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 P

    Here's the issue from an Engineers/Viewers perspective.

    By its nature CNN must promote (read, sensationalize) whatever story they are reporting on. This rolls up even to their weather/science/medical stories. It's ALL about ratings. CNN/Fox, etc. etc have all the same mantra. They are in the business of dread. They purposely carry us to the extreme of just about every story. Why do you think they call it the "Situation Room?" DO you really think there is always a "Situation?" Of course not. But it's always The End of the World as We Know It, on just about every story.

    August 30, 2011 at 7:45 pm | Report abuse |
  2. Mad Hatter

    Well hurricane katia is on her way towards us. So all you whiners might get a chance to have one worse than irene. It is better to be safe. So get prepared as hurricane season isn't over.

    August 30, 2011 at 7:46 pm | Report abuse |
  3. Will

    I'd rather have the hurricane weaker then expected over stronger then expected any day.

    August 30, 2011 at 7:49 pm | Report abuse |
    • Really???

      The roofers finished repairs from the 2 ft wide oak tree that fell on my house 5 weeks ago just hours before Irene visited us. I am so happy I did not have to call my insurance agent to report more damage! I would much rather prepare for the worst & receive something better any day. Thanks to the warning, we hurried our repairs & it prevented major structural damage to our home during the storm. We would have had just a tarp between us & the storm without those advisories. Who cares if the news is spread by people without a degree, as long as it comes from reputable scientific sources. Just be grateful we are getting more warning in this century than in previous ones. Modern forecasting has lessened the death toll for these monster storms considerably, but hurricanes are the essence of unpredictability. I think I will just heave a sigh of relief. Then I'll continue with the repairs from the oak that was weakened from last winter's record blizzard.

      August 30, 2011 at 11:04 pm | Report abuse |
  4. Jeltez42

    Let me say I am beyond joyous that Irene fizzled. I have some real issues with how CNN and the Weather Channel bombed on covering hurricane Irene. Even the NHC track was wrong for the first several days. What really did it for me was when CNN turned their weather readers loose to make forecast predictions. Jacqui Jeras is not a meteorologist. She is a journalism major that has a AMS/NWA broadcast seal, aka a certified weather reader. These people get their forecasts from NWS, Weather Channel, or Accuweather. Sure she is free to opine, but Chad Meyers is the one with the meteorology degree.

    August 30, 2011 at 8:15 pm | Report abuse |
  5. the prophet

    Hello to my readers thanks always for commenting to my blogs, we are now entering a crucial timeline where states and governments are falling to save the people and themselves. There are going to be more catastrophes coming our way. All I can tell you is we will die in massive numbers and no government will help the people.

    August 30, 2011 at 8:36 pm | Report abuse |
  6. nina valentino

    to TR Scientist.....sounds like you could do a better job....apply for the job or something. you are too egotistical. weather is predictable? boy are you naive. are you saying that dopplers and radars are completely accurate or it was read wrong? the thing is that there had to be enough time to prepare for an evacuation so to prevent a catastrophe. i watched the whole thing from start to finish i was in the path of irene and i wanted to be prepared were you in the path or an observer from afar? how many minutes apart from a reading on the doppler or radar...they wanted to avoid what happend from katrina thats why it was imperative for an evacuation. my god..so many opinions and so many haters ..society is cruel. i think losing even one person in a climate condition is terrible let alone more. the city that doesnt sleep is all mad and i think its ungrateful and plain rude because an evacuation was in affect and interupted their busy lives...wow they would have complained if it struck and werent evacuated there is no making that cities population happy always something to complain about i guess.....oh well i am happy for the prediction it made me aware and to prepare and i was....god just gave us all a little break.

    August 30, 2011 at 9:43 pm | Report abuse |
  7. nina valentino

    to TR Scientist.....sounds like you could do a better job....apply for the job or something. you are too egotistical. weather is predictable? boy are you naive. are you saying that dopplers and radars are completely accurate or it was read wrong? the thing is that there had to be enough time to prepare for an evacuation so to prevent a catastrophe. i watched the whole thing from start to finish i was in the path of irene and i wanted to be prepared were you in the path or an observer from afar? how many minutes apart from a reading on the doppler or radar...they wanted to avoid what happend from katrina thats why it was imperative for an evacuation. my god.. i think losing even one person in a climate condition is terrible let alone more. the city that doesnt sleep is all mad and i think its ungrateful and plain rude because an evacuation was in affect and interupted their busy lives...wow they would have complained if it struck and werent evacuated there is no making that cities population happy always something to complain about i guess.....oh well i am happy for the prediction it made me aware and to prepare and i was....

    August 30, 2011 at 9:45 pm | Report abuse |
  8. joann

    I,say it's,better to be safe,than sorry.Look,at the lives lost in the storm,so far.The,weather,service did what,they thought was the RIGHT THING,to do.So,blame them. JoAnn Bartholomew

    August 30, 2011 at 10:21 pm | Report abuse |
  9. Tom

    So they are complaining beacuse the hurricane was too weak?!?!

    Apparently not enough people died to satisfy them???

    What is wrong with people these days???

    If you think meteorologists "failed" because "only" ~40 people died, then how many people needed to die for you to be satisfied with the meteorologists???

    August 30, 2011 at 11:10 pm | Report abuse |
  10. Kerry Dean

    Kerry Dean Teverbaugh This is insane, all who say it was a bust should pick up the damage bill and attend those 30-40 funerals. Shame on the you. The storm was off by 10 to 15 mph, This is a discussing blog..
    kerrydeanweather@hotmail.com
    kerry

    August 30, 2011 at 11:18 pm | Report abuse |
  11. Rick James

    I'm Rick James.

    August 31, 2011 at 12:34 am | Report abuse |
  12. bekamu

    The Lord God Almighty sent the wind and the dry air to weaken the deadly storm. To Him be all the glory!

    August 31, 2011 at 2:32 am | Report abuse |
  13. Richard Prior

    My life was put seriously at risk twice in my life by failure to forecast storms. 18 people died in the first incident & 15 in the second.

    1. In October '87, I found myself driving on a Highway in the early hours of the morning facing crosswinds in excess of 120 mph – with flying trees blown across in front of me. At the time, did not realise the level of the seriousness of the situation, but next morning, found the village where I lived cut off from the outside world with over 200 trees down across access roads to the community, and a lady neighbour had died when her chimney crashed through her roof into her bedroom.

    http://en.wikipedia.org/wiki/Great_Storm_of_1987
    & http://en.wikipedia.org/wiki/Michael_Fish

    2. As a crew member in the 1979 Fastnet Ocean Race. Light to moderate winds were forecast – BUT the aftermath of the storm created the largest peacetime rescue since the end of the 2nd World War.

    http://en.wikipedia.org/wiki/1979_Fastnet_race

    The Message – Stop complaining when the weather forecasters misjudge the strength of a storm – just be grateful for the warning.

    August 31, 2011 at 3:38 am | Report abuse |
  14. Richard Prior

    Talk about getting it wrong.

    See this video – http://www.youtube.com/watch?v=eKPQLl5rupg&NR=1

    125mph winds destroyed swathes of South East England in 1987.
    Listen to the Weather forecast on the Video & then consider that you are lucky to have any storm forecast – however inaccurate.

    August 31, 2011 at 3:54 am | Report abuse |
  15. Betty

    I have a great answer for how/why Irene weakened - because there were people in North Carolina, and all along the East Coast I'm sure, praying that it would weaken and/or more further east in the ocean. God answered our prayers. No computer models can predict the power of our almighty God.

    August 31, 2011 at 10:45 am | Report abuse |
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