Strong Start Increases NOAA’s Confidence for Above-Normal Atlantic Hurricane Season

Contact: Carmeyia Gillis

FOR IMMEDIATE RELEASE

301-763-8000, ext, 7163 Aug. 7, 2008

Strong Start Increases NOAA’s Confidence for Above-Normal Atlantic Hurricane Season

In the August update to the Atlantic hurricane season outlook, NOAA’s Climate Prediction Center has increased the likelihood of an above-normal hurricane season and has raised the total number of named storms and hurricanes that may form. Forecasters attribute this adjustment to atmospheric and oceanic conditions across the Atlantic Basin that favor storm development – combined with the strong early season activity.

NOAA now projects an 85 percent probability of an above-normal season – up from 65 percent in May. The updated outlook includes a 67 percent chance of 14 to 18 named storms, of which seven to 10 are expected to become hurricanes, including three to six major hurricanes of Category 3 strength or higher on the Saffir-Simpson Scale. These ranges encompass the entire season, which ends November 30, and include the five storms that have formed thus far.

In May, the outlook called for 12 to 16 named storms, including six to nine hurricanes and two to five major hurricanes. An average Atlantic hurricane season has 11 named storms, including six hurricanes and two major hurricanes.

“Leading indicators for an above-normal season during 2008 include the continuing multi-decadal signal – atmospheric and oceanic conditions that have spawned increased hurricane activity since 1995 – and the lingering effects of La Niña,” said Gerry Bell, Ph.D., lead seasonal hurricane forecaster at NOAA’s Climate Prediction Center. “Some of these conditions include reduced wind shear, weaker trade winds, an active West African monsoon system, the winds coming off of Africa and warmer-than-average water in the Atlantic Ocean.”

Another indicator favoring an above-normal hurricane season is a very active July, the third most active since 1886. Even so, there is still a 10 percent chance of a near normal season and a five percent chance of a below normal season.

NOAA’s hurricane outlook is a general guide to the expected level of hurricane activity for the entire season. NOAA does not make seasonal landfall predictions since hurricane landfalls are largely determined by the weather patterns in place as a hurricane approaches.

Five named storms have formed already this season. Tropical Storm Arthur affected the Yucatan Peninsula in late May and early June. Bertha was a major hurricane and the longest-lived July storm (July 3-20) on record. Tropical Storm Cristobal skirted the North Carolina coastline. Dolly made landfall as a Category 2 hurricane at South Padre Island, Texas on July 25. And on August 5, Tropical Storm Edouard struck the upper Texas coast.

“It is critical that everyone know the risk for your area, and have a plan to protect yourself, your family and your property, or to evacuate if requested by local emergency managers. Be prepared throughout the remainder of the hurricane season,” Bell said. “Even people who live inland should be prepared for severe weather and flooding from a tropical storm or a hurricane.”

The Atlantic hurricane season includes activity over the Atlantic Ocean, Caribbean Sea and Gulf of Mexico. The peak months of the season are August through October.

NOAA understands and predicts changes in the Earth’s environment, from the depths of the ocean to the surface of the sun, and conserves and manages our coastal and marine resources. Visit http://www.noaa.gov

On the Web:

NOAA’s National Weather Service: http://www.weather.gov

NOAA’s Climate Prediction Center: http://www.cpc.ncep.noaa.gov

Updated 2008 Atlantic Hurricane Outlook:

http://www.cpc.ncep.noaa.gov/products/outlooks/hurricane

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34 thoughts on “Strong Start Increases NOAA’s Confidence for Above-Normal Atlantic Hurricane Season

  1. Did NOAA make the same calls for the 2006 and 2007 seasons? The charts I saw both those season were some of the lowest for storms?

  2. My understanding of hurricanes is limited and I’d like Anthony to correct me, but in addition to the warm water feeding energy and moisture to the storm, the system also requires contrast with a cooler atmosphere. The recent lower troposphere data suggests a cooler atmosphere compared with recent years, so the prediction of more storms seems reasonable.
    I hope the media and politicians are very clear about this. The prediction of increased storm activity cannot be due to global warming.

  3. NOAA understands and predicts changes in the Earth’s environment, from the depths of the ocean to the surface of the sun
    Huh???

  4. Didn’t they predict a strong hurricane season the previous two years?
    Even a broken clock is right twice a day.

  5. Well its nice to be able to change your prediction 1/3 of the way through the season. This reminds me of an old Pogo cartoon. One of the characters became a weatherman and hung up his shingle which said; ” Weather casting – fore and aft”.
    I guess aft-casting is more accurate.

  6. I know, Robert Wood, who whoever wrote that is probably living in a rundown apartment by know, “thawing hot dogs in a kitchen sink”(Simpson’s quote). How dare anyone even REMOTELY suggest the sun has any relevance to Gaia’s health situation!

  7. Is anyone keeping score?
    My sense is that none or nearly none of the hurricane predictors have better track records than a typical psychic, but I freely admit that I may be suffering from confirmation bias and selective memory….
    At least the hurricane center supplies error bars for their five-day outlook track predictions 😉

  8. So this is “news” ??
    So how many times in history has the hurricane count been above “normal” ??
    Can you say “average” ?
    My guess would be 50%, but I’m no Stats expert 🙂

  9. David Segesta (12:19:11) :
    “Well its nice to be able to change your prediction 1/3 of the way through the season. This reminds me of an old Pogo cartoon. One of the characters became a weatherman and hung up his shingle which said; ” Weather casting – fore and aft”.
    “I guess aft-casting is more accurate.”
    Yeah, if they waited until December, they could obtain 100% accuracy. Isn’t more important to get it right, even if you have to wait?

  10. Like my Dad use to say, everyone talks about the weather but nobody does anything about it.
    I wonder what my Dad would think about people today taking this line seriously.

  11. WOW, I looked today and none are anywhere in the Atlantic…….seems like over reaction has once again risen up. I may be wrong, but this looks like a bold statement to me.

  12. Oh yeah, I meant to check the new Klotzbach/Gray forecast issued a couple days ago.
    http://hurricane.atmos.colostate.edu/forecasts/2008/aug2008/aug2008.pdf

    ABSTRACT
    Information obtained through July 2008 indicates that the 2008 Atlantic hurricane season will be much more active than the average of the 1950-2000 seasons. We estimate that the full 2008 Atlantic basin hurricane season will have about 9 hurricanes (average is 5.9), 17 named storms (average is 9.6), 90 named storm days (average is 49.1), 45 hurricane days (average is 24.5), 5 intense (Category 3-4-5) hurricanes (average is 2.3) and 11 intense hurricane days (average is 5.0). The probability of U.S. major hurricane landfall for the remainder of the hurricane season is estimated to be about 130 percent of the long-period average. We expect full-season Atlantic basin Net Tropical Cyclone (NTC) activity in 2008 to be approximately 190 percent of the long-term average. We have raised our seasonal forecast from what was predicted in early April and early June. This is due to a combination of a very active early tropical cyclone season in the deep tropics and more favorable hurricane-enhancing sea surface temperature and sea level pressure patterns in the tropical Atlantic. The primary concern with our current very active seasonal forecast numbers is the continued ocean surface warming in the eastern and central tropical Pacific. Although it seems unlikely at this point, there is a possibility that an El Niño could develop this fall.

    The long-term average is 1950-2000.
    Their forecast is particularly interesting this year as they are using new predictors, as the last couple of years have been a “learning experience.” (Hey, you learn a lot more from mistakes than from getting things right.):

    8. Discussion of 2008 Forecast
    In the 25 years since our CSU forecast team began issuing seasonal hurricane forecasts, we have always tried to make our forecasts as transparent as possible. We have attempted to fully explain just how we made these forecasts and the physical reasons for why we proceeded as we did. When the season was over, we have gone through considerable effort to fully document all the tropical cyclones that occurred and to explain the broader-scale climate features with which they were associated. We have tried to be as honest as we could in discussing our forecast successes and our inevitable forecast failures. We have not been ashamed of our forecast failures. It is the nature of seasonal forecasting to sometimes be wrong. Our only regret would be if we had not given our best effort and did not turn over every stone in the quest for the best possible forecast. In addition, forecast failures drive us to improve our statistical forecast models by accounting for our errors. Our forecast failures of 2006 and 2007 were the impetus to drive us to develop new and improved forecast schemes. All of our statistical models for the 2008 hurricane season are new and contain what we believe to be improved model physics. Anyone who wants to duplicate this early August forecast for the 2008 season or the hindcast statistics for the 1950-2007 seasons can do so through using the NCEP/NCAR reanalysis data which are readily available on the web.

    The next update will be released on September 2nd.

  13. In defense of hurricane predictions (and living in South Florida where we keep a careful eye on these things), in the last two years factors came into play that were not well accounted for in the forecast models. Sound familiar? In 2006 we watched storm after storm form up in the Atlantic, only to get ripped apart by wind shear before they were strong enough to be named. So the ‘cane-counts were much lower than predicted (thank goodness) but the models obviously needed some work on whatever wind shear variables they use.
    Last year we had two Cat 5’s go ashore (unprecedented, I believe). But the models had failed again to adequately account for (1) el Nino, and especially (2) Saharan wind patterns that covered the Atlantic from Africa to the Caribbean with dry air and dust, inhibiting storm formation. Note that the two Cat 5’s developed south of most of this dust.
    Each year the models get tweaked a bit to account for lessons learned in past hurricane seasons, and daily model runs (publicly available on a number of sites) get better each year. The climate modelers might take a lesson from all this.
    Note that now through the end of September is the peak of the season. Also the local weather guys have been describing ENSO and the Atlantic Oscillation accurately for years, especially in regard to hurricanes, and they generally keep us well informed with better information than you get from the national press.
    Oh yeah, a ‘normal’ season is just the historical average.

  14. David Segesta (12:19:11) :
    “Well its nice to be able to change your prediction 1/3 of the way through the season.”
    That seems rather harsh. While I much prefer the Klotzbach/Gray forecasts over NOAA’s because of all the data and description that goes in theirs, the two have similar schedules and people interested in Atlantic Hurricanes and forecasts expect new forecasts.
    While we are 1/3 of the calendar time through the season, June and July typically have very few storms, the five named storms this year make it no surprise that the named storm prediction would go up. I don’t think we’ve had any intense storms yet, but that’s no surprise and probably no impact on that part of the forecast.
    It’s also no surprise that the forecasts are for well above average seasons. Since the AMO flip in the mid 1990s we’ve been in an active period, much like the 1930s and 1950s. In inactive periods, we might have had no storms yet. (Hurricane Andrew was the only big storm of 1992, it formed in mid-August. Hurricane Bonnie formed in mid-September.)
    I figure that there’s 90-95% of the season yet to happen, so I have no trouble with forecast updates. Much of the CSU forecast has sections on “post 1 Aug” or “August only” predictions that don’t fit into press releases and sound bites.
    Research first and then criticize (or improve), please.

  15. “NOAA understands and predicts changes in the Earth’s environment…” This sounds like wishful thinking to me. …”from the depths of the ocean to the surface of the sun” sounds like a commercial. Nobody knows climate like NOAA knows climate.

  16. We shall see what we shall see.
    The last two years were lucky for the East coast and the Gulf. Lower than expected number of storms (though the number may have been inflated with the ‘Tiny Tims’).
    If I remember correctly, we’re in the midst of a 25 (or so) year period of greater tropical activity, so the past two years were decidely not normal in that regard. So the fact that this season has been busier should come as no surprise. Eventually, in another 10 years or so, the activity levels should diminish.

  17. Something has always puzzled me, how did they every know how many hurricanes were out in the Atlantic before satellites? Sure an occasional ship my have found one but it may have sunk.

  18. bob gregg (17:30:25) :

    Something has always puzzled me, how did they every know how many hurricanes were out in the Atlantic before satellites? Sure an occasional ship my have found one but it may have sunk.

    Apparently there have been a lot of ships, but yeah, missed storms are a significant issue in looking at longterm trends. Perhaps even bigger is the uncertainty in knowing the complete track or having a good record of the intensity. Hurricane hunter flights began in the 1940s, but even with them hurricanes far from land weren’t checked, especially those in the eastern Pacific, so the decent history of hurricane intensity is less than 50 years old.
    It’s another one of the big reasons Bill Gray refuses to put any faith in any claims about global warming and hurricane intensity or energy release.
    Even trying to extrapolate from landfalling storms is problematic as some years favor landfalls, some years don’t. That’s one aspect of hurricane prediction people are working on, but it has a ways to go.
    If you really want to go out on a limb, check out http://theweatherwiz.com/Hurricane-FUTURE.htm – it’s a site run by Joe D’Aleo’s high school teacher and is trying to forecast the weather from past analogs. Not a new idea, but an interesting implementation. I haven’t checked out any of the forecasts, but have put it on my list of stuff I’ll don’t expect to get to.

  19. By the way, knowing how sensitive we are to “Hansenized” data, folks should be aware of an ongoing “Atlantic Hurricane Database Re-analysis Project.” It’s spearheaded by Christopher Landsea (one of the authors of the NOAA prediction). When he was a student under Bill Gray, so much historical data was poor or damaged that it caused problems with testing forecasting software. He started this soon after joining NOAA and his team is going through _all_ the data available teasing out typos (fine) and adjusting data (alert! alert!) to come up with a usable data set.
    This is not an exercise in taking quantitative data and adjusting it for local and temporal conditions, it’s more a matter of taking uncertain data and determining what would have been measured if it could have been measured. Except for one detour, they started with 1851 and have worked forward. The exception was to review Hurricane Andrew, then the most costly storm in history, to refine track, landfall, windspeed at landfall, etc. The result was to upgrade landfall from Cat 4 to Cat 5. It’s interesting that even now we don’t have enough equipment or the density to answer some simple questions. Just like the USHCN surface stations, except that the anemometers blow away, especially the ones best sited for the storm at hand.
    All in all, it looks like a big project with a lot of manual labor on a lot of data points.
    http://www.aoml.noaa.gov/hrd/data_sub/re_anal.html

  20. I’ve wondered about the inhibiting effect of previous activity relative to later storms. If storm convection effectively sucks the energy out of the sea surface, could early storms like last year’s Cat 5’s and storms that never gain coherence (such as due to wind shear) and wind up as just large areas of thunderstorms be used as predictors for late season storms? You had Bertha hanging around for a long time, did it exhaust the available energy, so some time would be necessary to rebuild the amount needed to jumpstart the next storm? In other words the number of TC may not be a predictor but convective activity might.

  21. What I’ve noticed is that NOAA is naming any cluster of thunder storms and calling it a ‘tropical’ storm even though it forms well above the tropics. for a time they used the term ‘sub-tropical’ now they just tack the next alphabetical name and give it a reason for alarm and the ratings pimp weather guys just thank them and go live to a shower in Texas.

  22. BarryW (20:29:18) :
    “I’ve wondered about the inhibiting effect of previous activity relative to later storms. If storm convection effectively sucks the energy out of the sea surface, could early storms … be used as predictors for late season storms?”
    I don’t think they’re used as such, but a storm’s passage does leave cooler water in its wake. Both evaporation and mixing of the ocean column are culprits. In the short term, a storm that stalls will be forecasted to weaken due to SST cooling.
    The empirical and analog forecasting Gray & associates use does take that into account indirectly – if the current season looks similar to a previous season, then expectations are that the two will be similar. So any suppression due to activity in the previous system is carried forward into the current season.

  23. A story in Science News is loosely related to hurricanes, so I’ll post it here. It’s more related to incomplete climate models.
    http://www.sciencenews.org/view/generic/id/35023/title/Forecast_Gullywashers says in part:

    Models not accurately predicting intense rains of warmer climate
    Climate simulations are underestimating how often intense rainstorms occur at warm temperatures, new analyses of weather data suggest. If true, the findings indicate that episodes of extremely strong precipitation, usually accompanied by flooding, will strike more often if the global average temperature continues to rise.

    Statistical analyses of the satellite data, to be reported in an upcoming Science, indicate that “very heavy” precipitation episodes — those within the top 10 percent of rainfall totals for each patch of ocean — occurred between two and three times more often than an ensemble of climate simulations suggest.

    Their comment system doesn’t like me today, I tried to add:

    The real world observations are certainly no surprise to weather watchers, especially this summer in New Hampshire! If the models are underestimating rainfall, that implies they overestimate water vapor, the most important greenhouse gas, which then implies their temperature projections are too high.

    My guess is that if the modelers fix that, they’ll increase the CO2 feedback factor since that was set to make the projections match the temperature rise over the last few decades. Or however it is that they set it. At any rate, the result may be a wash for recent temperatures, perhaps a bit of reduction in their projections forward.

  24. I was looking at the hurricane center’s website yesterday, and not only was the Atlantic compleatly empty of cyclonic acction, there wasn’t even an area marked as likely to seed cyclonic acction. So far it seems to me that this has been a quiet hurricane season.

  25. Doug (22:46:30) :
    “What I’ve noticed is that NOAA is naming any cluster of thunder storms and calling it a ‘tropical’ storm even though it forms well above the tropics. for a time they used the term ’sub-tropical’ now they just tack the next alphabetical name …”
    The terms tropical, subtropical, and extratropical refer to a storm’s structure, not to any location along its track. Subtropical storms tend to start as a broad area of thunderstorms linked by a large low pressure area. The Weather Underground has a very good writeup at http://www.wunderground.com/hurricane/subtropical.asp . Subtropical storms can “grow up” into tropical storms, but they can be named before that.
    Subtropical storms that eat up names and never become tropical storms are a bit awkward for the longterm tropical storm forecasts, since the count of named storms no longer matches the count of tropical storms, Gray and co. have groused about that a bit and claim that the NHC has been too quick and inconsistant about assigning names to subtropical storms.

  26. Joe Bastardi, Accuweather’s hurricane capo, has long pointed out that total number of storms, while interesting in the abstract, is not the crucial figure for tropical cyclone impact, except, perhaps, for schools of fish; rather, it is the number and tracks of landfalling storms that is important.
    Is this the year that at least one major hurricane affects the east coast from Hatteras north? Or how about four such storms in a month a la 1954, during the last maturing phase of the AMO? Imagine what the Gang would make of that? Hurricane Carol did to Providence, Rhode Island what Katrina did to New Orleans. The center of Hazel, in October, passed 80 miles west of New York City, but produced a sustained wind at the Battery of 115 mph, still the official record for the city.
    Or how about Hurricane Donna in September of 1960, the only storm on record to produce hurricane conditions onshore in every state from Florida (both coasts) to Maine?
    Deja vu? ‘We have all been there before.’

  27. By the way, once again I have been cheated! Arthur huffed and puffed its way up to 39 mph for a couple of hours wasted the name. I wish I were an Andrew.

  28. ‘So far it seems to me that this has been a quiet hurricane season.’
    But here comes the MJO, just in time for the heart of the season.

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