It sat silently off the southwest coast of Florida last Friday -
a vast pool of unusually warm seawater as well suited to a salt-
water spa as to the open subtropical ocean. Meanwhile, high above, a
filament of high-speed air had peeled away from its mother flow, the
For hurricane Charley, heading north after clearing Cuba, meeting
this patch of ocean was like turbocharging a locomotive. Fueled by
the unusually warm water below and the right wind environment aloft,
Charley stunned forecasters as it grew from a worrisome storm to a
major hurricane shortly before landfall, packing sustained winds of
more than 145 miles an hour.
"It was like a runaway train," says Peter Black, a scientist at
the Atlantic Oceanographic and Meteorological Laboratory in Miami,
part of the National Oceanic and Atmospheric Administration (NOAA).
"It was our worst nightmare."
Charley's sudden growth spurt represents one of the most
challenging aspects of hurricane forecasting. Yet atmospheric
scientists say they are hopeful that over the next few years, they
will be able to provide forecasters with the tools to significantly
improve forecasts of hurricane intensity. New forecast models are
being assembled and tested. New sensors, satellites, and field
studies are being planned. And recent field and lab studies are
yielding fresh insights into the conditions that give tropical
cyclones more kick.
It's a long, grinding process that moves only as fast as budgets
and storm frequency allow. Still, "within the next five years it
will be possible to do 20 to 25 percent better than we're doing now"
just by making better use of available reconnaissance data gathered
from storms, says Mark DeMaria, a NOAA researcher who developed the
rudimentary tools for forecasting intensity that the National
Hurricane Center now uses. Over the next decade, the highly
sophisticated computer models under development should boost
improvements further, he says.
What makes the intensity problem so fiendishly difficult to
solve? "It's far more complex" than track forecasting, acknowledges
Naomi Surgi, who heads the hurricane forecasting modernization
effort at the National Centers for Environmental Prediction (NCEP)
in Camp Springs, Md. Scientists must identify and understand how
large-scale factors, such as regional atmospheric circulation
patterns, affect tropical cyclones. They also have to focus on
processes within hurricanes that can occur on scales as small as a
few tens of meters across. It's all about heat moving from the ocean
into and through the storm and the factors that can affect the
Take the boundary between air and ocean, for example. Existing
forecast models assume that when a hurricane grows stronger and its
wind speeds increase, the wind kicks up ever-larger waves. As the
waves grow, friction increases between wind and wave, slowing the
pace at which a storm strengthens.
Studies published over the past year, however, suggest that this
assumption is wrong. The ocean's drag on the wind grows until the
winds hit hurricane force, says Isaac Ginis, a professor of
oceanography at the University of Rhode Island's Graduate School of
Oceanography in Narragansett, R. …