| The 2008 Atlantic hurricane season is underway and every major forecast is calling for an active season from “average” (which still anticipates six hurricanes) to the possibility of record-setting storms.
Pre-season forecasts from the National Oceanic and Atmospheric Administration, the Colorado State University Tropical Meteorology Project and private firm Weather 2000, all make note that the United States is in the midst of an active hurricane cycle that is likely to continue for several seasons, despite the relative calm of the past three years.
This effect is particulary worrisome to officials because, as with any hurricane season, preparation is essential to minimizing harm.
“Planning and preparation is the key to storm survival and recovery,” said retired Navy Vice Adm. Conrad C. Lautenbacher, Ph.D., undersecretary of commerce for oceans and atmosphere and NOAA administrator.
“Americans in hurricane-prone states must get serious and be prepared . . . Everyone is part of the emergency management process,” said R. David Paulison, administrator, Federal Emergency Management Administration (FEMA). “We must continue to develop a culture of preparedness in America in which every American takes personal responsibility for his or her own emergency preparedness.”
NOAA PREDICTS NEAR-NORMAL OR ABOVE-NORMAL SEASON
The National Oceanic and Atmospheric Administration’s (NOAA) Climate Prediction Center in May stated that projected climate conditions point to a near-normal or above- normal hurricane season in the Atlantic Basin this year and urges residents in vulnerable areas to be fully prepared for the hurricane season.
The Climate Prediction Center outlook calls for considerable activity with a 65 percent probability of an above-normal season and a 25 percent probability of a near-normal season. This means there is a 90 percent chance of a near or above-normal season.
The climate patterns expected during this year’s hurricane season have in past seasons produced a wide range of activity and have been associated with both near-normal and above-normal seasons, NOAA stated. For 2008, the outlook indicates a 60 to 70 percent chance of 12 to 16 named storms, including six to nine hurricanes and two to five major hurricanes (Category 3, 4 or 5 on the Saffir-Simpson Scale).
An average season has 11 named storms, including six hurricanes for which two reach major status.
“The outlook is a general guide to the overall seasonal hurricane activity,” said Lautenbacher. “It does not predict whether, where or when any of these storms may hit land. That is the job of the National Hurricane Center (NHC) after a storm forms.”
Bill Read, director of NOAA’s National Hurricane Center, said, “Our forecasters are ready to track any tropical cyclone, from a depression to a hurricane, which forms in the Atlantic Basin. We urge coastal residents to have a hurricane plan in place before the season begins and NHC will continue to provide the best possible forecast to the public.”
The science behind NOAA’s outlook is rooted in the analysis and prediction of current and future global climate patterns as compared to previous seasons with similar conditions.
“The main factors influencing this year’s seasonal outlook are the continuing multi-decadal signal (the combination of ocean and atmospheric conditions that have spawned increased hurricane activity since 1995), and the anticipated lingering effects of La Niña,” said Gerry Bell, Ph.D., lead seasonal hurricane forecaster at NOAA’s Climate Prediction Center. “One of the expected oceanic conditions is a continuation since 1995 of warmer-than-normal temperatures in the eastern tropical Atlantic.”
NOAA’s Atlantic hurricane season outlook will be updated on August 7, just prior to what is historically the peak period for hurricane activity.
CSU FORECAST INCREASES RISK
In the 25th year in which the Colorado State University (CSU) Tropical Meteorology Project has made forecasts of the upcoming season’s Atlantic basin hurricane activity, the forecast team stated in early April that it expects the 2008 season to be “much more active than the average 1950-2000 season” based on information obtained through March 2008. (The CSU team was expected to update its forecast on June 3, after Hurricane Protection’s publication deadline for this issue.)
“We estimate that 2008 will have about 8 hurricanes (average is 5.9), 15 named storms (average is 9.6), 80 named storm days (average is 49.1), 40 hurricane days (average is 24.5), 4 intense (Category 3-4-5) hurricanes (average is 2.3) and 9 intense hurricane days (average is 5.0),” stated Philip J. Klotzbach, the chief author of the project’s report.
The probability of U.S. major hurricane landfall is estimated to be about 135 percent of the long-period average, according to the CSU team.
In all cases, the April 2008 forecast shows an increase from the team’s first 2008 forecast issued in December 2007 (see HP, Winter 2008, page 20).
The latest forecast is based on a new extended-range early April statistical prediction scheme that utilizes 58 years of past data. The influences of El Niño conditions are implicit in these predictor fields.
The current La Niña conditions were expected to continue to weaken at the start of the 2008 Atlantic hurricane season.
A significant focus of the CSU team’s recent research involves efforts to develop forecasts of the probability of hurricane landfall along the U.S. coastline. Whereas individual hurricane landfall events cannot be accurately forecast months in advance, the total seasonal probability of landfall can be forecast with statistical skill, the report stated.
“These evolving forecast techniques are based on a variety of climate-related global and regional predictors previously shown to be related to the forthcoming seasonal Atlantic Basin tropical cyclone activity and landfall probability,” the report stated.
10 Hurricane Lessons, Comments for the 2008 Atlantic Season
Weather 2000, New York, NY, is a meteorological consulting firm specializing in medium- and long-range weather analysis, prediction and climate research. Since 1997 it has worked with energy and commodity trading and insurance industries providing forecasts, research, summaries and consultations. It is a pioneer in the area of weather risk management.
Looking to the 2008 hurricane season, Weather 2000 reminds us that the percentage of tropical storms that evolve into hurricanes and the number of hurricanes that actually make U.S. landfall any given year are very much at the whim of local environmental conditions and synoptic steering patterns that can be accurately assessed only as the season is underway.
Still, from its research and past historical data, Weather 2000 offers these 10 important facts as this year’s season gets underway:
1. Although the record-setting 2005 Atlantic hurricane season set a benchmark after which all ensuing seasons would seem anti-climatic, 11 of the past 13 seasons have produced more storms than the long-term average (with only 1997 being decidedly below), and this trend is likely to continue during this active cycle of which we are in the midst.
2. In 2005, Hurricane Emily was the strongest Atlantic hurricane ever prior to August (160 mph), with Dennis being the second strongest ever prior to August (150 mph). This cautions that intense tropical storms can be a legitimate threat in the early stages of the summer.
3. It was quite remarkable that 2006 was able to produce even an average number of 10 tropical storms in light of two powerful inhibitory factors that evolved. Firstly, a weak El Niño event emerged much more rapidly during that summer than had been anticipated, essentially shutting down the back half of the season. Secondly, the perennial Saharan Air Layer was substantially more robust and persistent than usual, essentially choking numerous potential tropical waves before they could organize from August to October.
4. Those looking only at the U.S. might not realize what a dangerous bullet was dodged in 2007: For the first time in recorded history, two Category 5 hurricanes made landfall in North America in the same year (Dean in Mexico and Felix in Nicaragua). If either storm has moved just 50 miles farther north while in the eastern Atlantic, an alarming situation easily could have developed for U.S. cities.
5. Louisiana has lost 1,900 square miles of essential buffering wetlands and bayou forest from 1937 to 2000 due to coastal development and subsequent erosion. Similar losses of these natural buffers have taken place during the past century from Texas to Maine exponentially increasing the vulnerability of these regions to storm devastation.
6. That not a single hurricane made U.S. landfall the past three years as a Category 4 or Category 5 storm (Charlie [Cat. 4] in 2004 was the last, before that Andrew [Cat 5] in 1992) means things could have been worse the past three seasons.
7. Mostly due to geography, no hurricane since 1950 has ever directly struck from the upper Outer Banks of North Carolina to New York City (a mid-Atlantic coastal zone that represents scores of millions of people), but time eventually will run out on avoiding direct primary landfalls. Due to steering mechanisms and other projections, research concludes that there are higher odds that at least one hurricane will impact the U.S. Northeast/mid-Atlantic coast in 2008.
8. Research concludes that there remain decent odds that an Atlantic hurricane could achieve the strength of 191 to 200 mph sustained winds (never before officially observed in a tropical storm on planet Earth) during the 2008 season (Dean and Felix in 2007 came close with 175 mph sustained winds). The pressure intensity record of 882 mb (established by Wilma in 2005) also could be challenged in 2008.
9. Research has detected an evolution of the Inter-Tropical Convergence Zone (ITCZ) shifting farther southward toward the Equator. This now places traditional hurricane-proof islands such as Aruba, Bonaire and Curaço in tropical storms’ line-of-sight along with several Central American countries.
10. Much attention has been given to Sea Surface Temperature Anomalies (SSTA), which presently are warmer-than-normal across the sub-basins of the Gulf of Mexico, Sargasso Sea/Gulf Stream, and the Cape Verde/eastern Atlantic. But regardless of anomalies, tropical storms only require ocean temperatures above 75°F to form (even cooler for sub-tropical formation), and such temperatures are plentiful throughout the entire Atlantic basin.
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