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”).