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. T-MAN

    Thanks weather guys. Good job on the storm prediction. Perhaps next time people will listen and evacuate or perhaps not stand along a bank of rushing water. Did you read the story about the streaker? OMG, why he wasn't part of the toll, I have no idea.

    August 30, 2011 at 2:04 pm | Report abuse |
  2. joe

    My dog can forecast better.

    August 30, 2011 at 2:04 pm | Report abuse |
  3. Thomas

    Just read a great book called "Isaac's Storm," about the great hurricane of Galveston, TX in the year 1900. Accurately projecting the strength of a hurricane remains a very inexact science because of the variables. Funny how some things, such as the hubris of those who believe we have it all figured out, don't change. However, I appreciate that FEMA and state and local governments were appropriately cautious in their preparations for the hurricane's impact. THAT was the important lesson that needed to be learned.

    August 30, 2011 at 2:05 pm | Report abuse |
  4. AtmosphericScientist

    Coming from an actual atmospheric scientist who studies hurricanes, I watched Chad Myers' performance through this entire ordeal. He is a terrible meteorologist who demonstrated his lack of knowledge of hurricanes by hyping up points about the storm that were simply not true or not possible.

    August 30, 2011 at 2:06 pm | Report abuse |
  5. MikeRI

    Weather operates on the chaos theory. Too many unpredictable variables. I figured that anyone with an ounce of brainpower could realize that. I'd much rather them report what could happen under worst case scenario and plan for that, than to underplay it, and cost lots of people their lives. There's a lot of damage from this storm. I'm really not sure what the big drama is all about.

    August 30, 2011 at 2:06 pm | Report abuse |
  6. Atul Chaudhary

    Obama: "It all Bush's fault." 🙂

    August 30, 2011 at 2:07 pm | Report abuse |
  7. Mark

    10 billion dollar storm....20+ people killed....the state of Vermont is basically a war zone. I see nothing wrong with how the meteorologists forecasted or covered this thing. Being Canadian, what amazes me is how everything is being linked to politics down there. An earthquake and hurricane are supposed to be God's way of telling America to vote Republican? How mentally challenged can people be to swallow this horse****. Hard for anyone to feel sympathy for the USA when you have people like that running for office and Kim Kardashian as "royalty". America...wake u....you are no longer admired. You are ridiculous.

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

      How mentally challenged are you in that you can't recognize when people are trolling for a reaction on these boards? Here's some advice, when you see a post that is right-extreme or left-extreme, take a step back and breath before reacting. many times these people are simply trolling..

      August 30, 2011 at 2:18 pm | Report abuse |
    • djwazu

      I don't know about the rest of the country, but shutting down the subways midday and telling people to leave their homes in NYC was just retarded btw I predicted the stom would be a bust just by looking at the doppler/radar pictures 2 days prior, why couldn't they do it? Makes you wonder wat else they can't do besides reaching into your pockets!

      August 30, 2011 at 2:20 pm | Report abuse |
    • Schmedley

      This is just the media making an issue out of a non-issue again.

      I think forecasters got it right. If you're going to gripe about not being able to predict atmospheric currents that are inherently chaotic and unpredictable, you might as well grip about not being able to predict the stock market.

      You NEVER have 100% certainty about anything. Anyone who thinks they do, are kidding themselves. The forecasters cannot know with certainty how strong the storm will be so it is better to err on the conservative side.

      A category 1 hurricane is still 80+ MPH winds which is nothing to sneeze at. They got it right and whoever wrote this article should be publicly tarred and feathered.

      August 30, 2011 at 2:22 pm | Report abuse |
    • deathwombat

      @richk: He was referring to Michelle Bachmann's "joke" claim that the hurricane was a warning from God. She's not trolling, she's running for president!

      August 30, 2011 at 2:48 pm | Report abuse |
    • W. Ellington

      deathwombat
      Get a life and go troll somewhere else like MSNBC or FOX.

      August 30, 2011 at 3:25 pm | Report abuse |
  8. Larry

    So, what made you think it would intesify? and what happened instead that made it weaken? either the water was cold or hot, the wind blew in a different direction. either the air temp was up or down. this can't be that hard. I bet if we had the same guys that analize baseball stats we might have a fighting chance with weather prediction. Or we need the Math dude from "Numb3rs"!

    August 30, 2011 at 2:09 pm | Report abuse |
    • aaron

      The first two years of a meteorology degree are the same as an engineering degree....... Lots of math.

      August 30, 2011 at 2:23 pm | Report abuse |
    • monolith

      Did u read the article all the way through? Read said plainly that the storm lost alot of strength when it passed over the outer banks, and also from dry air pulled in from neighboring Virginia. He also said that the pressure within the storm stayed very low, meaning it could have gone either way. Perhaps you would have preferred they didn't warn of the potential for a huge storm and had more loss of life than they did?

      August 30, 2011 at 2:26 pm | Report abuse |
  9. rhines

    That’s why they called after females (use to)

    August 30, 2011 at 2:09 pm | Report abuse |
    • Wow

      Wow...at least females can compile a proper sentence.

      August 30, 2011 at 2:17 pm | Report abuse |
  10. Willi

    The technology for weather prediction is far behind. There is no driving force to improve this technology simply because there is no money to be made. Per example, why are we still measuring hurricane intensity based off of sustained eye wind speeds? The total destructive power of storm is really in the amount of energy a storm contains. The categorization of a storm should include at least mass and velocity.

    August 30, 2011 at 2:09 pm | Report abuse |
    • seriously226

      How do you propose they measure mass? Or velocity for that matter – are you going to fly into the storm to measure its velocity?

      August 30, 2011 at 2:35 pm | Report abuse |
  11. Goober Pyle

    Early Saturday, as Irene was moving over North Carolina, Anderson Cooper asked Chad Myers why the hurricane would remain strong and not weaken since it was going over land. In his typical arrogant manner, Myers told Cooper that there wasn't much land, just some barrier islands with a lot of water around them, and this would not affect Irene and it would remain strong and strengthen.

    On Sunday, after Irene had come to New York, Anderson Cooper again asked Chad Myers why Irene was not as powerful as forecast. Myers said, in his typical arrogant manner, because the hurricane had gone over land in North Carolina, and that we all know when a hurricane goes over land it weakens. DId that North Carolina land change sometime between Anderson Cooper's two questions to affect the hurricane differently?

    Forget about the fact that CNN and the other news channels were busy making claims late Saturday that just because Irene weakened, it was still just as dangerous as before, simply so they could keep people tuned in to all the reporters they had stationed in Manhattan despite the fact the winds wre only 30 mph at that point.

    CNN banked on Manhattan being wiped off the planet by Irene. They forgot to put reporters in the many other areas that were really affected by Irene, such as Vermont flooding, North Carolina flooding, etc. But those areas don't have lots of viewers to draw ratings I guess...

    August 30, 2011 at 2:09 pm | Report abuse |
  12. Mike

    Is this really news? Have the editorial staff a CNN never seen a weather forecast that was inaccurate? It is a pity that our media and to some extent our society is fixated on the perfection of others while ignoring the own midjudgments. CNN your decision to make this news was inaccurate.

    August 30, 2011 at 2:09 pm | Report abuse |
  13. CNNotReally

    This was the "STORM OF THE CENTURY", according to CNN. /lol.... what a joke.

    Go back and look at how CNN profiled this storm. – you'd have thought Noah was going to show up with a new Ark.

    Friggin' journalists..... anything to get a buck.

    August 30, 2011 at 2:12 pm | Report abuse |
  14. CNNotGood

    This was the "STORM OF THE CENTURY", according to CNN. /lol.... what a joke.

    Go back and look at how CNN profiled this storm. – you'd have thought Noah was going to show up with a new Ark.

    Friggin' journalists..... anything to get a buck.

    August 30, 2011 at 2:12 pm | Report abuse |
  15. Gumby

    water is too cold in upper north east. does not take a rocket seintist to figure that out. off course it's going to lose strengh. lived all my life in NE and they always get downgraded to tropical storms.

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