Hurricane Season: How to Read Forecasts, Stay Safe

Dr. Richard J. Pasch, Senior Hurricane Specialist at the National Hurricane Center in Miami, was online Tuesday, May 22 at 1 p.m. ET to take questions on the 2007 Atlantic Hurricane Forecast and tell readers how to read the center's weather reports and prepare for the season.

Coasts Brace for a Busy Hurricane Season (AP, May 22)

The transcript follows.

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Richard J. Pasch: Hello everyone, this is Richard Pasch, Senior Hurricane Specialist at the National Hurricane Center and a member of the seasonal forecast team.

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Washington, D.C.: How likely are we to get a Hurricane Isabel-type storm this year? Or stronger? We've been dodging both blizzards and hurricanes, so I'm wondering if we have a bull's-eye on us this time around.

Richard J. Pasch: Even though we are giving a seasonal outlook for the overall activity, i.e. number of hurricanes, etc., we are not specifying which localities, if any, will be impacted. We do not believe the science has advanced enough to allow any skill in predicting seasonal landfall locations.

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Clifton, Va.: Who is the reader to believe with hurricane forecasts we have yours, the University of Colorado, North Carolina State University and AccuWeather.com? NC State has proven the most accurate over the years. Any years analogous to 2007? What about activity in previous years after the end of an El Nino pattern? Winters are so much easier -- my collies can predict how bad the winter will be by how heavy their coats are! And yeah, they are more accurate than any weather forecaster!

Richard J. Pasch: I think that all of these forecasts have demonstrated some skill in predicting hurricane activity. In fact, all of us should acknowledge Professor Gray at Colorado State University for his pioneering research on seasonal forecasts back in the early- to mid-1980s.

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Pittsburgh: As it turns out, the hurricane forecast for this year has suddenly become very important to me -- we just found out that my husband got the great new job he wanted and we therefore will be moving to Tampa in mid- to late-August. We will be buying a house there, so I want to know what we should be looking for in terms of insurance coverage that would cover losses or damage from a hurricane.

Richard J. Pasch: One of the things we always add as a caveat to our seasonal outlook is that residents of the coast always should be prepared for a hurricane strike in any year regardless of the overall level of predicted activity. Therefore, becuase you will be moving to a location that is hurricane-prone, you should make sure you have adequate homeowner's insurance coverage.

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Alexandria, Va.: Thank you for taking our questions. In addition to being a busier than normal season, do you foresee more intense storms than normal? Can this be modeled and predicted?

Richard J. Pasch: Overall, yes. And we are predicting an above-average number of major hurricanes (max. winds 111 mph or greater) this year -- three to five.

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washingtonpost.com: How exactly is the intensity of a hurricane season predicted? What factors go into the forecast?

Richard J. Pasch: We take into consideration sea surface temperature patterns in both the tropical Atlantic and equatorial eastern Pacific. An important factor is the ongoing multi-decadal cycle of active Atlantic hurricane seasons that we have been experiencing since 1995. In fact, because of this cycle, we have seen above average activity in every year since 1995 -- with the exceptions of the El Nino years of 1997, 2002 and 2006. So it is important to monitor the status of El Nino/La Nina to make the forecast. Although it is difficult to forecast these conditions, it appears unlikely that we will have the inhibiting effects of an El Nino this season. That is one of the main reasons we are predicting an active year.

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Washington, D.C.: When was the last time the Atlantic hurricane forecast did not call for a number of storms "above average?" And how often do the predictions prove accurate?

Richard J. Pasch: It is true that we almost always predicted an above average season for all the years we have been doing this forecast, i.e. since 1998. However, the fact is that we recognized that we have been in an ongoing multi-decadal period of above-average activity since 1995. The years we have overpredicted all have been associated with generally unanticipated El Nino events, which tend to suppress Atlantic hurricane development.

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Providence, R.I.: I'm getting married Sept. 30 in Newport, R.I. Should I purchase hurricane insurance?

Richard J. Pasch: The probability of a hurricane strike in any one location on any given day is extremely low. So you are probably safe without buying "event insurance." That is not an iron-clad promise, however.

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washingtonpost.com: You say El Nino event suppress the Atlantic hurricane season -- could you explain how the phenomena interact?

Richard J. Pasch: It is theorized that El Nino transfers heat to the tropical Pacific atmosphere and sets up a downstream "teleconnection," which produces greater vertical shear over the tropical Atlantic basin. This shear has a suppressing influence on hurricane formation.

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Alexandria, Va.: The multi-decadal cycle you mention -- how far are we into it and how long does it last?

Richard J. Pasch: There is no definite answer to this question, but it could last as long as 30 years from its start (1995).

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Washington, D.C.: How much do human-induced atmospheric warming theories, directly or indirectly, factor into your outlook models?

Richard J. Pasch: We thus far have not included these theories directly into our forecasts. However, sea surface temperature patterns are used as a predictor for our forecasts, irrespective of its cause.

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washingtonpost.com: What sorts of precautions do people living a ways inland, such as in the District of Columbia, need to take for Hurricane season? Do inland populations need to read forecasts differently than coastal ones?

Richard J. Pasch: Unfortunately, the District of Columbia is still vulnerable to several hurricane hazards, such as storm surge associated with the tidal Potomac, freshwater flooding and high winds. I would advise that you read the forecasts along the immediate coastline (i.e. don't focus on the exact track/timing/intensity forecast) and be aware of your particular vulnerability.

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Washington, D.C.: Last year NOAA also predicted a busy hurricane season, but the opposite occurred. Why? And how confident are forecasters that this year's forecast is likely to be accurate?

Richard J. Pasch: Yes, it is true that we overpredicted the level of activity in 2006. The problem was that we had the sudden onset of El Nino just before the historically active part of the season. That was not anticipated. Admittedly, the El Nino/La Nina events are difficult to forecast, but we feel that based on the evolution of the tropical Pacific so far this year, it is not likely that we will see the recurrence of El Nino this year.

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Atlanta: In recent years, storms that reached category five status out in the Atlantic Ocean and Gulf of Mexico have dissipated -- some before making landfall. I know hurricanes lose strength over land, but how does just the approach of landfall affect the behavior of hurricanes?

Richard J. Pasch: It is true that several very strong hurricanes have lost strength just prior to landfall in the past few years -- Katrina and Rita come to mind as examples. Those hurricanes weakened because of a combination of factors, but the approach to land was not likely one of those factors. Conditions in the ocean and atmosphere are far more important for intensity changes.

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Wilmington, N.C.: Thanks for taking my question. As a coastal resident, how does the forecast compare to other years? We weathered Charley and Ophelia with little to no damage. But does the forecast mean that we should be expecting hurricanes like Fran, Floyd or Bertha this season?

Richard J. Pasch: As I have pointed out in some of my other responses, our seasonal outlook is not a forecast of landfall(s) in the U.S. this year. We hope that coastal residents will be prepared for a hurricane every year regardless of the expected amount of overall activity.

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Fort Stewart, Ga.: Do you go into the probabilities of hurricanes hitting for other parts of the coast besides Texas and Florida? I moved to southeast Georgia in late 2005 and it seems that for many years hurricanes have bypassed Georgia, hitting either Florida or North Carolina. Is this likely to remain true?

Richard J. Pasch: We have not been providing the probabilities for hurricanes hitting any part of the coast. You may be thinking of Professor Gray's landfall probabilities.

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What's your record?: Okay, I'm a skeptic. I don't think you can predict this any better than a chimp with some tarot cards (see 2006). But I'm willing to be convinced with statistics. How have you done in the last ten years? Given that the range of possibilities is pretty narrow for both hurricanes and landfalls (0-20) and that the likely range is even smaller, the chimp could do pretty well with those parameters.

Richard J. Pasch: It's good to be skeptical about seasonal forecasts. While we attempt to make our best estimate every year, obviously we have much to learn. That is why you need to have a hurricane preparedness plan in place at the start of every season if you live anywhere along or near the coast from Texas to Maine!

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washingtonpost.com: Can you go over some basic preparation tips -- what sorts of things people need to have on hand, etc.?

Richard J. Pasch: Here's a web link with some useful tips.

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Silver Spring, Md.: Dr. Pasch, thanks for taking my question. Do you believe your office has adequate funding to do its job? I read just this week that the director of the National Hurricane Center expressed his belief that the government is wasting millions of dollars on advertising while shortchanging his hurricane forecasters' budget.

washingtonpost.com: Hurricane Chief: NOAA Wasted Millions (AP, May 17)

Richard J. Pasch: I would rather not answer the question about our (the hurricane forecasters') budget. But I could say that it is my personal opinion that the level of funding for hurricane research is inadequate, and such research often pays dividends by providing us with better tools to predict hurricanes.

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Vienna, Va.: Why have so-called "seeding" operations from aircraft stopped? The first ones were done right after World War II, and showed great promise in lessening wind speeds and storm intensity. Only a slight drop in average wind speed, especially close to the eye wall, could have prevented some of the damage that Katrina did. We had such a great potential for cutting down on storm damage ... why on earth was it stopped? It just doesn't make sense.

Richard J. Pasch: Unfortunately, research has shown that the seeding of hurricanes has no impact in modifying the intensity of these storms. What was formerly perceived to be an impact was subsequently shown to be merely a natural variation (e.g. eye wall cycles) in the inner core structure that led to the intensity changes. Indeed the natural decay of Katrina's eye wall was part of the reason the devastation was spread out over such a large area.

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Ft Lauderdale, Fla.: As a longtime South Floridian, I can't thank you and your cohorts enough for all that you do. My question -- recently on the NHC Web site I saw the paper regarding estimated annual intervals between major storm events at various points on the U.S. coast. I'm curious how you arrived at intervals of 40-50-60 years for the VA-MD-DE coast when you say that the last major storm occurred prior to 1850? Obviously the anticipated interval isn't based on weather history, so what is it based on? Thanks!

Richard J. Pasch: You are correct, that isn't based merely on the storm record. It also takes into account computer simulations of many years of possible tracks based on the record that we do have -- which provides a more stable and reliable statistic.

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Richard J. Pasch: Okay, thank all of you for your interest. And, in spite of our seasonal outlook, let's hope you don't hear much from me this season!

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