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. W. Ellington

    Its all because the media driving over driving the drama over real news, and this is the reason the storm was blown all out of paportion as to it's real strength. This and not the weather forcasters getting it all wrong.

    August 30, 2011 at 1:38 pm | Report abuse |
    • W. Ellington

      I should proof read better. argh.

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

      The Media over played the storm because they did not want another Katrina incident. Folks in Louisiana and Mississippi didnt take it as a serious storm until it was too late. However, Irene was way too far north to be as big of a threat. The water is simply not warm enough to sustain a real powerful storm. If Irene would have made it into the gulf, that would have been a major storm.

      August 30, 2011 at 2:00 pm | Report abuse |
    • W. Ellington

      Reply to me: (that sounds really odd for some
      You are correct about that, and they still have no idea what her true size could have been. But thank God that High Pressure area was there to prevent it from entering the Gulf of Mexico. But at the sameb time you need to pray for the families that lost loved ones on the east coast. Property for the most part can be replaced, not lives.

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

    don't worry we hate you too

    August 30, 2011 at 1:38 pm | Report abuse |
  3. karek40

    Is anyone else tired of hearing about this storm?

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

      Probably not the people who have loved ones who are still in harms way with flooding. If you are that self-centered to not worry about your fellow man...then dont read the stories. Its not like you are opening a surprise when you click on the story

      August 30, 2011 at 1:42 pm | Report abuse |
  4. W. Ellington

    Its all because the media loves to over drive the drama over real news to drive up ratings, and this is the reason the storm was blown all out of paportion as to it's real strength. This and not the weather forcasters getting it all wrong.
    Everyone in the media knows that drama is what sells.

    August 30, 2011 at 1:40 pm | Report abuse |
  5. Oy

    W. Ellington and rubi...tell that to the people in VT who got flooded out.

    August 30, 2011 at 1:40 pm | Report abuse |
    • W. Ellington

      Oh don't get me wrong, I feel for them there. But the media made this sound like the worst disaster in 100 years and it was not even close. The 40 or so people who lost there lives though is a horrible tragedy. The news doing what they did for this storm just means the next storm on that part of the coast will not be takin as seriously. Cry wolf to often as the story goes.
      But I am NOT be littling what happen to those in those states.

      August 30, 2011 at 1:45 pm | Report abuse |
  6. Grant

    Other possible headlines:
    "We're passing the buck for spending the weekend fearmongering."
    "It's not our fault you have 100 cans of spam now"
    "Come on Irene! We needed at least 100+ deaths"

    August 30, 2011 at 1:40 pm | Report abuse |
  7. historian

    Hype is the name of the game. It also fits the political template.

    August 30, 2011 at 1:41 pm | Report abuse |
  8. Jonathen

    It doesn't take a scientest to tell you a storm is unpredictable. There are many factors out there that can influence a storm that the exports don't even know about.

    Also when storms get manipulated by a certain piece of equipment sitting up in that cold region of alaska, anything is possible.

    August 30, 2011 at 1:42 pm | Report abuse |
  9. uglyfood

    "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'll tell you what – I can predict every storm, just call every single one of them a category 3, and when it turns out to not be severe, you go – hey, its not that bad.

    August 30, 2011 at 1:43 pm | Report abuse |
  10. David

    Out of all the hurricanes I have observed on radar and analyzed myself.. it seems there might be a golden rule that could be so simple most do not see. Once a hurricane makes that northward turn and there is land just to it's west then that hurricane will weaken. Especially if it takes the path like Irene, Isabelle and countless others did. if a hurricane approaches there, it's got land to contend with not only to its west but north (look at that bend in South Carolina through Wilmington and beyond).. I have never seen a hurricane strengthen along a path such as that. Charlie was different because it was a gulf hurricane that turned toward the north but it's counter clockwise motion made its entire west side circulation to take in all that warm water, its right side was over the tropical moist areas of Florida. I know there are other factors to these but if you simplify it.... it can make sense.

    August 30, 2011 at 1:43 pm | Report abuse |
    • David

      A reply to myself... it seems that the direction of the hurricane dictates the dependancy eachquadrant has to sustain itself. when a hurricane takes a more northerly component to direction, its almost as it needs more energy from the northewstern quadrant to feed it....Most of the hurricanes if not all that have a more northward diretion and strengthened were all Golf hurricanes. If we look at the Atlantic, The most devastating hurricanes either took direct aim at land from an east to west direction.. or a northwest Direction. Hugo is a good example of an Northwest direction. Andrew is a good example of an east to west direction.

      August 30, 2011 at 1:48 pm | Report abuse |
    • Steve S

      Thank you, David. You're observations were spot on. I've studied, observed and ridden out many hurricanes. The first hurricane I remember riding out was Carla in 1961. At 7 years old I took a huge interest in learning all I could and that never stopped. As Irene approached, I was hearing all the doom and gloom reports – and I almost had to laugh about the forecast strength. I had concluded 48 hours before landfall that if it took the path predicted it would lose strength rapidly. Problem is, no one is going to listen to anyone without a sheepskin and learned it all from behind a desk. Experience means little to the NHC and it's beginning to show. Best weatherman Houston ever had was Doug Johnson and he wasn't a meteorologist. He was a pilot who learned the weather because he had to.

      August 30, 2011 at 2:08 pm | Report abuse |
  11. Bryan

    Had the right path my tail end!!! They were all wrong on the path. It started out where it was going to hit south Florida. Then they changed the path saying it was going to hit Central/North Florida. Then it was going to hit Georgia, Then it was going to hit South Carolina. By now, we are 24 hours from landfall and they said it would hit North Carolina. Well, that a no brainer because it was already knocking on their doorsteps. These people seriously need to get a real job.

    August 30, 2011 at 1:43 pm | Report abuse |
    • mark in nyc

      i suppose you could do a better job????? i thought not.

      August 30, 2011 at 1:45 pm | Report abuse |
  12. bluemax77

    Dependent on Media hype !! If it wasn’t for disasters, wars, storms and fires the news outlets couldn’t sell airtime...

    August 30, 2011 at 1:44 pm | Report abuse |
  13. cmspsu13

    Thanks for sharing your hate with the group.

    August 30, 2011 at 1:44 pm | Report abuse |
  14. AnAmerican

    Well, at least we don't smell bad...

    August 30, 2011 at 1:44 pm | Report abuse |
    • beef

      hahaha. that's what you think! we smell like cheese to everyone else.

      August 30, 2011 at 2:08 pm | Report abuse |
    • Bugmenot


      August 30, 2011 at 6:47 pm | Report abuse |
  15. John K

    Once this storm passed over the immense spout of hot air emanating from the D.C. area, it never had a chance to restrengthen.

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