Rita and Beyond: Research Model Advances Hurricane Intensity Prediction

With its high-resolution grid of data points just four kilometers(about 2.5 miles) apart, the model can project the location offine-scale rain bands and eyewall structures 48 hours into the future.

It's these storm features that determine where the greatestdamage from both rain and wind might occur, says NCAR weather expertChris Davis. Current operational forecast models use a coarserresolution and must approximate the cloud processes affecting intensityand precipitation.

Known as ARW, the computer model is NCAR's research version ofthe Weather Research and Forecasting model (WRF), a joint effort byuniversity and government scientists.

"ARW intensity predictions are very encouraging," says Davis."Five years ago, accurate intensity predictions weren't even possible."

The model captured in detail the collapse of HurricaneKatrina's eyewall at landfall and the shift of precipitation to thenorth side of the storm. Had the eyewall's structure remained coherent,the winds would have been far more devastating. However, an eyewallalways weakens at landfall, says Davis.

Teams supporting the Department of Energy and Department ofHomeland Security are using real-time ARW data in their damage models.The researchers are testing how computer simulations of a particularhurricane's most destructive features might improve damage modelprojections and lead to better warnings of floods, power outages, androad blockage. This year's test cases have included hurricanes Katrina,Ophelia, and now Rita.

Meanwhile, a hurricane experiment in Florida is investigatingthe interactions between Hurricane Rita's rain bands and its eyewall.NCAR's Wen-Chau Lee is flying through the storm aboard a Naval ResearchLaboratory P-3 aircraft to gather radar data from inside the bands. Theobservations from the Hurricane Rainband and Intensity ChangeExperiment (RAINEX) will help scientists better understand the impactof the rain bands on the storm's maximum winds.