BOULDER — Two DOW (Doppler on Wheels) mobile radars have arrived near Mobile, Alabama, and are being readied to intercept the eye of Hurricane Ivan as it hits land. The radars will collect unprecedented high-resolution Doppler radar data and wind measurements from inside the storm. Josh Wurman, director of the DOW program of the Center for Severe Weather Research (CSWR), is on site near Mobile and available by cell phone to speak with reporters, as conditions allow.

By scanning inside a hurricane's eye, the DOWs can see intense storm features as small as 40 feet across, resolving very small-scale but potentially damaging wind streaks, gusts, and other structures.

The DOWs are operated by the CWSR, based in Boulder, and were developed in partnership with the National Center for Atmospheric Research (NCAR). The radars are primarily supported by the National Science Foundation (NSF).

The two advanced mobile Doppler radars are mounted on hardened truck beds constructed to withstand the rigors of the hurricane environment, including winds over 130 miles per hour and airborne debris. They have intercepted the eyes of seven hurricanes: Fran, Bonnie, Floyd, Georges, Lili, Isabel and, and, most recently, Frances. Frances was the first hurricane in which the DOWs were able to observe direct onshore wind flow over the water from ranges as low as 100 meters (about 330 feet).

Last year, in the throes of Hurricane Isabel, the DOWs collected the highest-ever resolution in multiple-Doppler data from a hurricane. The data resulted in the discovery of an entirely new phenomenon in hurricanes, called intense boundary layer rolls, which contain the highest and most dangerous wind gusts, with the potential to cause the most damage.

The DOW radars have revolutionized the study of tornadoes and other violent and small-scale atmospheric phenomena, according to CSWR director Josh Wurman. DOWs have measured the highest wind speeds ever recorded near Earth's surface: 301 mph in a tornado. They have been deployed in wide-ranging research environments, including wild fires, homeland security experiments, aviation-related turbulence, winter weather, birth of storms, mountain weather in the Alps, and 20 other projects in recent years.

DOW Images:

http://www.cswr.org/2003-0914/dow2-cropped.jpg A DOW in action

http://www.cswr.org/2003-0914/Barrel%20updraft%20and%20DOW.jpg A DOW near a storm

http://www.cswr.org/2003-0914/Fire_plume_aug_1st_no1.JPG a DOW near a fire

http://www.cswr.org/2003-0914/dow.smallB&W.jpg The new Rapid-DOW w/small tornado

http://www.cswr.org/2003-0914/georges.1009.d3.gif Inside the radar eye of Hurricane Georges

http://www.cswr.org/2003-0914/georges.0846.d3.gif Windstreaks / gusts inside Georges

http://www.cswr.org/docs/truck2final-j1.jpg A DOW with a tornado

On the Web:

For high-resolution hurricane track forecasts from the multiagency Weather Research and Forecasting (WRF) model, see http://rain.mmm.ucar.edu/wrf

The forecasts can be viewed by choosing "120h Hurr WRF" (a lower-resolution, five-day forecast) or "4km WRF"(a higher-resolution, 48-hour forecast) under "Model Selection." Plotting options include surface pressure ("SFC"), surface wind speed ("sfc wind"), and rainfall ("sfc precip").