Nav: Home

Evaluating forecasting models for predicting rainfall from tropical cyclones

October 17, 2016

Many people know that tropical cyclones and hurricanes cause high winds and storm surges. But two of their other effects, heavy rainfall and inland flooding, can be just as dangerous and impact larger areas.

Most recently, inland rainfall produced by Hurricane Matthew has caused record flooding in North Carolina, with the levels of some already swollen rivers and streams continuing to rise.

According to the National Oceanic and Atmospheric Administration (NOAA), more than 50 percent of the deaths associated with hurricanes from 1970 to 2004 were caused by fresh water flooding. And from 1981 to 2011, hurricane damage accounted for almost half--$417.9 billion--of the total monetary damage from all weather and climate disasters during that same time period (adjusted for inflation to 2011 dollars).

With the goal of providing basic information to help improve preparedness and mitigation efforts, new University of Iowa-led research published online in September in the Journal of Hydrology examined how accurate current forecasting systems are in predicting rainfall from North Atlantic tropical cyclones that reach land in the United States.

Comparing five state-of-the-art weather prediction models, researchers found current models can forecast both where and how much rainfall a tropical cyclone will produce up to two days in advance. However, the forecast's accuracy decreased significantly when the prediction window increased to five days. The researchers' findings were based on 15 North Atlantic hurricanes that came within at least 500 kilometers of the U.S. coastline from 2007 to 2012.

Gabriele Villarini, UI associate professor of civil and environmental engineering and corresponding author on the paper, says researchers honed in on predicting the impacts of tropical cyclones because that information is generally more useful than typical forecasts that predict how many storms are expected in a season.

"The more specific the information we can provide is, the more useful it will be. This is why we have been moving toward predicting U.S. landfalling tropical cyclone activity and the associated rainfall," he says.

Villarini, also an associate research engineer at the UI's renowned Iowa Flood Center, says while a 48-hour lead time is a good starting point in terms of warning, he will continue to conduct more research to improve these predictions.

"By improving our understanding of the processes that drive tropical cyclones and hurricanes, we will be better positioned to improve our ability to forecast these events and their impacts with longer and longer lead times," he says.

Gabriel Vecchi, head of the climate variations and predictability group at NOAA's Geophysical Fluid Dynamics Lab and another author on the paper, says decades of weather prediction data show that forecasts have improved--and will improve--as scientists learn more about hurricanes.

"We can't do anything about the past," he says. "The goal of this work is to provide better information in the future."

Vecchi, who has collaborated with Villarini on several research projects, says he values the expertise in flooding and hydrology that Villarini and the Iowa Flood Center bring to their partnership.

"This is one of these examples of interdisciplinary work that has been incredibly fruitful," he says.

The paper also was authored by Beda Luitel while he was a graduate student at the UI.
-end-
The Iowa Flood Center, IIHR­-Hydroscience and Engineering, the National Science Foundation, and the U.S. Army Corps of Engineers Institute for Water Resources funded the work.

University of Iowa

Related Rainfall Articles:

NASA looks at rainfall from Tropical Storm Dora
Now a tropical storm, Hurricane Dora has been skirting southwestern Mexico's coast since it formed and has transported tropical moisture onshore that has produced some heavy rain showers.
NASA adds up Tropical Storm Cindy's rainfall
Tropical storm Cindy was downgraded to a tropical depression after moving onshore near the Texas and Louisiana Border on Thursday June 22, 2017 and bringing a lot of rain with it.
Bangladesh's heavy rainfall examined with NASA's IMERG
At least 156 people in Bangladesh were killed during the past week by landslides and floods caused by heavy rainfall.
NASA looks at extreme Florida rainfall by satellite
Extremely heavy rain has recently fallen over Florida and the Global Precipitation Measurement or GPM mission core satellite looked at that some of that rainfall on June 7.
Summer rainfall in vulnerable African region can be predicted
Summer rainfall in one of the world's most drought-prone regions can now be predicted months or years in advance, climate scientists at the Met Office and the University of Exeter say.
NASA adds up record Australia rainfall
Over the week of May 15, extreme rainfall drenched northeastern Australia and NASA data provided a look at the record totals.
Varied increases in extreme rainfall with global warming
A new study by researchers from MIT and the Swiss Federal Institute of Technology in Zurich shows that the most extreme rain events in most regions of the world will increase in intensity by 3 to 15 percent, depending on region, for every degree Celsius that the planet warms.
NASA examines Peru's deadly rainfall
The Global Precipitation Measurement mission or GPM constellation of satellites provide data on precipitation rates and totals.
NASA examines Ex-Tropical Cyclone Dineo's rainfall
NASA examined the heavy rainfall generated by Tropical Cyclone Dineo as it made landfall in Mozambique and NASA's Terra satellite spotted the storm's remnants over four countries.
NASA observes extreme rainfall over Southern California
NASA calculated California's rainfall over seven days using a constellation of satellites and created a map to provide the visual extent of the large rainfall totals.

Related Rainfall Reading:

Best Science Podcasts 2019

We have hand picked the best science podcasts for 2019. Sit back and enjoy new science podcasts updated daily from your favorite science news services and scientists.
Now Playing: TED Radio Hour

Digital Manipulation
Technology has reshaped our lives in amazing ways. But at what cost? This hour, TED speakers reveal how what we see, read, believe — even how we vote — can be manipulated by the technology we use. Guests include journalist Carole Cadwalladr, consumer advocate Finn Myrstad, writer and marketing professor Scott Galloway, behavioral designer Nir Eyal, and computer graphics researcher Doug Roble.
Now Playing: Science for the People

#530 Why Aren't We Dead Yet?
We only notice our immune systems when they aren't working properly, or when they're under attack. How does our immune system understand what bits of us are us, and what bits are invading germs and viruses? How different are human immune systems from the immune systems of other creatures? And is the immune system so often the target of sketchy medical advice? Those questions and more, this week in our conversation with author Idan Ben-Barak about his book "Why Aren't We Dead Yet?: The Survivor’s Guide to the Immune System".