NOAA NATIONAL WEATHER SERVICE FORECAST FOR KATRINA
WAS RIGHT ON THE MARK
By Chris Vaccaro

November 15, 2005 — Hurricane Katrina, with winds screaming to an estimated 140 mph and a raging surge of water towering to heights of a three-story building, decimated a vast area of Louisiana, Mississippi and Alabama and established itself as one of the most lethal and destructive storms to strike the United States.

Katrina’s fury began innocently enough from a cluster of thunderstorms brewing over the Bahamas, which organized into a tropical depression — the first life stage of a tropical cyclone — on August 23.

From mid-August through mid-October the Atlantic Basin is considered to be in its climatological peak as favorable winds patterns and the abundance of ocean water above 80 degrees Fahrenheit help spawn tropical storms and hurricanes in greater numbers and to greater strength. Such ideal conditions contributed to Katrina’s rise.

Winds with the depression soon increased to 40 mph and the tropical cyclone was upgraded to this season’s 11th tropical storm and given the name Katrina on August 24 — 13 years after Hurricane Andrew devastated South Florida with 165 mph winds.

Katrina reached hurricane strength before moving ashore in southeast Florida, near North Miami Beach, with 80 mph sustained winds on August 25. Wind gusts at the NOAA National Hurricane Center that evening climbed to 87 mph before settling to near calm as Katrina’s eye passed directly over the very forecasters wary of the storm’s impending track toward the warm and energizing water of the Gulf of Mexico.

Katrina rapidly intensified over the open Gulf of Mexico, reaching its peak with top sustained winds of 175 mph — a catastrophic Category 5 on the five-level Saffir-Simpson Hurricane Scale, which ranks hurricanes based on their damage potential. Katrina’s central pressure, inversely correlated to wind speed, plummeted to 902 millibars — the sixth lowest recorded in the entire Atlantic Basin.

With the Gulf of Mexico nearly landlocked, hurricanes inside the basin are bound to hit a coastline. And with steering currents tugging Katrina northward it would be the southern United States, and not Mexico with cause for alarm.

Amid the increasingly dire hurricane track, forecasters with the NOAA National Weather Service were steadfast in providing critical weather forecasts, while accommodating an influx of media and public inquiries and conducting essential forecast briefings with federal, state and local emergency officials.

In bracing for the storm’s wrath, NOAA facilities in the central Gulf Coast region were evacuated or activated continuity plans to minimize service interruptions as Katrina hit. The National Weather Service office in Slidell, La., became a refuge for most staff members and their families.

Farther south inside the nerve center of the NOAA National Hurricane Center in Miami, Director Max Mayfield led the extensive outreach to the public and the emergency management community with support from the center’s hurricane experts and special team of meteorologists assembled from across NOAA. Mayfield also took the initiative to call the governors of Louisiana and Mississippi and the New Orleans mayor to ensure their awareness of the situation. Once more, NOAA’s National Hurricane Center was America's calm, clear and trusted voice when it matters most.

“NOAA employees continue to demonstrate their tenacity to rise above adversity,” said Brig. Gen. David L. Johnson, U.S. Air Force (Ret.), director of the NOAA National Weather Service. “Proactive and collaborative efforts enhance the safety of NOAA team members and assures the delivery of critical weather and water services along the Gulf Coast.”

As if foreshadowing the news stories that followed Katrina, the Slidell Weather Forecast Office issued a firm statement to people in the hurricane’s path that included the following messages:

“Most of the area will be uninhabitable for weeks…at least one half of well constructed homes will have roof and wall failure... Airborne debris will be widespread and may include heavy items such as household appliances and even light vehicles… Persons, pets and livestock exposed to the wind will face certain death if struck. Power outages will last for weeks as most power poles will be down and transformers destroyed. Water shortages will make human suffering incredible by modern standards.”

In the final hours before landfall, Katrina’s winds slowly decreased.

Katrina slammed into southeast Louisiana on the morning of August 29 as an estimated powerful Category 4 hurricane with winds of 140 mph. Landfall was consistently projected to occur in this area by the NOAA National Hurricane Center more than two days in advance and where a hurricane warning was issued more than 30 hours prior — warnings are typically issued within 24 hours prior to the onset of hurricane conditions.

Advances in hurricane research and computer forecast modeling coupled with continuous data from NOAA and U.S. Air Force hurricane hunter aircraft on the atmospheric conditions inside and surrounding Katrina aided National Hurricane Center forecasters in producing such accurate track and intensity forecasts with extended lead times.

“The most accurate forecasts are only beneficial when people react by taking the necessary steps to save their lives and property,” said Mayfield. “Preparedness remains essential. Knowing the risks, knowing ahead of time where to go and what to bring if evacuating, and heeding orders from local officials empowers individuals, businesses and communities.”

As Katrina steadily dissipated while spinning northward across the Tennessee Valley, NOAA offices including the National Weather Service Forecast Office and the Lower Mississippi River Forecast Center in Slidell, La., and the National Data Buoy Center in Stennis Space Center, Miss., reacted quickly to the storm’s debilitating blows of structural damage and communication loss. Fortunately all NOAA team members remained safe.

Teams of people and equipment were dispatched to the disaster area to maintain weather services, support rescue and recovery operations, and ensure the safety of personnel.

Several Weather Forecast Offices provided backup assistance to neighboring offices lacking adequate communications. The forecast office in Mobile, Ala., for example, issued forecasts and warnings on behalf of the Slidell office, which worked diligently with National Weather Service Southern Region Headquarters to regain communications and use of Doppler weather radar.

In support of emergency operations, Weather Forecast Offices offered assistance to emergency response teams as Incident Meteorologists and Remote Area Weather Systems were deployed to the disaster area to provide on-site weather services.

Katrina not only impacted the area where people work, but also where they live. While team NOAA rose to the occasion professionally, they personally faced homes rendered destroyed or uninhabitable, and once familiar communities were now unrecognizable.

As with most deadly and destructive storms, it’s inevitable that Katrina will join Hugo, Andrew, Charley, Ivan and many others on the list of retired storm names. A replacement will be selected by the World Meteorological Organization to replace Katrina’s spot on the list of storm names, recycled every six years, for the year 2011.

Relevant Web Sites
Hurricane Katrina

NOAA National Hurricane Center

NOAA National Weather Service

Media Contact:
Greg Romano, NOAA Weather Service, (301) 713-0622 ext. 169 or Chris Vaccaro, NOAA Weather Service, (301)713-0622 x134