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. weather people

    if it went from a 3 to a 5, would people be yelling at them for telling people to evacuate and spare even more lives?

    damn if you do, damned if you don't.. i would hate to be a weather person.

    August 30, 2011 at 4:06 pm | Report abuse |
  2. SC

    what? there's not an app for that?

    August 30, 2011 at 4:09 pm | Report abuse |
  3. GonzoG

    At last count 24 people died and $10 billion in damages. I HOPE the death count doesn't go up, but I'll be shocked if the damage cost doesn't.

    What part of this was NOT a major storm? Just because downtown Manhattan didn't get swept into NY harbor, doesn't mean the NWS over sold it.


    August 30, 2011 at 4:11 pm | Report abuse |
    • mdubbs

      Well didn't you know? NYC is the center of the universe...

      Please, it's a dirty city, just like any other city in the world (and I've been to quite a few of them).

      August 30, 2011 at 4:34 pm | Report abuse |
    • Wildknife

      to answer your question... it was a cat 1... which is the weakest... how is a storm "major" when it was at the lowest level of it's own rating.. and honestly.. anybody with a little bit of education could have for seen it making landfall as a cat 1.. the temp of the seas were too low to fuel it.. the sea's temp keeps getting cooler the further north it got.. and honestly.. I feel this is all just a way to make people "scared" and feel "terror"

      I honestly wanna see this "10 bil" of damage...

      did any tornado's drop? 50 square miles of flooding anywhere? whats the population of the eastern US.. around 200 mil? and only 26 dead.. dont 26 people die anyways within a 3 day span?

      Look at the facts and dont be in a state of "terror" whenever you do not have all the facts...

      August 30, 2011 at 4:35 pm | Report abuse |
    • truth hurts

      over 100 people died in Joplin alone..flooding, anf damage happens without it being a huricane...regular thunderstorms can do that. To tell the truth the media did overhype things..they kept refering to 911 to scare people, they kept saying words like eerie and scarry, they made reporters stand in sweage..they even went out of the way to make computer simulated images of doomsday...Bauchmann got on stage saying that her god is punishing obama..puhleese smh..i wast fooled for a second that this was the storm of the decade like the weather people overhyped it to be. I find it hillarious that the weather people now says it was the size of the storn they were promoting was huge, and not the strength..i call BS on them..there has been regular thunderstorms that covered many states that they never hyped up as much as this one...all you people who were fooled just need to admitt it and move on..denial is not going to make the fact you were fooled by the media go away.

      August 30, 2011 at 5:06 pm | Report abuse |
  4. truth hurts

    weather people nowdays cant predict 6 o' clock at 5:30 let alone the weather..I blame it on the decline of the education system.

    August 30, 2011 at 4:12 pm | Report abuse |
    • ThatGuyBill

      your an idiot

      August 30, 2011 at 4:26 pm | Report abuse |
    • Kendall

      *You're* an idiot.

      August 30, 2011 at 4:32 pm | Report abuse |
    • truth hurts

      No..YOU'RE the idiot...LOL

      August 30, 2011 at 4:52 pm | Report abuse |
  5. flyingram

    Luigi –

    Your comparison between CNN and the postings on this discussion area make a good point.

    However, your logic appears flawed if only because you are comparing a world-wide news organization whose reputation rises and falls with credible reporting and veracity – with – what can only be called several "far out" comments by individual people. The latter gets read only by a few people, whereas the exposure of CNN misreporting reaches millions.

    Surely, you are not serious about comparing the two. Are you?

    August 30, 2011 at 4:13 pm | Report abuse |
  6. Vex

    Better to be prepared for the worst, than to be caught off guard.

    August 30, 2011 at 4:14 pm | Report abuse |
  7. Cindy from NC

    We have become so desensatized. catastrophic movies and extrem major disasters. ave made us think this was nothing when in reality it was major and it was big. I guess if they had a telethon, might make you some of you feel better that this was a major diaster.
    Better to be safe than sorry and if you think it too much hype, turn the channel cause that hypes saved some lives.

    August 30, 2011 at 4:14 pm | Report abuse |
  8. Jim

    I think next time the weather man should just say "It may be storng, it may weaken take you're chances and say in a area that could get hit hard or leave. Its up to you". If hundreds or thousands of people died instead of the 20 or so then people would be yelling to kill all the weather men. Give them a break, we got lucky and it weakend, be thankful...

    August 30, 2011 at 4:16 pm | Report abuse |
  9. TampaMel

    As the families of the people who died or the people in Vermont if the storm was nothing

    August 30, 2011 at 4:17 pm | Report abuse |
  10. Renato

    I agree the predictions can't be 100% be accurate. However in this case the hurricane seemed to have the winds slowing down compared to the initial predictions. Even at that point the predictions for the next days were not corrected to reflect the proportions of decreasing winds. Saying you predict at point A in the next 24 hours – 120 mph and at point B 110 mph. Following day storm gets to the point A with 100 mph Prediction for point B was 100 mph instead of 92 mph. On top of that when everyone realized the predictions where way off, CNN continued to cover a C1 hurricane as a C3. (24 hours coverage) Higher ratings these days...certainly YES...higher credibility for the station...certainly NO.

    August 30, 2011 at 4:18 pm | Report abuse |
  11. Marilyn Coffelt

    Regarding Hurricane: I don't believe the meterologists missed it, I believe it was a level 3! I believe people prayed
    for it to dissipate and GOD answered prayer, it would have been alot worse had it been a level 3. "Remember" people
    prayer changes things!

    August 30, 2011 at 4:18 pm | Report abuse |
    • Russ

      You're joking right? About the praying? Pretty sure praying had nothing to do with Irene weakening. As you would know if you read the article it weakened because of the movement over land and the dryer air mass over Virginia and Maryland.

      August 30, 2011 at 4:42 pm | Report abuse |
  12. Jaz

    This article is ridiculous. Lives were lost and damage was incurred. Shouldn't we be glad that forecasters prepared us for the worst and that it did not happen? They are called FORECASTERS: they are trying to figure out what will happen in the future. C'mon people... get a grip! Personally, I'm glad they were wrong. At least my family was prepared.

    August 30, 2011 at 4:20 pm | Report abuse |
  13. GilVelasquez

    It just seems like too long to gather the information between the air flights over these storms. In todays age you would think that the information could be retrieved and evaluated faster. 4 hours waiting between flights is way too long.....just saying.

    August 30, 2011 at 4:20 pm | Report abuse |
  14. Geest

    I can only hope that the lack of trust in hurricane forecasting and calls for the dissolution of FEMA and NOAA among Southern Red States leads to more death and destruction for those idiots.

    August 30, 2011 at 4:21 pm | Report abuse |
    • CK

      Unbelievable to wish death on anyone.

      August 30, 2011 at 4:22 pm | Report abuse |
    • Twilighttrail

      And your wish for more death makes you better how?

      August 30, 2011 at 4:31 pm | Report abuse |
    • mdubbs

      New Yorkers are the ones complaining. What's the saying, "Check yourself before you wreck yourself." Moron...

      August 30, 2011 at 4:36 pm | Report abuse |
  15. flyingram

    For the record, India, as of 2010, more than 37% of India’s population of 1.35 billion still lives below the poverty line.

    In point of fact, by both practice and cultural norms, India has long since held the "distinction" as having more poor people than any other nation on the face of the earth. In rural areas, the conditions of many villages and familes border on chronic desperation. The howls of protest that rose when "Slum Dog Millionaire" was viewed – showed children picking through garbage and suffered from significant malnutrition.

    I venture a guess that not too many people are waiting in line for resident visas to go and live there.

    August 30, 2011 at 4:21 pm | Report abuse |
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