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.

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

    If they can't get the weather right from day to day. If their predictions of the hurricane levels are any better than 20 years ago then why in the world would anyone listen to them regarding Global Warming, Climate Changes, etc. Seems to me that they are just throwing darts in the dark and hoping they miss their mark. I guess they need to keep their grants funded some way. Scare tactics always were a good bet.

    August 30, 2011 at 3:12 pm | Report abuse |
    • basketcase

      Predicting climate shifts and day to day weather patterns are entirely different fields. You are talking about two different "they"s doing two vastly different things. Try again.

      August 30, 2011 at 3:14 pm | Report abuse |
    • @ moin

      First of all.... these are not the same peolple who claim this... and are 2 diff. fields of expertise. SO thanks for coming out

      August 30, 2011 at 3:18 pm | Report abuse |
    • bridgmjm

      They just pull an OJ and take a stab at it.

      August 30, 2011 at 3:20 pm | Report abuse |
    • dhue

      i think we should take it easy on the forecasters, even though a lot of money is spent on these types of things we are still dealing with mother nature. there are too many variables involved to be so nit-picky in my opinion. i live one block from the ocean and am fully aware of the potential consequences of where i live. a storm is a storm. i have empathy for the people who perished as well as those that suffered damage but, that is the price of living on planet earth. we cannot control nature.

      August 30, 2011 at 3:22 pm | Report abuse |
    • JohninRal

      Climate and weather are different. To use a sports analogy, weather is predicting what a football team will do on on the next play. Climate is keeping track of the statistics over every season of every team in any situation.

      August 30, 2011 at 3:24 pm | Report abuse |
    • Bob Sled

      Some simple instructions: 1. Grab dictionary. 2. Look up "climate". 3. Look up "weather". 4. Compare the two. That should help, unless are you claiming that the dictionary was created as part of some elaborate environmentalist conspiracy as well?

      August 30, 2011 at 3:30 pm | Report abuse |
    • gelbstoff

      Bobbi's comment is based in two incorrect assumptions and is very simplistic. First, meteorologists are doing extremely well at predicting weather. Clearly, they can predict hurricane trajectory very well. This should be obvious for anyone older than 20 who pays attention to the weather forecast. The problem depicted in the article is the prediction of hurricane intensification. This is more a problem with availability of data to initialize models. Second, weather forecasting and climatology are different fields. One cannot say that because weather forecasting is bad (which is not) climate prediction also has to be bad.

      August 30, 2011 at 3:34 pm | Report abuse |
    • been there done that

      You're and idiot! Obviously you have never been through a hurricane.

      August 30, 2011 at 3:40 pm | Report abuse |
    • Bobbi

      I love it!!! Al Gore's minions are out in full force today. Fabulous. Such precious little duckies you all are. Continue to contribute to his million dollar scheme if it makes you all so happy. BTW, Climate change will ALWAYS occur as a result of solar flares, volcanoes, shifting weather patterns, you name it. But if you want to buy your expensive mercury filled light bulbs and make the liberals all rich and happy, go for it. Not to mention all those wonderful "green" jobs. Also, some of you may want to take a prozac and come back off the ledge.

      August 30, 2011 at 4:17 pm | Report abuse |
  2. Reflecting Pool

    Their prediction of the trajectory was mind-bogglingly accurate all the way. But meterologists seemed to abandon or disregard their own long-standing, well-established rules about hurricane weakening. They have always said, as long as anyone can remember, that once a hurricane hits any kind of land mass, it weakens rapidly and substantially. And they have always said, ad nauseam, that the colder northern Atlantic waters will serve to rapidly disempower a hurricane. And they have always said that when the eye wall and the eye of a hurricane becomes less defined and less identifiable, it is a sure sign the hurricane is disintegrating and degrading.

    Irene did all of these things even before it hit land in North Carolina, but the signals were ignored. And while meterologists ignored clear signs of degradation, they failed to adequately stress that the most destructive part of a hurricane is always – REPEAT – ALWAYS the flooding caused by torrential rainfall, which is NOT mitigated when a hurricane rapidly degrades in wind strength. Meteorologists made the same mistake ill-informed ordinary citizens make, namely, they were overly focused on the wind-speed issue and thus failed to realize (or remember) that the greatest destructive force of a hurricane is the torrential rains it brings – even when its wind speeds have been decimated to a mild roar. In this respect, we have failed to learn from Katrina – because that's exactly what happened there and that is why everyone initially (and erroneously) thought New Orleans had dodged the bullet after it passed – Because they were overly focused on the 'wind speed' issue not the flooding from torrential rainfall. It's hard to see a learning curve here.

    August 30, 2011 at 3:12 pm | Report abuse |
    • TR scientist

      You are absolutely correct. My question is why has this been snowed under in this report. A first year atmospherics student knows this. I can't believe NOAA has completely disreguarded basic physics and the effects of convection on a hurricane.

      August 30, 2011 at 3:16 pm | Report abuse |
    • basketcase

      First, they were afraid that it could miss an actual landfall, and thus maintain some of its strength. Second, the northern Atlantic is warmer than it often is, so they could have expected the weakening from these cold waters to be less. Third, there was a period that the eye/eye wall became more defined not long before hitting NC. Fourth, as the storm began to weaken and it became clear that it would not gain strength, they were CONSTANTLY emphasizing that the flooding rains and storm surge still posed serious threats.

      August 30, 2011 at 3:24 pm | Report abuse |
    • Bry

      it was wind speed in Katrina that pushed a 35 foot tall wave of water over Mississippi, and up the Mississippi river; the rain was mostly insignificant.

      August 30, 2011 at 3:28 pm | Report abuse |
  3. basketcase

    They did the right thing. They knew it had potential to strengthen, so they told the public that it could strengthen before landfall. To be angry that it did not is ridiculous.

    August 30, 2011 at 3:13 pm | Report abuse |
  4. nina valentino

    i just want to say that if people were not evacuated the death toll would have been higher. i feel bad that people don't see this and are shouting out complaints well grow up remember that tornado that rippid across US territory not to long ago stretching across how many states mississippi through up state into virginia?what about the surfers taken a risk on the damn waves during the storm dumb dumb but he is gone poor thing he should have taken alerts more serious i would rather be safe then sorry plain and simple. don't judge the weather teams they are doing their best and i respect them for it. would everyone had wished for a horrific landfall or what my god. just be happy it turned out this way but don't ignore future forcast. weather is unpredictable we are only human and trying to do the best we one can control air, wind, snow, ice or forest fires ect.....but you can prepare. at least new york has an idea now that it can happen and they need to be ready and shut down the busy city in order to save lives....i believe in forcasters also you need to remember the pictures of irene from space it was flippin huge looked like the movie "the day after tommorow" i was freaked out.

    August 30, 2011 at 3:13 pm | Report abuse |
  5. TR scientist

    What a load of crap. Hurricanes are very well understood. And from what I just heard from this report, there was one key thing that was over looked. That was water temperature. Hurricanes live and die off of water temperature. Not once have I heard any of the hurricane forecasters talk about the position of the Gulf Stream and Labrador currents during this forecast which are huge variables in predicting the strength. What I can tell you is NOAA and most of the government science agencies are a quagmire of stagnation when it comes to hiring talented scientist. Getting a job there is like winning the lottery and the lottery winners are not the best qualified.

    August 30, 2011 at 3:13 pm | Report abuse |
  6. Stewart

    Let us quit nitpicking! They are doing an EXCELLENT job. They are not God. Human beings can do only so much, even with technology. I would rather be safe than sorry – think of the alternatives to a little inconvenience and annoyance! The sage was right in saying "An ounce of prevention is better than a pound of cure".

    August 30, 2011 at 3:14 pm | Report abuse |
  7. Tony

    Wow you people need to get a grip. You expect something like a cable channel lineup, with up to the minute snapshot? The spaghetti models have become increasingly accurate. And if media did not go "over board" maybe even more people had drowned or whatever. This is serious business, get over yourselves!

    August 30, 2011 at 3:15 pm | Report abuse |
  8. Guillotina

    see "Uncertainty" definition

    August 30, 2011 at 3:16 pm | Report abuse |
  9. Steve

    Thanks media, for overhyping everything – it was sad that CNN had articles comparing Irene to Katrina, giving "advice" for how to behave in a hurricane, and other such things. Forecasters knew the eyewall was collapsed 2 days before the storm hit land, and no one realistically expected catastrophic damage... except for those poor news reporters in orange weatherproof suits, trying their best to make the storm look worse than it really was. Sad.

    August 30, 2011 at 3:19 pm | Report abuse |
  10. Arrowdog

    Models, Models, Models vs. human knowledge, jugement, and capabilities. My own mentor, back in 1990 when computer modeling was still developing put it to the best I have ever heard. A GOOD engineer (in this case meteorologist), knows the answer before performing the model. The model should be used only to verify and more accurately predict possible variations – in the hands of a TRUE expert. These type of analytical folks are disappearing, and those who aspire to higher standards are shunned like a leper. You see, those in the know believe that the computer, and the model, are the apex – not the actual person running them. We would be much better off investing in human capital, and developing human capabilities (kind of like we used to).

    August 30, 2011 at 3:20 pm | Report abuse |
  11. Rob

    I don't know, seems like the forcast hit the mark; there was plenty of devestation. oh, but it was poor little vermont et al, not new york. so who cares right? geez.

    August 30, 2011 at 3:20 pm | Report abuse |
  12. for real

    Dude .. why do you hate america? I don't believe u are Indian .. if you are then clean up your country first before pointing at others. . peace !

    August 30, 2011 at 3:21 pm | Report abuse |
  13. Jim

    It's all about AD revenue, especially for TWC. If they say the sky is falling, people will stay tuned.

    August 30, 2011 at 3:22 pm | Report abuse |
  14. sadat

    Is it such a bad thing that that they missed the mark? I for one am glad it wasn't as bad as they had predicted. the devastation around the east coast is bad enough as it is, i don't want to imagine how bad it would have been if it had been stronger the this.

    everybody chill and get off these people. would we rather they say it is a category 1 and then get hit by a cat 2 or 3 and get people killed or the other way. i can't understand why people are sweating these guys who are just trying to protect us all. come on people.

    August 30, 2011 at 3:22 pm | Report abuse |
  15. krehator

    People will complain either way. If they under prepare or over prepare they will gripe. People are generally whiners.

    August 30, 2011 at 3:23 pm | Report abuse |
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