Researchers get insight into how storms become raging canes

[HurricaneJoe22]

Interesting story here from the Sun-Sentinel...good to see they're making some headway in this area



Researchers get some insight into how storms become raging hurricanes

By Ken Kaye
sun-sentinel.com
Posted March 1 2007, 2:50 PM EST

It remains a meteorological mystery: Why do some hurricanes suddenly spin into raging tempests while others quickly deflate into meek tropical storms?

Researchers now have better insight into that phenomenon: The rain bands outside a hurricane's eye come together to form a new eye wall -- or simply put, the storm reinvents itself.

This was the finding of a study conducted by a conglomerate of federal agencies and universities, focusing on the chaotic 2005 season, to be released Friday in the journal Science.

It should help forecasters at the National Hurricane Center in Miami improve their storm-strength predictions, an area where they have struggled, said Shuyi Chen, of the University of Miami Rosentiel School of Marine and Atmospheric Science, who played a leading role in the study.

"We can see very clearly now what's going on with the hurricane eye," she said.

Called the Hurricane Rainband and Intensity Change Experiment, or RAINEX, the study found that as a storm swirls into a tighter spin, a moat of dry air develops around a hurricane eye, where the strongest winds are found.

Ultimately, the dry air destroys the original eye. Meanwhile, rain bands around the core form a new eye but temporarily weaken the storm in the process. The system then can re-intensify to even greater strength, said Chen, an associate professor of meteorology and oceanography.

"Think of an ice skater with her spread arms out and then brings her arms in to spin faster," she said. "This interaction is very complex and at the very core of why a hurricane can change very quickly from a Category 3 to a Category 5."

The National Oceanic and Atmospheric Administration, the hurricane center's parent agency, has invested millions of dollars in studies and technological tools to unlock the reasons into why storms suddenly intensify.

Among other things, it has learned that hurricanes can quickly bulk up after passing over extremely warm stretches of water, such as the loop current in the Gulf of Mexico.

NOAA provided two P-3 turboprops and the U.S. Navy provided a third to help research RAINEX during the 2005 storm season. The University of Washington and the National Center for Atmospheric Research in Boulder, Colo., also participated in the study, which was funded by the National Science Foundation.

Critical to the study was employing a high-resolution radar on the Navy P-3 to observe the eye wall of Hurricane Rita undergo a replacement, said Robert Houze Jr., a professor of atmospheric sciences at the University of Washington and lead author of the study.

The plane was able to do so by flying circles between the two eye walls, something that had never been done before, he said. That provided an enormous amount of detail that will allow hurricane forecast models to be more accurate in the future, he said.

Curiously, he added, Hurricane Katrina did not undergo an eye wall replacement, even though it followed a path through the Gulf of Mexico very similar to Rita's.

"One of the on-going challenges we have to do next is to understand the subtle differences between those two storms," he said.

[LSU2001]

Good Post Joe,
Interesting read.
I think this was the project that Derek was a part of. He has mentioned RAINEX several times in his posts.

Curiously, he added, Hurricane Katrina did not undergo an eye wall replacement, even though it followed a path through the Gulf of Mexico very similar to Rita's.

"One of the on-going challenges we have to do next is to understand the subtle differences between those two storms," he said.[b]

I wonder if the above quote may have something to do with the annular characteristics that Katrina displayed as opposed to Rita. I don't know but it is interesting to think about.
Thanks,
TIm

[Derek Ortt]

Katrina was nowhere near annular. It had a large spiraling rainband pattern as depicted by TMI imagery. It is that spiraling pattern that may have prevented an EWRC (Rita had a circular rainband pattern, much mroe favorable for an EWRC)

[pojo]

Why does everything and everybody claim the NOAA P3 Aircraft as THE Hurricane Hunters.... wake up people.

[brunota2003]

Why does everything and everybody claim the NOAA P3 Aircraft as THE Hurricane Hunters.... wake up people.

Because most people who write news articles arent weather savy?