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. bassmaster22

    Any chance to whip out the dramatic music and scary graphics, right? The real storm was the media coverage. I always get a laugh when anchor people spend 95% interviewing each other rather than experts with degrees. Not to mention, they couldn't get through an entire press conference without cutting back to an anchor for comment and rehash. These 24 hour news channels have an hour of material that they make last all day.

    August 30, 2011 at 1:46 pm | Report abuse |
  2. VistaPoint

    Forecasters did a great job and we should all be thankful. They were able to predict the hurricane days in advance and gave us all an opportunity to be prepared. They predict the route very accurately, even though the hurricane did not carry the same punch, for which we should be thankful. For those families who lost loved ones or lost homes and businesses, it does not matter whether the hurricane is category 4 or category 1; they have lost a lot. So for all those folks who express disappointment with the forecaster because the hurricane did not turn in category 4, please be thankful, because there is ral pain involved in calamities..

    August 30, 2011 at 1:46 pm | Report abuse |
  3. Dave

    actually, the NOAA said NY had a 8% chance or less of being hit with hurricane conditions TWO DAYS before landfall. I'd say they were accurate.

    August 30, 2011 at 1:46 pm | Report abuse |
  4. Oliver

    By concocting headlines like this CNN undermines the credibility of science. It is already amazing that they got the path so accurately. It was clearly said that the intensity could fluctuate, so it is just insulting to the people doing the science to say that they got it wrong. There is ALWAYS a margin of error. We should be thankful that the forecasts allowed many lives to be saved. It is always better to overstate your predictions to make people worry more and do more to save their lives than even to estimate exactly or underestimate what's gonna happen. If the forecast had been exactly right, probably a lot more people would have died because they would have thought danger to be less.

    So please, CNN, for once try to measure the social impact of your headlines. You are not just an observer, you are participant and you change things by the way you report, so you have a huge responsibility to the people. If you don't realize that, you are putting people's lives at danger (and that is only to say the least).

    August 30, 2011 at 1:47 pm | Report abuse |
    • W. Ellington

      Again it is a news agency driving drama. Such is the headline of this story. All of them, MSNBC, CBS, CNN, ABC, NBC and FOX should be ashamed of themselves.

      August 30, 2011 at 1:54 pm | Report abuse |
    • Ricke1949

      Predictions are predictions. The definition of science is so broad there is economic science. Science is not gospel and can be messy. Global warming has never be proved to be caused by humans considering all the evidence and evolution fails when you factor in all the matter of the universe, probabilities and time according to the late Sir Hoyle by no means a creationist. Rejoice in benefits but remain skeptical of flat earth theories.

      August 30, 2011 at 1:55 pm | Report abuse |
    • Ahoy

      Science can never spare humanity from God's coming Judgment. We may be able to observe the "wonders" of the world, but we will never be able to hide from He, who created it. And while I agree that CNN needs to stop posting sensationalist type headlines, I'm sure they really don't give a $h!+ what people think.

      Cheers mate!

      August 30, 2011 at 1:58 pm | Report abuse |
  5. walker430

    Just because it was a category 1 not 3 doesnt mean it still didnt cause significant damage! The path should be the biggest concern, not the intensity. And they got that accurate, almost to the mile. In my opinion forecasters did great. Science isnt always 100% and is always improving. And to those who are "tired" of hearing about the storm...obviously you weren't in it and weren't impacted. To those of us who were, we are STILL picking up the suck it up buttercup. If you dont want to hear about it, dont read the articles and mute your TV when it comes on.

    August 30, 2011 at 1:47 pm | Report abuse |
    • Feast of Beast

      Indeed, the forecasters did do a good job. Most impressive, considering all the variables that have to be considered.

      August 30, 2011 at 1:55 pm | Report abuse |
  6. Will

    I hope everyone on the East Coast is doing better, I sincerely do. I live in NOLA, so we know about hurricanes. But how is the marsh fire in NO East not national news right now. The entire NOLA area is cloaked in smoke, we are breathing this even indoors, can't escape it at work or home. Oh that's right, nobody gives a crap about us down here, but once something hits the East Coast...Oh my God!

    August 30, 2011 at 1:48 pm | Report abuse |
  7. Mark

    This is a great article because the next time they are right everyone is going to be sitting at home thinking these guys are always off, and then it is going to "Oh *#*(@()!"

    Do we have to lose another 2K+ people again to remind people that it is "better to be safe than sorry."?

    August 30, 2011 at 1:48 pm | Report abuse |
  8. Taxpayer

    Because NOAA hypes every storm to keep their bloated budget intact. Every indication showed this storm was at least a category lower from Recon (why two planes) and sat photos but in order to show how much they are needed they hype this storm and name storms that showed not even be named just so they can show a large number of named storms.This will help them justify more computers planes and executive salaries.
    Just marketing fishing for dollars

    August 30, 2011 at 1:48 pm | Report abuse |
  9. Joe

    Everyone in the southern US knew it wouldn't hit the mid-Atlantic region as the advertised "Category 3." A hurricane will always lose speed when it hits cold water. Hitting NC first also severely decreased the speed. It didn't take Al Roker for this to be news. The only thing that's sad is New Yorker's complaining about missing any action. No power for 2 weeks isn't very fun.

    August 30, 2011 at 1:48 pm | Report abuse |
  10. Gloria

    Look, Irene was not a mild storm; it wreaked a lot of havoc, caused fatalities, and the cost in damages is in the billions. I've heard weathermen state numerous times, that the outlook is this or that, at a specific time, but it could all change. The folks who complain about evacuations are crazy! Be thankful we have the technology we do have now. Many more lives would be lost annually were it not for the forecasters and their instruments/equipment.

    August 30, 2011 at 1:49 pm | Report abuse |
  11. flyingram

    Geeze, India –

    Tell us how you really feel! You are in a distinct minority.

    For everyone except India:

    For all the blemishes that America has – the America haters are provably wrong. Applications for permanent visas to come and live here are at an all time high. People line up at embassies and consulates around the world just to get in line to come to this wonderful place. To the best of my knowledge, that does not happen with other nations.

    maddening as some of our faults might be, to the dismay of India and others who run the country down, America has always been and still is that shining light on the hill.

    August 30, 2011 at 1:49 pm | Report abuse |
    • Rob

      you just provided the PERFECT example of the effects of propaganda....the best countries in the world often keep their mouths shut about it because they don't want the flood of people...Best education, NOT US....happiest population, NOT US...lowest crime, NOT economy, NOT US....job availability, NOT US...

      August 30, 2011 at 1:53 pm | Report abuse |
    • Mike

      >>Applications for permanent visas to come and live here are at an all time high.<<

      World population is at an all-time high. How many of those applications were accepted?

      August 30, 2011 at 5:51 pm | Report abuse |
  12. Marilyn Coffelt

    I beilieve the weather men were accurate, its just people started praying that the intensity would dimenish and GOD
    answered prayer and it went down to a 1 instead of a 3!!!

    August 30, 2011 at 1:49 pm | Report abuse |
    • Aimer

      You really think, Marilyn? What do you say, then, for the storms that DO come in as a Category 3 or more. Do you think God just ignores the prayers of the people in the path of those storms? Do you think God ignored the prayers of the 40+ people who died due to Irene? Do you think God heard the prayers of the hundreds who are now homeless? If God came through, as you say, and answered prayers and downgraded the storm, where was he in all these other cases?
      'Sorry, but I think you're a little off.

      August 30, 2011 at 3:09 pm | Report abuse |
  13. sideview64

    The public has to stop expecting miraculous forecasts. The forecasters have to admit that all they can do is make informed guesses. Satellites and doppler radar do not trump the power and unpredictability of nature. As for the press, its behavior is too often guided by profit and self-interest, and its hyperbolic weather reporting is frankly irresponsible, if not criminal. Stick to NOAA and Environment Canada for forecasts, and use common sense.

    August 30, 2011 at 1:49 pm | Report abuse |
  14. G

    I predicted the outcome wasn't going to be as big of a deal as they were expecting. The weather channel as well as CNN relies on ratings so.. If they can keep a captive audience they'll sacrifice their credibility.

    August 30, 2011 at 1:49 pm | Report abuse |
    • Elaine

      If you think that the storm wasn't a big deal or was overhyped, I invite you to come here to Vermont, where entire towns were destroyed and there are still plenty of people missing and there is monumental damage to clean up. Of course, as we have a lower population and no professional sports teams or major celebrity hotspots, it will be a while before anyone notices our plight, especially considering the number of people who seem to forget we are even a state.

      August 30, 2011 at 1:57 pm | Report abuse |
  15. Lance

    Given the difficulty in predicting hurricane intensity and path, let alone localized weather patterns – how far off do you think long-term climate forecasts might be, given there are even MORE mechaninations at work?

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