Hurricane Irene smashed into the Outer Banks of North Carolina, the contact weakened the storm.

So, forecasters had the path right, but the impact of landfall changed what the amount of destruction would be in some areas. Wind shear helped knock down velocity, and unexpected dry air sucked some of the power out of the storm.

"It literally knocked the stuffing out of the eye," Myers said. "It never got its mojo back."

Meteorologists measured pressure levels inside the storm that could have allowed it to strengthen back into a Category 3 hurricane, Myers said, but Irene's romp over land in North Carolina prevented the eye wall from spinning into a more destructive storm by the time it arrived in New York.

"It never had that opportunity because North Carolina got in the way, dry air came across over Virginia and Maryland and got in the way, and although this was very low pressure, the reason why we could never let the guard down for New York City ... was because the pressure was low enough that at any time, if this storm decided to get its act together, it could have gone from a 60-70-80 miles per hour storm - it easily could have been a 110 (miles per hour) storm like it was in the Caribbean and like it was in the Bahamas."

Add to that the difficulties of having true accurate model data when it comes to hurricane forecasts.

“Real-time observations, like that collected by NOAA’s Hurricane Hunters, are put into these models to hopefully give a more accurate forecast. We are much more accurate on forecasting severe storms and their behavior for this very reason, the availability of observations," CNN meteorologist and weather producer Sarah Dillingham said. "These storms occur over land, allowing scientists to take measurements within those storms and use that data to run computer models. Think about a hurricane, over water, with no way to collect data except from above.

"Makes it difficult to see what is actually going on, right?"

Dillingham said dropsondes, instruments that are dropped from above and into these storms, are used to collect data inside hurricanes as they fall to the surface.

"This is helpful, but you are also trying to view the data it collected, track where it was in the storm, and at the same time determine what that means from a scientific perspective," she said. "Also, you may think, what about trying to send something up into the storm from below. In a hurricane? Good luck with that."

Dillingham said "the sparsity of real-time observations in tropical systems is what makes it so difficult to produce a more correct intensity forecast, and certainly makes it difficult to improve them."

"The track of these storms depends on atmospheric winds and surrounding storm systems, and we understand these factors much better, giving us a better handle on the 'steering' of these systems," she said. "This makes tracking more accurate overall. Things like RI, or rapid intensification, in tropical cyclones is just not fully understood yet, and until we can obtain that vital observational data within these storms - while they are over open, warm waters - we will struggle to model these kinds of processes.”

For that reason, Dillingham said Read's explanation of why they have trouble making these predictions is spot on.

And that's also why Read says the decisions to evacuate made by emergency managers and state and federal officials was the right one.

In every aspect of the storm except for wind speed, Read says, they got it right.

According to their initial analysis, the track forecast of the storm was 20% better than their five-year average. They do very well at predicting the path of a hurricane.

“We had storm surge flooding all the way up from the Carolinas into New England," Read said. We’ve had tremendous and tragic rainfall flooding. We’ve had loss of life from trees down well inland and the power outages.”

Hurricane forecasters admit their ability to foresee a storm’s strength is not much more today than it was 20 or 30 years ago.

According to the Hurricane Center’s initial analysis, “Irene exemplifies the state of the science.” They are pinning their future hopes on programs like the Hurricane Forecast Improvement Project. Scientists say they are seeing some promising results. This program uses high-resolution models and enhanced Doppler radars to measure the core of Hurricanes.

Forecasters say that three out of four times you will likely be asked to evacuate and you’ll coming back saying "Why did I leave?"

But that fourth time, if you don’t, Read says, you’ll wish you had.

Post by:
Filed under: Flooding • Hurricane Irene • Hurricanes • Weather
soundoff (639 Responses)
  1. rjb1971

    Really Susan?

    August 30, 2011 at 1:25 pm | Report abuse |
  2. Maryann - Orlando FL

    I thought everyone knew that a hurricane loses strength when it passes over land. North Carolina IS land.

    And I'm not even a meteorologist.

    August 30, 2011 at 1:25 pm | Report abuse |
    • Rob

      not to disagree with your point but the storm went over the intracoastal waterway in NC....which is water....warm water

      August 30, 2011 at 1:33 pm | Report abuse |
    • brad-ash

      outer banks are a bunch of sand not water. there is a intercoastal waterway between the banks and mainland. Point is a large portion of the western side of the storm was completely over land, and the eye made landfall in NC...then 2 other places.

      August 30, 2011 at 1:39 pm | Report abuse |
    • propmgr

      You are correct, however, forecasters though Irene would move back out over water and gain strength again...

      August 30, 2011 at 1:41 pm | Report abuse |
  3. zorbitearth

    Chad – Well stated. Great reporting.

    August 30, 2011 at 1:26 pm | Report abuse |
  4. Pvtpilot

    Overall the weather service does a wonderful job day in and day out. Storms of this size don't always follow the rules whether we like it or not. Try denying yourself the weather reports for a month a see just how much they help in planning your daily life.

    August 30, 2011 at 1:26 pm | Report abuse |
  5. Waqas

    I like to see the people complaining predict a storm. Be happy the negative happened and not the opposite or you wouldn't have "homes" to return to right now. Honestly, instead of being happy to have survived widespread damage, the lazy complain they had to get off their couch and move. Think about it this way, if those people didn't warn you in the first place, you might be dead.

    August 30, 2011 at 1:26 pm | Report abuse |
    • Gustavo

      That's because people will NEVER EVER be satisfied with anything. We always want more and more. It's like a person winning the lottery and complaining they have to pay taxes on it. Until they loose their house and their loved ones and then they complain that why wasn't evacuations ordered. It truly is sickening to see that some people think that way and can be so damn ignorant about life.

      August 30, 2011 at 1:49 pm | Report abuse |
  6. Maggie

    I have learned, living in different parts of the world, that you can never, ever, underestimate the power of Mother Nature!

    August 30, 2011 at 1:27 pm | Report abuse |
  7. Ben

    You're asking people to predict the future, of course they won't always be correct. Personally for something like this, I would rather hear that it's going to be worse and have it be better than hear that it's going to be better and then be worse, that way precautions are taken.

    August 30, 2011 at 1:27 pm | Report abuse |
  8. clinky

    The story is a cover-up. What they're not reporting is that the storm would have had to be on a perfect track and at fullest intensity for the range predicted to have done the damage that was foretold over and over.

    Hyping these storms hypes the news networks that cover them. It also allows corporations like CNN to simplify and thus further control what qualifies as "news." The one prediction you can bank on is that from now on every hurricane will push off everything else that's reported for a week, an opportunity to make our news coverage even thinner.

    August 30, 2011 at 1:27 pm | Report abuse |
    • bill

      You are a sad, lonely, little man...

      August 30, 2011 at 1:34 pm | Report abuse |
    • Gustavo

      Bet you also believe in unicorns and that we never landed on the moon hu?

      August 30, 2011 at 1:50 pm | Report abuse |
    • clinky

      Gustavo, Neither. Bill, Sounds like they got to you too : )

      August 30, 2011 at 2:11 pm | Report abuse |
  9. Chris

    Predicting weather is a study in chaos theory. It's actually impressive how good they are at it and this, to me, is a pretty good example. They got virtually everything RIGHT about this storm other than the intensity.

    And clearly it paid off to be cautious here. Recall at least 30 people have died to date due to this storm with the precautions we took.

    By the way, equating what happens in storm systems vs. what is happening on the entire planet is a false comparison. If we continually add heat to water, we know it will boil. We don't, yet, have the science, to be able to predict where each bubble will be, how big it will be, or when it will burst.

    Never-the-less, we know that when we add heat, it will, eventually boil...

    August 30, 2011 at 1:28 pm | Report abuse |
  10. Rich

    Well...there was this one naked guy in Virginia Beach running around behind the Weather Channel crew during their broadcast that seemed to have a barometer in his shorts...

    August 30, 2011 at 1:28 pm | Report abuse |
    • Rob

      which is it? naked or wearing shorts?

      August 30, 2011 at 1:29 pm | Report abuse |
    • brad-ash

      i don't get it...if he was naked, how could he be wearing shorts?

      August 30, 2011 at 1:29 pm | Report abuse |
    • Rich

      He was wearing shorts at first, then (I guess) he was trying to show the storm's intensity by pulling his shorts down and dancing around on camera...google Weather Channel Streaker.

      August 30, 2011 at 1:38 pm | Report abuse |
  11. Rob

    This is not much different than when boxers fabricate controversy in order to hype up their PPV....it's all the hype machine to get ratings...

    August 30, 2011 at 1:28 pm | Report abuse |
    • clinky

      Not only ratings, Rob. The more simplistic the news gets, the lower expectations and critical evaluation by the viewership becomes, which makes advertising on these shows more effective and easier to do. CNN is no less about the bottom line than any other company. It does not exist to deliver accurate and detailed news but to make money.

      August 30, 2011 at 1:38 pm | Report abuse |
  12. brad-ash

    I think forecasters must have known it was weakening prior to NC hit. It was obvious to me as you looked at the radar Friday...winds decreasing and eye of storm less obvious and intense. But at that point they didnt change overall forecast...perhaps they were afraid to be held accountable if people dismissed the danger. As it reduced to level 1 near NC, it is clear that proximity to land would only lead to more weakening. But everyone, especially the media, is in the business to increase ratings and sell ads, so making it as big a news story as possible is standard course.

    August 30, 2011 at 1:28 pm | Report abuse |
    • propmgr

      Forecasters thought the hurricane was going to go back east and gain strength...

      August 30, 2011 at 1:45 pm | Report abuse |
    • Brandon

      Did you even read the story. It clearly said that although it was weakining, the concern was that there was enough pressure in the center for it to reform into a cat. 3 at a moments notice. Thats why they were over cautious. Not some hype about ratings. People just love to believe conspiracies, don't they.

      August 30, 2011 at 1:46 pm | Report abuse |
    • brad-ash

      I did read the story...and point is that they cannot forecast intensity any better than 20 years ago. It would be pretty rare for a storm to strengthen heading that far north and hugging the coast (land) as the path clearly predicted. Better safe than sorry I suppose, but there is a downside to overhyping too. I don't suggest a conspiracy...its pretty open and obvious. The news overhypes stories to sell.

      August 30, 2011 at 2:04 pm | Report abuse |
    • clinky

      Brandon, You left out an important qualification from the quote in the article: "if this storm got its act together." That's the crux of the matter. What were the odds of that happening? All of the conditions would have had to be ripe for the storm to do the devastation that CNN talked about on and on and on. At some point, getting people to quake in their boots over what could happen in the next week but very likely won't is preposterous, and it can be used as a manipulative trick.

      August 30, 2011 at 2:06 pm | Report abuse |
  13. Joe

    Meteorologist is the only job in the world where you can be wrong more often than right and still draw a paycheck.

    August 30, 2011 at 1:28 pm | Report abuse |
    • Mike

      Meteorologists and baseball players. The best hitters fail 70% of the time.

      August 30, 2011 at 1:32 pm | Report abuse |
    • Sean

      "Only job you get paid to get it more wrong than right"...

      I thought that was baseball (only average a hit 1 out of 3 time and get paid millions)

      August 30, 2011 at 1:33 pm | Report abuse |
    • Sean

      Ha! Nice Mike, you beat me to it by 1 minute...

      August 30, 2011 at 1:34 pm | Report abuse |
    • JMBR

      Read up on DARPA, they fail quite a bit. Latest failure: Hypersonic Airplane. But in their failure, we have such great inventions such as GPS and the Internet.

      August 30, 2011 at 1:41 pm | Report abuse |
    • Chuck

      I would include Economists in that category 😉

      August 30, 2011 at 2:03 pm | Report abuse |
  14. Doug

    The orders to evacuate the effected areas was the right thing too do....it saved lives.

    August 30, 2011 at 1:28 pm | Report abuse |
  15. Mike L.

    What is amazing is that we spend millions of dollars to support this agency; putting service people in harms way to fly into the eyes of these storms, dropping electronic gadgetry to better understand the dynamics but still don't fully understand them. Can I ask, what is the ultimate goal? Is there any value to be gained from spending all this money or is it just for the sake of knowing? People died from this storm even though the forecast was overstated. Why not save the money and just tell everyone a big storm is coming?? Same end result but less expensive.

    August 30, 2011 at 1:29 pm | Report abuse |
    • brad-ash

      thats a pretty incredible simplification.... They predicted its path almost precisely. 50 years ago, you wouldn't have had even 24 hours notice that a hurricane would hit you. So lets not be ignorant that forecasting is vastly improved compared to 50, 20 or even 10 years ago. Now they need to work on intensity forecasting. Science and technology advances in steps... perfection hasn't been reached in any field.

      August 30, 2011 at 1:35 pm | Report abuse |
    • Not afraid to work

      You are so lazy. If it is going to take more than a little effort to learn something, then you don't want to be bothered. Fortunately Edison was not as lazy as you. Progress and learning require investment and work. Don't you have a football game to watch. Oh, and don't bother predicting who is going to win.

      August 30, 2011 at 1:43 pm | Report abuse |
    • Mike L.

      Predicting the path could be accomplished without spending 100's of millions of dollars and contrary to the comment about being almost precise, they were off the mark in several places. As to whether I'm lazy or not, that has nothing to do with the argument I'm trying to make, which is that our government spends way too much money on things of negligible value. The hurricane intensity was TWO categories LESS than predicted, the entire east coast was warned, and yet people still died. Will we ever be able to stop or even lessen the severity of these storms? No, so stop wasting money. Contrary to your ad hominem attack, I am not lazy and think learning is essential but not at always at the expense of taxpayers. Edison wasn't sucking from the government teat while doing his work.

      August 31, 2011 at 10:52 am | Report abuse |
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26