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. Lou


    Actually, I think you have neatly described yourself as an uncultured, perverted, inhuman, hypocritical, obnoxious, immoral, egocentric, insensitive, self-righteous b@st@rd.

    The difference, of course, is that I would never tar an entire people with the characteristics of a single individual. The Indians that I know are cultured, not preverted, quite human, rarely hypocritical, never obnoxious, quite moral, multicentric, sensitive, righteous but not self-righteous and quite legitimate. As are, naturally, my American friends. You, on the other hand, are a morally bankrupt, foul-mouthed perverted twit who likes to see his name in print.

    Have a nice day,


    August 30, 2011 at 2:37 pm | Report abuse |
    • MyWorld


      I totally agre with you.
      The Indians I know are really rich in Moral,Respect,etc. as my American friends.

      August 30, 2011 at 3:10 pm | Report abuse |
  2. Jim

    The depths of poverty in India are far greater than in the US. Compared to your poor, we don't even have "poor" - focus on your own house, we'll do our best to take care of ours (and give some money to help yours as well... $92 million in 2006 alone...).

    August 30, 2011 at 2:37 pm | Report abuse |
  3. tank

    Who cares about New York. Everything is so New York biased. New York is garbage

    August 30, 2011 at 2:38 pm | Report abuse |
  4. StarFleetVeteran

    Maybe because the news media likes to blow things all out of proportion to scare people and get more ratings? If you don't know that then you're pretty naive and deserve all the freaking out they make people do.

    August 30, 2011 at 2:38 pm | Report abuse |
    • McMoldy

      I think that the media was helping Obama with his katrina cred. Obama needed a katrina that wasn't a katrina so he could campaign about his masterful handling of a massive disaster that wasn't so massive. Never let a crisis go to waste, and in the event that there isn't a disaster, create one!

      August 30, 2011 at 2:50 pm | Report abuse |
  5. rohan

    Yeah, hope you storm chasers got off flying in that plane .... and wasting my tax money.
    You so know most of them do it for the thrill of it....and when it comes down TO ACTUALLY DOING SOME WORK IN ANALYZING THE DATA, its in the backburner. TYPICAL THO.

    August 30, 2011 at 2:38 pm | Report abuse |
  6. saltymonkey I'll just leave this here...

    August 30, 2011 at 2:39 pm | Report abuse |
  7. DaveInTexas

    The media (including you, CNN) needs to keep the drama and hype going as long as possible before the event, to keep people watching. Then, they need to hype the aftermath, including a big story about the huricane being over-hyped! People who are complaining about this are the same people who get out of their cars every day and say "See, I didn't need to use that darn seat belt! It did nothing for me!". Better a few days of inconvenience now and then, than to end up drowned in the subway.

    August 30, 2011 at 2:39 pm | Report abuse |
  8. JohnJ

    Weather forecasting is akin to astrology and our federal government is full of overpaid weather employees who collect amazing salaries and huge retirement plans not to mention worthless private companies which have sprung up on the Web (some of these want to charge you a monthly fee for a more "accurate" forecast. haha). You can't predict the future. The problem with these guys is that they convince sheeple to listen to them. I don't depend on the government or a weather channel. I use my common sense.

    August 30, 2011 at 2:39 pm | Report abuse |
  9. Jon

    Let's be frank here, people – Weather is a big, complicated system, and sooner or later it all comes down to educated guesswork no matter what. Personally, I prefer that they overestimate the potential fallout rather than *underestimate* it.

    August 30, 2011 at 2:40 pm | Report abuse |
    • Lee Rutter from Houston

      The media over hyped a lot. The governors and mayors did a real good job at explaining to people of what is to happen... flooding and downed lines... electric service being out. If you are in a low-lying level, get to higher ground. I know, all of this is common sense, but at least the government officials did an outstanding job by not screaming and hollering and going bananas like the news from the east coast channels did.

      August 30, 2011 at 2:49 pm | Report abuse |
  10. USARocks

    @IndiaRocks – whatever u described about america is false and rather attributed to most of indians ... NOTE the "most" and u r big part of it. BTW, why r u trolling here? for what?

    August 30, 2011 at 2:40 pm | Report abuse |
  11. wewatts

    It is amazing the lack of understanding that is displayed on these pages. Some people just do not know what they are talking about.

    August 30, 2011 at 2:42 pm | Report abuse |
  12. Lee Rutter from Houston

    The mayors, governors and our President predicted the storm spot-on, as well as myself and the weather and news people in the Gulf States. The mayors, governors, and President talked about flooding and downed lines, and electric outages which is exactly what happened. Even the weather people on the east coast made stupid remarks. I heard one remark "The hurricane is moving really slow" when the speed was actually 12.5 mph (that's moving fast for a hurricane!). I think the weather people need to tone it down a lot and get your butts off the beach. You folks look like morons leaning to one side screaming at the top of your lungs while people are casually walking by behind you.

    August 30, 2011 at 2:42 pm | Report abuse |
  13. cyclobrown

    the practice for the giant cities is invaluable.

    August 30, 2011 at 2:43 pm | Report abuse |
    • Renee

      Agreed!!! Instead of viewing Irene through pessimistic thoughts ("It was a dud!" "They overreacted!" "We left for nothing!"), consider the optimistic thoughts ("Now we know what we need to do to prepare!" "It could have been worse!")!!!

      August 30, 2011 at 3:01 pm | Report abuse |
  14. Sanity

    I wonder how many people posting here who are complaining that weather forecasters can't predict that path of a hurricane correctly also believe Al Gore when he says people are causing global warming even when he has no supporting data.

    August 30, 2011 at 2:43 pm | Report abuse |
    • John K

      Just because the three day forecast is hard to pin down exactly, doesn't mean that the 50 year forecast isn't rock solid. Remember, "the debate is over". No more discussion.

      August 30, 2011 at 2:50 pm | Report abuse |
    • Ian

      Did you even read the article? They got the path of the hurricane correct, it was the strength of the storm they got wrong. Please read before posting.

      August 30, 2011 at 2:56 pm | Report abuse |
    • Dubben

      "No supporting data"? Have you looked at the data? Obviously science can't predict everything down to the minute detail, but scientific consensus is our best tool, and it strongly favors man-made climate change. It's nice to think like a toddler and believe our actions and irresponsibility are inconsequential, but unfortunately they're not.

      August 30, 2011 at 2:57 pm | Report abuse |
    • ZippyPH

      The debate on climate change IS over, except in the darkest medieval corners of the country. We are close to deciding as a people that it is too large or uncomfortable or expensive to do anything about it.

      August 30, 2011 at 2:59 pm | Report abuse |
    • Sanity

      As I expected. No, we can't predict weather accurately for the next 5 days but we can predict it accurately for the next 50 years. Some of you believers should read the latest study from CERN that was just published in Nature for some real science about the probable cause of climate change. No, it will not satisfy those of you who have an insatiable need to feel guilty for existing.

      August 30, 2011 at 3:07 pm | Report abuse |
    • ZippyPH

      Sorry to belabor this. Your Nature ref. got me interested. This study suggests cosmic rays may have affect clouds and warming (never accept the first study btw)? Nothing about carbon dioxide and warming. I'm not sure why it's better in your mind to deny weight of for for C02 and warming than to just say you would prefer to let Nature takes its course.

      August 30, 2011 at 3:53 pm | Report abuse |
  15. Leela

    So what if the itensity wasn't predicted correctly, this will top Katrina in damage! Have you negative people seen all the damage and lives lost? Give the weather forcasters a break, they have no control over what a hurricane does and how it will behave. That is like trying to control a 2 year old having a tamtrim.

    August 30, 2011 at 2:44 pm | Report abuse |
    • Laurn F.

      Exactly Leela...I'm sure the good people of Vermont would beg to differ with those so quick to render amateur opinions and comments. They got hammered by the rain from Irene.

      August 30, 2011 at 3:00 pm | Report abuse |
    • joedohio49

      If they can't be accurate why aren't they paid accordingly? If I were as accurate in my job I'd be working at Wendy's.

      August 30, 2011 at 3:04 pm | Report abuse |
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